Co-reporter:Liang Wang;Shaojun Guo;Erkang Wang
The Journal of Physical Chemistry C September 4, 2008 Volume 112(Issue 35) pp:13510-13515
Publication Date(Web):2017-2-22
DOI:10.1021/jp804347q
In this paper, we have explored a simple and new strategy to obtain quasimonodisperse Au/Pt hybrid nanoparticles (NPs) with urchinlike morphology and controlled size and Pt shell thickness. Through changing the molar ratios of Au to Pt, the Pt shell thickness of urchinlike Au/Pt hybrid NPs could be easily controlled; through changing the size of Au NPs (the size was easily controlled from ∼3 to ∼70 nm via simple heating of HAuCl4-citrate aqueous solution), the size of urchinlike Au/Pt hybrid NPs could be facilely dominated. It should be noted that heating the solution (100 °C) was very necessary for obtaining three-dimensional (3D) urchinlike nanostructures while H2PtCl6 was added to gold NPs aqueous solution in the presence of reductant (ascorbic acid). The electrocatalytic oxygen reduction reaction (ORR, a reaction greatly pursued by scientists in view of its important application in fuel cells) and the electron-transfer reaction between hexacyanoferrate(III) ions and thiosulfate ions of urchinlike Au/Pt hybrid NPs were investigated. It is found that the as-prepared urchinlike Au/Pt hybrid NPs exhibited higher catalytic activities than that of ∼Pt NPs with similar size.
Co-reporter:Lingling Zhang, Lu Bai, Miao Xu, Lei Han, Shaojun Dong
Nano Energy 2015 Volume 11() pp:48-55
Publication Date(Web):January 2015
DOI:10.1016/j.nanoen.2014.10.020
•Dual route energy conversion, including light energy to electricity and chemical energy to electricity.•Both the visible-light driven anode and cathode.•High performance with an open circuit voltage of 1.13 V and the maximum power density of 0.27 mW cm−2.•Simple configuration with a single portable light source.•Fast response to the visible light and stable power output.A membrane-less ethanol/air biofuel cell (BFC) with both the anode and cathode driven by visible light has been assembled. Simply upon a light source illumination, the BFC generates the maximum power density of 0.27 mW cm−2 with an open circuit voltage of 1.13 V, realizing the dual route energy conversion of light energy and chemical energy to electricity, improving the energy utilization efficiency.
Co-reporter:Ling Liu, Junfeng Zhai, Chengzhou Zhu, Ying Gao, Yue Wang, Yanchao Han, Shaojun Dong
Biosensors and Bioelectronics 2015 Volume 63() pp:483-489
Publication Date(Web):15 January 2015
DOI:10.1016/j.bios.2014.07.074
•One-pot hydrothermal method to prepare three-dimensional rGO based gel (GelrGONR).•Neutral red is employed to mediate the assembly of rGO sheets and tune the pore sizes of GelrGONR.•3-dimentional spatial immobilization of microbe on the GelrGONR was obtained (GelrGONR-M).•BE of immobilized microbe on GelrGONR is higher than that on commonly supports.•The GelrGONR-M as a biocatalyst was used for establishing biochemical oxygen demand biosensor.We report a hydrothermal method to prepare reduced graphene oxide (rGO)-based hydrogel (GelrGONR), using neutral red (NR) to mediate the assembly of rGO sheets and tune the pore size of GelrGONR. A series of techniques including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy and BET were employed to characterize the physico-chemical properties of GelrGONR. A large pore size of up to 20 µm and interconnected porous structure of GelrGONR were obtained. GelrGONR was used as a support for immobilizing microbe (denoted as GelrGONR-M), which showed ~3.3 times more load mass of microbe than commonly used supports (i.e., activated carbon and carbon fiber felt) and 2.5 times higher biodegradation efficiency (BE) than carbon fiber felt. Further use of GelrGONR-M as a biocatalyst for establishing a BOD biosensor exhibits a linear range of 2–64 mg O L−1 and a detection limit 0.4 mg O L−1 for glucose–glutamic acid (GGA). Moreover, our proposed BOD detection strategy shows a long-term viability over one year and stability up to 2 months with a relative standard deviation of 2.1%. Our results demonstrated the great potential of employing GelrGONR as a microbe-immobilization support for biosensor development.
Co-reporter:Chengzhou Zhu, Junfeng Zhai and Shaojun Dong
Nanoscale 2014 vol. 6(Issue 17) pp:10077-10083
Publication Date(Web):19 Jun 2014
DOI:10.1039/C4NR02400A
Ionic liquid (IL)-induced three-dimensional macroassembly of graphene (GN) has been achieved through one-step hydrothermal treatment. Significantly, the three-dimensional GN–IL (TGN–IL) nanostructures provide ideal electrode materials for supercapacitors because they combine the unique properties of GN and IL in overcoming the restacking of GN, enlarging the specific surface area, improving the GN conductivity and ensuring the high electrochemical utilization of GN as well as the open channels provided by 3D nanostructures.
Co-reporter:Yanling Zhai, Chengzhou Zhu, Erkang Wang and Shaojun Dong
Nanoscale 2014 vol. 6(Issue 5) pp:2964-2970
Publication Date(Web):20 Dec 2013
DOI:10.1039/C3NR05357A
Novel Co–N–C hybrids were successfully fabricated via one-step pyrolysed soy milk with the aid of cobalt(II) nitrate in a synthetic process. Because of the formation of the Co–N–C structures, the resulting product showed excellent electrocatalytic activity for the ORR in alkaline electrolytes, potentially making Co–N–C a nonprecious metal cathode catalyst for ORR. The technique can also be scaled up easily and this research provides a great opportunity for industry to produce an eco-friendly carbon nanomaterial for fuel cells and other electrochemical energy devices.
Co-reporter:Zhikun Xu, Lei Han, Baohua Lou, Xiaowei Zhang and Shaojun Dong
Journal of Materials Chemistry A 2014 vol. 2(Issue 14) pp:2470-2474
Publication Date(Web):10 Jan 2014
DOI:10.1039/C3TC32400A
A series of photodetectors based on BiOBrxI(Cl)1−x films are fabricated via a facile and rapid interfacial self-assembly method. The photodetectors show a high signal to noise ratio, and the cutoff wavelength can be tuned over a broad range from the visible to the ultraviolet region simply by changing the composition of the BiOBrxI(Cl)1−x films.
Co-reporter:Lei Han, Lu Bai and Shaojun Dong
Chemical Communications 2014 vol. 50(Issue 7) pp:802-804
Publication Date(Web):24 Oct 2013
DOI:10.1039/C3CC47080F
A novel self-powered ultraviolet (UV) photodetector was successfully constructed through combining Pt-modified TiO2 nanotubes and Prussian blue (PB)-modified ITO, in which the existence of UV could be judged easily by naked eye with the aid of PB for electrochromic display. More importantly, it could also self-recover without UV light illumination.
Co-reporter:Zhikun Xu, Lei Han, Peng Hu and Shaojun Dong
Catalysis Science & Technology 2014 vol. 4(Issue 10) pp:3615-3619
Publication Date(Web):29 Jul 2014
DOI:10.1039/C4CY00889H
Uniform and small Ag@AgCl nanoparticles were for the first time prepared through a vapor diffusion strategy at room temperature. The size of the Ag@AgCl nanoparticles could be controlled by a diffuse vapor of HCl molecules with a slow rate and PVP used as a precursor. The smallest Ag@AgCl NPs exhibit excellent photocatalytic activity and stability.
Co-reporter:Lei Han, Peng Hu, Zhikun Xu, Shaojun Dong
Electrochimica Acta 2014 Volume 115() pp:263-268
Publication Date(Web):1 January 2014
DOI:10.1016/j.electacta.2013.10.171
•A series of BiOIαCl1-α solid solution electrode were successfully prepared through a simple electrodeposition method.•All prepared BiOIαCl1-α electrodes exhibited p-type conductivity.•The BiOIαCl1-α solid solution showed the best photoelectrochemical activity at α = 0.5.In this paper, a series of BiOIαCl1-α solid solution electrodes were successfully prepared through a simple electrodeposition method. The obtained electrodes were characterized by X-ray diffraction, scanning electron microscopy, UV–vis diffuse reflectance spectroscopy and photocurrent response. We found that all prepared electrodes exhibited p-type conductivity in accordance with reports employing other deposition strategies. What's more, the BiOIαCl1-α solid solution showed the best photoelectrochemical activity at α = 0.5 due to the balance between the level of conduction band and the light absorption ability of solid solutions. Finally, wet photovoltaic cells with p-BiOI0.5Cl0.5 and n-TiO2 nanotube array electrodes were also constructed.In this paper, a series of BiOIαCl1-α solid solution electrodes were successfully prepared through a simple electrodeposition method. It is interestingly found that all prepared electrodes exhibited p-type conductivity, and the BiOIαCl1-α solid solution showed the best photoelectrochemical activity at α = 0.5 due to the balance between the level of conduction band and the light absorption ability of solid solutions.
Co-reporter:Liu Deng, Chaogui Chen, Chengzhou Zhu, Shaojun Dong, Hongmei Lu
Biosensors and Bioelectronics 2014 Volume 52() pp:324-329
Publication Date(Web):15 February 2014
DOI:10.1016/j.bios.2013.09.005
•GO@SiO2@CeO2 hybrid nanosheets with intrinsic peroxidase-like activity were successfully synthesized.•GSCs have great potential as an alternative to the commonly employed peroxidase.•An easy colorimetric bioactive paper was fabricated based on GSCs.•Glucose, lactate, uric acid and cholesterol can be well detected by the naked eyes.In this paper, Graphene oxide@SiO2@CeO2 hybrid nanosheets (GSCs) have been successfully synthesized by the wet-chemical strategy. TEM, FITR and XPS were applied to characterize the morphology and composition of the nanosheets. The colorimetric assay of these nanosheets indicated that they possessed high intrinsic peroxidase activity, which should be ascribed to the combination of graphene oxide and CeO2. A fully integrated reagentless bioactive paper based on GSCs was fabricated, which were able to simultaneously detect glucose, lactate, uric acid and cholesterol. The results demonstrated that GSCs have great potential as an alternative to the commonly employed peroxidase in daily nursing and general physical examination.
Co-reporter:Lu Bai, Lihua Jin, Lei Han and Shaojun Dong
Energy & Environmental Science 2013 vol. 6(Issue 10) pp:3015-3021
Publication Date(Web):19 Jul 2013
DOI:10.1039/C3EE41028E
An integrated self-powered fluorescence switch system based on biofuel cells (BFCs) is initially presented in this paper. With the aid of the electroactive material Prussian blue (PB) as the controller of fluorescence change and the biocatalysis, the fluorescence switch and electricity generation could be achieved in one BFC. Due to its excellent electrochromic property and suitable redox potential, PB not only acted as the electrochromic component to switch the fluorescence from Ru(bpy)32+-doped silica nanoparticles effectively, but also constructed membraneless and mediatorless BFCs through connecting with the bioelectrode. Furthermore, the self-powered fluorescence switch system possessed excellent reversibility and reproducibility, and delivered a power density up to 87 μW cm−2, demonstrating the potential of independent and sustainable electronics to harvest energy from the environment.
Co-reporter:Libing Zhang, Jinbo Zhu, Zhixue Zhou, Shaojun Guo, Jing Li, Shaojun Dong and Erkang Wang
Chemical Science 2013 vol. 4(Issue 10) pp:4004-4010
Publication Date(Web):10 Jul 2013
DOI:10.1039/C3SC51303C
Dynamic DNA assembly, operated in an autonomous and reconfigurable manner by controlling the kinetics of strand displacement reactions (SDR), is an ideal approach to amplify the fluorescent signals for molecular diagnostic and imaging. Herein, we for the first time have demonstrated an enhancement of fluorescence intensity of DNA/Ag nanocluster-based beacons by the modulation of SDR. This is a new DNA/Ag NCs fluorescence light-up system through the use of the enhancer of G-rich overhang. Such a sensing system can be used to develop a DNA/Ag nanocluster-based beacon for the fluorescent detection of nucleic acid and thrombin with high selectivity and sensitivity, in which the detection sensitivity could be further enhanced through additional Exo III based amplification.
Co-reporter:Shu Jiang, Chengzhou Zhu and Shaojun Dong
Journal of Materials Chemistry A 2013 vol. 1(Issue 11) pp:3593-3599
Publication Date(Web):18 Jan 2013
DOI:10.1039/C3TA01682J
We demonstrated a facile method to synthesize nanosheet-like cobalt–nitrogen–graphene (Co–N–GN) composites acting as a highly active non precious metal-based catalyst for oxygen reduction reaction (ORR). Polypyrrole/graphene oxide (PPy/GO) nanocomposites were first synthesized via in situ polymerization at room temperature. Then, cobalt(II) nitrate was directly incorporated into the PPy/GO hybrids via annealing heat treatment to generate Co–N–GN composites. The as-synthesized Co–N–GN composites exhibited an extraordinary electrocatalytic performance towards ORR comparable to commercial Pt/C, for instance, high onset potential, superior methanol tolerance, and excellent stability in alkaline medium, making them the state-of-the-art non-precious metal ORR electrocatalysts for electrochemical energy applications.
Co-reporter:Chengzhou Zhu and Shaojun Dong
Nanoscale 2013 vol. 5(Issue 22) pp:10765-10775
Publication Date(Web):06 Sep 2013
DOI:10.1039/C3NR03280A
Graphene (GN) is an emerging carbon material that may soon find practical applications. With its unusual properties, GN is an ideal platform for constructing a series of GN-based functional nanomaterials. Among them, GN/noble metal hybrids become one of the families of composite materials with extraordinary properties by combining the advantages of noble metal nanostructures and GN. The recent progress in the synthesis of GN/noble metal hybrids is presented first, such as in situ solution based methods, electrochemical deposition methods, self-assembly and other methods. Then, the applications of these novel GN/noble metal hybrids in fuel cells are summarized and discussed. Future research trends and challenges of design and synthesis of GN/noble metal hybrids are proposed.
Co-reporter:Yanling Zhai, Zhijun Zhu, Chengzhou Zhu, Jinbo Zhu, Jiangtao Ren, Erkang Wang and Shaojun Dong
Nanoscale 2013 vol. 5(Issue 10) pp:4344-4350
Publication Date(Web):13 Mar 2013
DOI:10.1039/C3NR00254C
Reversible three-state fluorescence switches triggered by light, electricity and chemical inputs based on “sponges” of Pyronin Y-doped silica nanoparticles (PYDS) and polyoxometalate K14[Na(H2O)P5W30O110] (Na-POMs) core–shell nanostructures were realized. Under one or two signal inputs, the system exhibited distinct three-state interconvertible automaton, achieving reversible “on” and “off” luminescence switches via the related luminescence quenching effect. The features of the system correspond to the equivalent circuitry of an IMPLICATION logic gate performing the Boolean operation by using potential and chemical as inputs. Such a multi-chromic device with novel structure possesses several advantages, such as relative low operation voltage, large reproducibility and reversibility, apparent fluorescence contrast, and long-time stability, which make it a suitable candidate for nonvolatile memory devices. In addition, the current protocol for the hybrid film fabrication can be easily extended from the polyoxometalate and organic dyes to other novel nanostructures matched multifunctional stimulus-responsive species and fluorescence materials in the future.
Co-reporter:Chengzhou Zhu and Shaojun Dong
Nanoscale 2013 vol. 5(Issue 5) pp:1753-1767
Publication Date(Web):03 Jan 2013
DOI:10.1039/C2NR33839D
Development of state-of-the-art electrocatalysts with inexpensive and commercially available materials to facilitate sluggish cathodic oxygen reduction reaction (ORR) is a key issue in the development of fuel cells and other electrochemical energy devices. Although great progress has been achieved in this area of research and development, there are still some challenges in both their ORR activity and stability. The emergence of graphene (GN) provides an excellent alternative to electrode materials and great efforts have been made to utilize GN-based nanomaterials as promising electrode materials for ORR due to the high electrical conductivity, large specific surface area, profuse interlayer structure and abounding functional groups involved. It should be noted that rational design of these GN-based nanomaterials with well-defined morphology also plays an important role in their electrochemical performance for ORR. Considerable attempts were achieved to construct a variety of heteroatom doped GN nanomaterials or GN-based nanocomposites, aiming at fully using their excellent properties in their application in ORR. In this critical review, in line with the material design and engineering, some recent advancements in the development of GN-based electrocatalysts for ORR in electrochemical energy devices (fuel cells and batteries) are then highlighted, including heteroatom-doped GN nanomaterials, GN-based nonprecious hybrid nanocomposites (GN/metal oxides, GN/N-M, GN/carbon nitride, etc.) and GN/noble metal nanocomposites.
Co-reporter:Lingling Zhang, Lei Han, Peng Hu, Li Wang and Shaojun Dong
Chemical Communications 2013 vol. 49(Issue 89) pp:10480-10482
Publication Date(Web):10 Sep 2013
DOI:10.1039/C3CC46163G
TiO2 nanotube arrays (NTA), prepared by potentiostatic anodization, were discovered to possess an intrinsic peroxidase-like activity. The colorimetric and electrochemical assays both demonstrated their excellent catalytic activity towards H2O2 reduction. On this basis, a simple and inexpensive electrochemical biosensor for glucose detection was developed.
Co-reporter:Lei Han, Zhikun Xu, Ping Wang and Shaojun Dong
Chemical Communications 2013 vol. 49(Issue 43) pp:4953-4955
Publication Date(Web):08 Apr 2013
DOI:10.1039/C3CC41798K
A novel and facile method is developed to prepare an Ag@AgCl film which exhibits high photocatalytic activity under visible light irradiation. In addition, it can also be used to fabricate a photodetector that possesses a fast response time and good photocurrent reproducibility.
Co-reporter:Zhixue Zhou, Yaqing Liu and Shaojun Dong
Chemical Communications 2013 vol. 49(Issue 30) pp:3107-3109
Publication Date(Web):27 Feb 2013
DOI:10.1039/C3CC39272D
We present a unique, label-free and resettable molecular keypad lock that utilizes DNA-modulated Ag nanoclusters (Ag NCs) as signal responsers. The present work demonstrates the first example that exonuclease-catalyzed DNA hydrolysis reaction could be used to achieve the RESET function of a molecular keypad without complicated procedures.
Co-reporter:Liu Deng, Ling Liu, Chengzhou Zhu, Dan Li and Shaojun Dong
Chemical Communications 2013 vol. 49(Issue 25) pp:2503-2505
Publication Date(Web):07 Feb 2013
DOI:10.1039/C3CC38776C
Hybrid AuNCs@SiO2@GQDs nanocomposites were synthesized via a multistep procedure; GQDs located near AuNCs showed enhanced fluorescent intensities and improved photostabilities. AuNCs@SiO2@GQDs nanocomposites allowed specific visualization of EGFR on cancer cells.
Co-reporter:Yanling Zhai, Chengzhou Zhu, Jiangtao Ren, Erkang Wang and Shaojun Dong
Chemical Communications 2013 vol. 49(Issue 24) pp:2400-2402
Publication Date(Web):21 Dec 2012
DOI:10.1039/C2CC38292J
We report a novel design, based on a combination of lanthanide-doped upconversion nanoparticles and polyoxometalates, for electrically controlled fluorescence switches and sensitive detection of antioxidants in aqueous solution.
Co-reporter:Peng Hu, Lei Han, Chengzhou Zhu and Shao Jun Dong
Chemical Communications 2013 vol. 49(Issue 17) pp:1705-1707
Publication Date(Web):14 Dec 2012
DOI:10.1039/C2CC37734A
We have constructed a colorimetric protein assay platform based on a nanoreactor. The novel strategy presents high sensitivity and excellent performance for the detection of thrombin. The linear range is 5.58 × 10−10 to 6.50 × 10−9 M and the detection limit down to 0.19 nM is achieved.
Co-reporter:Lihua Jin, Youxing Fang, Li Shang, Yaqing Liu, Jing Li, Li Wang, Peng Hu and Shaojun Dong
Chemical Communications 2013 vol. 49(Issue 3) pp:243-245
Publication Date(Web):22 Nov 2012
DOI:10.1039/C2CC36316J
A highly robust electrochemically controlled fluorescence switch based on ultrasmall Au nanoclusters has been designed by the aid of the electrochemical redox reaction of prussian blue.
Co-reporter:Zhixue Zhou, Jinbo Zhu, Libing Zhang, Yan Du, Shaojun Dong, and Erkang Wang
Analytical Chemistry 2013 Volume 85(Issue 4) pp:2431
Publication Date(Web):January 14, 2013
DOI:10.1021/ac303440d
Endonuclease plays an important role in many biological processes, and an assay of endonuclease activity is of great significance. However, traditional methods for the assay of endonuclease activity have undesirable limitations, such as high cost, DNA-consuming and laboriousness. In the present work, a G-quadruplex-based, fluorescent assay of endonuclease activity has been developed with protoporphyrin IX (PPIX) as a signal reporter. S1 nuclease, a single strand DNA (ssDNA)-specific endonuclease, is employed as model system. In the “on” state, G-quadruplex DNA can greatly enhance the fluorescence of PPIX. However, if S1 nuclease could cleave G-quadruplex DNA into small fragments, there would be no formation of G-quadruplexes, accompanied by low emission response of PPIX. This fluorescent discrimination before or after digestion by nuclease can be used to monitor the activity of S1 nuclease. This assay is simple in design and offers a convenient protocol for homogeneous, rapid and high-throughput detection. In addition, the proposed strategy avoids complicated covalent modifications or chemical labeling, and thus offers advantages of simplicity and cost efficiency. More importantly, K+ is found to well inhibit the activity of S1 nuclease when using certain G-quadruplex DNA as substrate, and thus this system is further used for turn-on detection of K+. S1 nuclease is critical in the detection of K+ since it helps to reduce the background signal.
Co-reporter:Zhijun Zhu, Yanling Zhai, Chengzhou Zhu, Zhenxin Wang, Shaojun Dong
Electrochemistry Communications 2013 Volume 36() pp:22-25
Publication Date(Web):November 2013
DOI:10.1016/j.elecom.2013.08.024
•The peroxidase mimetics and ORR activity of PdPt NWs and NSs were investigated.•PdPt NSs possessed much better peroxidase mimetics than that of PdPt NWs.•PdPt NSs exhibited more advantageous onset potential and higher ORR activity.•PdPt NWs presented higher limiting current density.A comparative study on bimetallic alloy nanomaterials, with different dimensions (i.e., 1D nanowires and 3D nanosponges), of peroxidase mimetics and as enhanced catalysts for oxygen reduction reaction was performed. The synthesized PdPt nanosponges possessed much better oxidase and peroxidase mimetics than those of PdPt nanowires. In addition, nanosponges exhibited more advantageous onset potential and higher ORR specific activity, while nanowires presented higher limiting current density.
Co-reporter:Li Wang, Lingling Zhang, Lu Bai, Lei Han, Shaojun Dong
Electrochemistry Communications 2013 Volume 34() pp:68-72
Publication Date(Web):September 2013
DOI:10.1016/j.elecom.2013.05.019
•Synthesis of N, Co-codoped carbon electrocatalyst by using soy milk and cobalt salts.•The synthesis is simple and economic.•Co/N/C hybrid exhibits high ORR catalytic activity in alkaline solutions.•The addition of polypyrrole in the synthetic process could enhance the ORR activity.Nitrogen and cobalt codoped carbon electrocatalyst using soy milk and cobalt salts as precursors has been examined for its electrocatalytic activity toward oxygen reduction reaction (ORR). Carbon dots (C-d) were first synthesized via hydrothermal treatment of soy milk. Then, cobalt (II) nitrate was incorporated with C-d via heat treatment to generate nitrogen and cobalt codoped carbon composites (Co/C). When polypyrrole was introduced in the synthetic process, carbon composites with higher nitrogen and cobalt contents (Co/N/C) than Co/C were obtained, which exhibited high electrocatalytic activity, excellent methanol crossover effect, and good stability toward ORR in alkaline solutions.
Co-reporter:Lei Han, Chengzhou Zhu, Li Wang and Shaojun Dong
Catalysis Science & Technology 2013 vol. 3(Issue 6) pp:1501-1504
Publication Date(Web):03 Apr 2013
DOI:10.1039/C3CY20653J
Chain-like CoCu hollow nanoparticles (CHNs) were facilely obtained via a one-pot synthesis process, and we found that the obtained CHNs exhibited high catalytic ability, excellent cycle stability and facile recovery towards the catalytic reduction of p-nitrophenol to p-aminophenol.
Co-reporter:Junfeng Zhai, Daming Yong, Jing Li and Shaojun Dong
Analyst 2013 vol. 138(Issue 2) pp:702-707
Publication Date(Web):01 Nov 2012
DOI:10.1039/C2AN36160D
This work presents a new colorimetric microorganism biosensor for monitoring and detecting acute toxicity in water, where prussian blue (PB) is used as the colorimetric indicator and E. coli as the model bacterial. In this biosensor, the electron mediator, ferricyanide, accepts electrons from E. coli during respiration to produce ferrocyanide, which subsequently reacts with ferric ions to yield PB, a famous material with a blue color. Since toxicants can inhibit the respiratory activity of E. coli and then reduce the ferrocyanide and consequent PB production, toxicity can be easily detected by measuring the decrease in the production of PB induced by toxicants. Three important toxicants, 3,5-dichlorophenol (DCP), As3+, Cr6+ are tested and the detection limits are 3.2, 25, and 3.2 ppm, respectively. Moreover, we could identify the yellow green to dark green color change by naked eye even at concentrations as low as 12.5 ppm for both DCP and Cr6+. Subsequently, the acute toxicities of groundwater and south lake water are successfully determined by this sensor. This biosensor is rapid, sensitive and cost-effective, and can thus be regarded as a promising biosensor for giving an early warning of acute water toxicity.
Co-reporter:Dengbin Yu, Junfeng Zhai, Daming Yong and Shaojun Dong
Analyst 2013 vol. 138(Issue 11) pp:3297-3302
Publication Date(Web):28 Mar 2013
DOI:10.1039/C3AN36907B
Determining and monitoring toxicity of chemicals in water are very important for human health and country security. Electrochemical measurement of respiratory chain activity is a rapid and reliable screening of the toxicity towards microorganisms. Here, we report a rapid and sensitive toxicity bioassay using p-benzoquinone as the artificial electron mediator and Escherichia coli as the test organism. Four heavy metal ions, Cu2+, Ag+, Hg2+ and Co2+, are tested as the model toxicants, and the corresponding 50% respiration inhibition concentrations (IC50) are determined to be 0.95, 8.14, 11.69 and 42.76 mg L−1, respectively. Based on the IC50 values, the descending order of toxicity is: Cu2+ > Ag+ > Hg2+ > Co2+. The presented bioassay not only provides a good foundation for further toxicity tests using E. coli, but also the potential for expanding the technique to utilize other bacteria with complementary toxicity responses, thereby allowing use of the bioassay in a wide range of applications.
Co-reporter:Lei Han, Chengzhou Zhu, Peng Hu and Shaojun Dong
RSC Advances 2013 vol. 3(Issue 31) pp:12568-12570
Publication Date(Web):06 Jun 2013
DOI:10.1039/C3RA42431F
In this work, Au@TiO2 core–shell nanocomposites have been successfully prepared by a one-pot method through the combination of the reverse micelle technique with the redox reaction between Au(III) and Ti(III) for the first time, and showed excellent stability towards the catalytic reduction of 4-nitrophenol.
Co-reporter:Chengzhou Zhu;Shaojun Guo; Shaojun Dong
Chemistry - A European Journal 2013 Volume 19( Issue 3) pp:1104-1111
Publication Date(Web):
DOI:10.1002/chem.201202909
Abstract
We have demonstrated a rapid and general strategy to synthesize novel three-dimensional PdPt bimetallic alloy nanosponges in the absence of a capping agent. Significantly, the as-prepared PdPt bimetallic alloy nanosponges exhibited greatly enhanced activity and stability towards ethanol/methanol electrooxidation in an alkaline medium, which demonstrates the potential of applying these PdPt bimetallic alloy nanosponges as effective electrocatalysts for direct alcohol fuel cells. In addition, this simple method has also been applied for the synthesis of AuPt, AuPd bimetallic, and AuPtPd trimetallic alloy nanosponges. The as-synthesized three-dimensional bimetallic/trimetallic alloy nanosponges, because of their convenient preparation, well-defined sponge-like network, large-scale production, and high electrocatalytic performance for ethanol/methanol electrooxidation, may find promising potential applications in various fields, such as formic acid oxidation or oxygen reduction reactions, electrochemical sensors, and hydrogen-gas sensors.
Co-reporter:Changyu Liu, Shaojun Dong
Talanta 2013 Volume 109() pp:147-151
Publication Date(Web):15 May 2013
DOI:10.1016/j.talanta.2013.02.006
A tubular biofilm reactor (BFR) based online biochemical oxygen demand prototype was applied in Taihu Lake, China. Municipal tap water was used instead of conventional phosphate buffer as blank solution to avoid phosphate pollution. The background organic compounds in municipal tap water were taken into account and they were validated to result in negative deviation to accuracy. The microbial endogenous respiration was experimentally validated to be sensitive to salt ionic strength, and municipal tap water as blank was thought to generate positive deviation to accuracy. The system was continuously operated over 2 months without man intervention, and the automated monitoring data agreed well with that of the conventional BOD5 methods. The BFR resisted the frequent measurements with samples of high turbidity, and the BOD monitoring data indicated the index of biodegradable organic compounds of Taihu Lake was accorded with the second class described in the environmental quality standard of surface water. Analyzed together with permanganate index on site, Taihu Lake was revealed to be of good capacity of self cleaning. Importantly, field application study of new BOD method made it more objective in evaluating its applicability, and could provide practical information and useful improvements in the process of commercializing.Highlights► A biofilm reactor based protype was used for determination of BOD. ► The protype needs only tap water to operate and requires no chemical reagent. ► The organic compounds in municipal tap water brought a negative deviation. ► Inorganic ions in low concentrations influenced the microbial endogenous respiration. ► The automated monitoring showed that BOD of Taihu Lake maintained at a low level.
Co-reporter:Changyu Liu, Huijun Zhao, Shan Gao, Jianbo Jia, Limin Zhao, Daming Yong, Shaojun Dong
Biosensors and Bioelectronics 2013 Volume 45() pp:213-218
Publication Date(Web):15 July 2013
DOI:10.1016/j.bios.2013.01.041
We reported a reagent-free tubular biofilm reactor (BFR) based analytical system for rapid online biochemical oxygen demand (BOD) determination. The BFR was cultivated using microbial seeds from activated sludge. It only needs tap water to operate and does not require any chemical reagent. The analytical performance of this reagent-free BFR system was found to be equal to or better than the BFR system operated using phosphate buffer saline (PBS) and high purity deionized water. The system can readily achieve a limit of detection of 0.25 mg O2 L−1, possessing superior reproducibility, and long-term operational and storage stability. More importantly, we confirmed for the first time that the BFR system is capable of tolerating common toxicants found in wastewaters, such as 3,5-dichlorophenol and Zn(II), Cr(VI), Cd(II), Cu(II), Pb(II), Mn(II) and Ni(II), enabling the method to be applied to a wide range of wastewaters. The sloughing and clogging are the important attributes affecting the operational stability, hence, the reliability of most online wastewater monitoring systems, which can be effectively avoided, benefiting from the tubular geometry of the reactor and high flow rate conditions. These advantages, coupled with simplicity in device, convenience in operation and minimal maintenance, make such a reagent-free BFR analytical system promising for practical BOD online determination.Highlights► A biofilm reactor was used for online determination of biochemical oxygen demand. ► The system needs only tap water to operate and requires no chemical reagent. ► The biofilm reactor exhibits a high tolerance to common toxicants. ► The system showed the limit of detection as low as 0.25 mg O2 L−1. ► The simplicity of device made this method promising for online applications.
Co-reporter:Changyu Liu, Jianbo Jia, Shaojun Dong
Biosensors and Bioelectronics 2013 Volume 42() pp:1-4
Publication Date(Web):15 April 2013
DOI:10.1016/j.bios.2012.10.018
We reported a biofilm reactor (BFR) based analytical system for real-time biochemical oxygen demand (BOD) monitoring. It does not need a blank solution and other chemical reagents to operate. The initial dissolved oxygen (DO) in sample solution was measured as blank, while DO in the BFR effluent was measured as response. The DO difference obtained before and after the sample solution flowed through the BFR was regarded as an indicator of real-time BOD. The analytical performance of this reagent-free BFR system was equal to the previous BFR system operated using phosphate buffer saline (PBS) and high purity deionized water in reproducibility, accuracy and long-term stability. Besides, this method embraces many notable advantages, such as no secondary pollution. Additionally, the sample solutions are free from temperature controlling and air-saturation before injection. Significantly, this is a real-time BOD analysis method. This method was successfully carried out in a simulated emergency, and the obtained results agreed well with conventional BOD5. These advantages, coupled with simplicity in device, convenience in operation and minimal maintenance, make such a reagent-free BFR analytical system promising for practical BOD real-time warning.Highlights► A biofilm reactor together with two oxygen probes was used for real-time analysis of biochemical oxygen demand. ► The system does not need blank solution to operate and requires no chemical reagent. ► This analytical method was validated to be free from washing. ► Organic residue was never a question in this method. ► The simplified procedures made it promising for real-time BOD warning/determination.
Co-reporter:Baohua Lou, Chaogui Chen, Zhixue Zhou, Lingling Zhang, Erkang Wang, Shaojun Dong
Talanta 2013 Volume 105() pp:40-45
Publication Date(Web):15 February 2013
DOI:10.1016/j.talanta.2012.11.062
In this paper, conducting polymer film modified electrodes were applied to fabricate paper-based chips (PCs), and different concentrations of chloride ions (Cl−) in water can be selectively detected based on the potential response towards Cl−. The three-electrode system was screen-printed on paper and the polypyrrole (PPy) film doped with Cl− was electrochemically polymerized on working electrodes through cyclic voltammetry in aqueous solution. Open circuit potential-time method was used to measure the potential response. Based on such PCs, Cl− can be selectively detected in the range of 10−7–10−2 M. Moreover, such PCs were utilized for Cl− analysis in real water samples and resulted in good results with recoveries between 113% and 124%. Besides, following the strategy we also employed this method to detect F− in water to demonstrate its general applicability. In view of its novelty, simplicity, sensitivity and low price, such PCs will potentially be utilized for the monitoring of anions in the environment, and our method made a start for the application of CMEs to PCs to design electrochemical sensors.Highlights► This novel paper-based chloride ion sensor is easy to manufacture and low-cost. ► The potential response is fast, stable, and sensitive. ► Do not need complicated and expensive instruments. ► The sensor is portable and disposable.
Co-reporter:Chengzhou Zhu;Shaojun Guo
Advanced Materials 2012 Volume 24( Issue 17) pp:2326-2331
Publication Date(Web):
DOI:10.1002/adma.201104951
Co-reporter:Lei Han, Ping Wang and Shaojun Dong
Nanoscale 2012 vol. 4(Issue 19) pp:5814-5825
Publication Date(Web):30 Jul 2012
DOI:10.1039/C2NR31699D
Carbon nanomaterials based nanocomposites have gained increasing interest owing to their potential applications in many aspects, such as photocatalysis, solar cells, solar fuel, etc. Graphene, as a new type of carbon nanomaterial, has attracted consideration attention due to its unique two-dimensional conjugated structure and electronic properties. In this feature article, we cover recent advances in the applications of graphene-based photoactive nanocomposites in environmental remediation and energy conversion, including photocatalytic degradation of organic contaminants, photoelectrochemical solar cells, and solar fuel production. Finally, the perspectives of the challenges and opportunities in this emerging area are also discussed.
Co-reporter:Chengzhou Zhu, Lei Han, Peng Hu and Shaojun Dong
Nanoscale 2012 vol. 4(Issue 5) pp:1641-1646
Publication Date(Web):30 Jan 2012
DOI:10.1039/C2NR11625A
We demonstrated a simple, in situ reduction route to the synthesis of two-dimensional graphene oxide/SiO2 (GSCN) hybrid nanostructures consisting of Au nanoparticles (Au NPs) supported on the both sides of GSCN. The as-prepared GSCN/Au NPs hybrid nanomaterials exhibited good catalytic activity for the reduction of 4-nitrophenol. This approach provided a useful platform based on GO hybrid nanomaterials for the fabrication of GSCN/Au NPs hybrid nanomaterials, which could be very useful in catalytic applications.
Co-reporter:Chengzhou Zhu, Shaojun Guo and Shaojun Dong
Journal of Materials Chemistry A 2012 vol. 22(Issue 30) pp:14851-14855
Publication Date(Web):28 Jun 2012
DOI:10.1039/C2JM32663A
Using ultrathin, high aspect ratio Te nanowires as a template, we demonstrated a facile method to synthesize high-quality AuPtPd trimetallic alloy nanowires in aqueous solution at room temperature within one hour. More importantly, the obtained AuPtPd trimetallic alloy nanowires exhibited significantly enhanced activity towards ethanol electrooxidation in alkaline medium, demonstrating the potential of applying these Pd-based alloy nanowires as effective electrocatalysts for direct alcohol fuel cells. Considering the important role of one-dimensional trimetallic alloy nanostructures in catalytic systems, the present AuPtPd alloy nanowires may also find applications in other fields, such as fuel cells (formic acid, methanol oxidation and oxygen reduction reaction) and electrochemical biosensors.
Co-reporter:Chengzhou Zhu, Junfeng Zhai, Dan Wen and Shaojun Dong
Journal of Materials Chemistry A 2012 vol. 22(Issue 13) pp:6300-6306
Publication Date(Web):21 Feb 2012
DOI:10.1039/C2JM16699B
We introduce a facile method for the construction of graphene oxide/polypyrrole (GO/PPy) nanocomposites via one–step coelectrodeposition. In this process, the relatively large anionic GO serves as a weak electrolyte and is entrapped in the PPy nanocomposites during the electropolymerization of pyrrole, and also acts as an effective charge-balancing dopant within the PPy film. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) results demonstrate that the GO/PPy nanocomposites are successfully synthesized. The obtained GO/PPy nanocomposites exhibit good electrochemical properties and cycling performance, indicating a synergistic effect of PPy and GO. Taking its higher capacitance, lower cost and shorter processing time into consideration, GO may be a good choice for the fabrication of electrochemical supercapacitors based on conducting polymer nanocomposites. It should be noted that this coelectrodeposition is also applicable for the graphene oxide/poly[3,4-ethylenedioxythiophene] (GO/PEDOT) nanocomposites. Moreover, this facile and effective approach for the synthesis of GO/conducting polymer nanocomposites further extends the application of GO and should be very promising for the fabrication of inexpensive, high-performance electrochemical supercapacitors.
Co-reporter:Chengzhou Zhu, Junfeng Zhai and Shaojun Dong
Chemical Communications 2012 vol. 48(Issue 75) pp:9367-9369
Publication Date(Web):19 Jun 2012
DOI:10.1039/C2CC33844K
We demonstrated a facile and green approach to synthesize bifunctional fluorescent carbon nanodots via soy milk, which not only showed favorable photoluminescent properties, but also exhibited good electrocatalytic activity towards oxygen reduction reaction.
Co-reporter:Lei Han, Lu Bai, Chengzhou Zhu, Yizhe Wang and Shaojun Dong
Chemical Communications 2012 vol. 48(Issue 49) pp:6103-6105
Publication Date(Web):30 Apr 2012
DOI:10.1039/C2CC32168H
A new light-driven, membraneless and mediatorless glucose–air biofuel cell combining a TiO2 nanotube photoanode with an enzyme-modified biocathode has been successfully constructed. Upon UV light illumination, the open-circuit voltage and the maximum power density of the cell reach 1.00 V and 47 μW cm−2, respectively.
Co-reporter:Yan Du, Shaojun Guo, Haixia Qin, Shaojun Dong and Erkang Wang
Chemical Communications 2012 vol. 48(Issue 6) pp:799-801
Publication Date(Web):03 Nov 2011
DOI:10.1039/C1CC15303J
A new electrochemical label-free biosensor based on target-induced conjunction of a split aptamer as new chiral selector for oligopeptide using graphene–mesoporous silica–gold NP hybrids (GSGHs) as magnified sensing platform is firstly reported, which showed high sensitivity and selectivity for the detection of D-vasopressin (D-VP).
Co-reporter:Li Wang, Miao Xu, Lei Han, Ming Zhou, Chengzhou Zhu, and Shaojun Dong
Analytical Chemistry 2012 Volume 84(Issue 17) pp:7301
Publication Date(Web):July 26, 2012
DOI:10.1021/ac300521d
Graphene (GN), a two-dimensional and one-atom thick carbon sheet, is showing exciting applications because of its unique morphology and properties. In this work, a new electrochemical biosensing platform by taking advantage of the ultrahigh electron transfer ability of GN and its unique GN/ssDNA interaction was reported. Adenosine triphosphate binding aptamer (ABA) immobilized on Au electrode could strongly adsorb GN due to the strong π–π interaction and resulted in a large decrease of the charge transfer resistance (Rct) of the electrode. However, the binding reaction between ABA and its target adenosine triphosphate (ATP) inhibited the adsorption of GN, and Rct could not be decreased. On the basis of this, we developed a new GN-based biosensing platform for the detection of small molecule ATP. The experimental results confirmed that the electrochemical aptasensor we developed possessed a good sensitivity and high selectivity for ATP. The detection range for ATP was from 15 × 10–9 to 4 × 10–3 M. The method here was label-free and sensitive and did not require sophisticated fabrication. Furthermore, we can generalize this strategy to detect Hg2+ using a thymine (T)-rich, mercury-specific oligonucleotide. Therefore, we expected that this method may offer a promising approach for designing high-performance electrochemical aptasensors for the sensitive and selective detection of a spectrum of targets.
Co-reporter:Lingling Zhang, Ming Zhou, and Shaojun Dong
Analytical Chemistry 2012 Volume 84(Issue 23) pp:10345
Publication Date(Web):November 5, 2012
DOI:10.1021/ac302414a
Acetaldehyde is recognized as a type of organic environmental pollutant all over the world, which makes the sensitive, rapid, simple and low-cost detection of acetaldehyde urgent and significant. Inspired by the biological principle of feedback modulation, we have developed a novel and effective self-powered device for aqueous acetaldehyde detection. In this self-powered device, an ethanol/air enzymatic biofuel cell (BFC) served as the core component, which showed the maximum power output density of 28.5 μW cm–2 at 0.34 V and the open circuit potential (Voc) of 0.64 V. The product of ethanol oxidation, acetaldehyde, would counteract the electrocatalysis at the bioanode and further decrease the power output of the BFC. Based on such principles, the fabricated acetaldehyde sensor exhibited excellent selectivity with wide linear range (5–200 μM) and low detection limit (1 μM), which conforms to the criteria provided by the World Health Organisation (WHO). In addition, the sensor fabrication is simple, fast, inexpensive, and user-friendly, and the detection process is convenient, efficient, and time-saving, requiring no complicated equipment. These make such self-powered acetaldehyde sensors feasible and practical for detecting aqueous acetaldehyde, particularly in the field of quality control and monitoring aimed at water resource protection.
Co-reporter:Junfeng Zhai, Ling Liu, Daming Yong, Dan Li and Shaojun Dong
Analytical Methods 2012 vol. 4(Issue 11) pp:3849-3854
Publication Date(Web):04 Sep 2012
DOI:10.1039/C2AY25899D
In this work, we develop a reconfigured colorimetric bioassay for direct toxicity assessment (DTA) of toxic chemicals in water based on neutral red (NR) as a colorimetric indicator. Confocal laser scanning microscopy and UV-vis absorption spectroscopy are employed to prove the feasibility of the proposed assays using P. fluorescens as the model microorganism. The presence of toxicants can damage cells, and this results in an enhanced adsorption of NR by the cells. This fact provides a new strategy for DTA of toxic chemicals by comparing the absorption peak intensities of residual NR after incubation in the presence of toxicants. Four important toxicants such as 3,5-dichlorophenol (DCP), As3+, Hg2+ and Cr6+ are tested, and the toxicity order is DCP > Hg2+ > Cr6+ > As3+, which is identical with that obtained by the ferricyanide-mediated toxicity alerter (FM-tox) assay. The RC50 value of DCP is estimated to be 12.5 mg L−1, which is comparable with that of other DTA assays. The responses of E. coli and BOD seed (multi-species cultures) to DCP are further examined successfully, suggesting this NR based colorimetric assay may be a general one to measure the response of microorganisms to toxic chemicals. The low cost of NR, easy and simple operation procedure and reliable results make this assay a promising one in DTA.
Co-reporter:Zhixue Zhou, Chengzhou Zhu, Jiangtao Ren, Shaojun Dong
Analytica Chimica Acta 2012 740() pp: 88-92
Publication Date(Web):31 August 2012
DOI:10.1016/j.aca.2012.06.032
Using the remarkable difference in the affinity of graphene oxide (GO) with double strand DNA (dsDNA) and short DNA fragments, we report for the first time a GO-based nonrestriction nuclease responsive system. Our system was composed of GO and a fluorescent dye fluorescein amidite (FAM)-labeled dsDNA substrate (F-dsDNA). At first, the fluorescence of this F-dsDNA substrate was quenched upon addition of GO. When nuclease was added to the mixture of dsDNA and GO, hydrolysis of dsDNA was initiated and small DNA fragments were produced. As a result, the short FAM-linked DNA fragments were released from GO due to the weak affinity of GO with short DNA fragments, and the fluorescence got a restoration. At present, many sensing systems are based on the fact that GO prefers to bind long single strand DNA (ssDNA) over dsDNA or short ssDNA. As for our system, GO has a prior binding with dsDNA over short DNA fragments. Compared with previous methods, this assay platform has some advantages. First, since GO can be prepared in large quantities from graphite available at very low cost, this method shows advantages of simplicity and cost efficiency. Besides, the proposed GO-based nuclease assay provides high sensitivity due to the super quenching capacity of GO. Using deoxyribonuclease I (DNase I) as a model system, DNase I activity can be quantitatively analyzed by the velocity of the enzymatic reaction, and 1.75 U mL−1 DNase I can be significantly detected. Moreover, the fluorescent intensity with various concentrations of nuclease becomes highly discriminating after 3–8 min. Thus, it is possible to detect nuclease activity within 3–8 min, which demonstrates another advantage of quick response of the present system. Finally, use of dsDNA as substrate, our method can achieve real-time nuclease activity/inhibition assay, which is time-saving and effortless.Graphical abstractHighlights► A novel graphene-based real-time fluorescent assay of deoxyribonuclease I (DNase I) activity and inhibition is developed. ► DNase I activity can be quantitatively analyzed by the velocity of the enzymatic reaction, and 1.75 U mL−1 DNase I can be significantly detected. ► Crystal violet (CV) is found to inhibit DNase I with IC50 values of 0.35 μM.
Co-reporter:Li Wang, Jinbo Zhu, Lei Han, Lihua Jin, Chengzhou Zhu, Erkang Wang, and Shaojun Dong
ACS Nano 2012 Volume 6(Issue 8) pp:6659
Publication Date(Web):July 23, 2012
DOI:10.1021/nn300997f
In this work, a GO/aptamer system was constructed to create multiplex logic operations and enable sensing of multiplex targets. 6-Carboxyfluorescein (FAM)-labeled adenosine triphosphate binding aptamer (ABA) and FAM-labeled thrombin binding aptamer (TBA) were first adsorbed onto graphene oxide (GO) to form a GO/aptamer complex, leading to the quenching of the fluorescence of FAM. We demonstrated that the unique GO/aptamer interaction and the specific aptamer–target recognition in the target/GO/aptamer system were programmable and could be utilized to regulate the fluorescence of FAM via OR and INHIBIT logic gates. The fluorescence changed according to different input combinations, and the integration of OR and INHIBIT logic gates provided an interesting approach for logic sensing applications where multiple target molecules were present. High-throughput fluorescence imagings that enabled the simultaneous processing of many samples by using the combinatorial logic gates were realized. The developed logic gates may find applications in further development of DNA circuits and advanced sensors for the identification of multiple targets in complex chemical environments.Keywords: aptamer; ATP; graphene; logic gates; multiplex detection; thrombin
Co-reporter:Ling Liu, Shengsen Zhang, Li Xing, Huijun Zhao, Shaojun Dong
Talanta 2012 Volume 93() pp:314-319
Publication Date(Web):15 May 2012
DOI:10.1016/j.talanta.2012.02.039
In this paper, we proposed a method by using co-immobilized Escherichia coli (E. coli) as a biocatalyst and neutral red (NR) as an artificial electronic acceptor to modify glassy carbon electrode (GCE) for biochemical oxygen demand (BOD) measurement. Two different modification approaches of GCE were utilized and compared. In one approach, NR was electropolymerized on the surface of GCE, and E. coli cells were mixed with grafting copolymer PVA-g-PVP (briefly gPVP) and covered on NR polymer film to obtain a (gPVP/E. coli)/PNR/GCE. In the second approach, both NR and E. coli cells were mixed with the copolymer gPVP and modified GCE, after drying, which was electrochemically treated similar as above for obtaining a (gPVP/E. coli/NR)p/GCE. Based on the electrochemical evaluation, the performance of the latter was better, which may be caused by that the NR deposited on the surface of E. coli resulting in a good electron transport and permeability of cells membrane. To develop the results obtained at (gPVP/E. coli/NR)p/GCE further, the pretreatment by TiO2 nanotubes arrays (TNTs) was employed, and different effects on samples of GGA, OECD, urea and real wastewater were evaluated. These results suggest that the present method holds a potential application for rapid BOD biosensor.Highlights► Co-immobilized microbes and mediator were used in BODMed method. ► Modifying GCE (gPVP/E. coli/NR)p/GCE and (gPVP/E. coli)/PNR/GCE were compared. ► TNTs pretreatments were utilized for enhancing electrochemical signal. ► Different effects of TNTs pretreatments for OECD, GGA, urea and real wastewater.
Co-reporter:Lu Bai, Dan Wen, Jianyuan Yin, Liu Deng, Chengzhou Zhu, Shaojun Dong
Talanta 2012 Volume 91() pp:110-115
Publication Date(Web):15 March 2012
DOI:10.1016/j.talanta.2012.01.027
An excellent electrochemical sensing platform has been designed by combining the huge specific surface area of carbon nanotubes (CNTs) and the remarkable conductivity of ionic liquid (IL). IL can easily untangle CNTs bundles and disperse CNTs by itself under grinding condition due to the π–π interaction between CNTs and IL. The resulting nanocomposites showed an augmentation on the voltammetric and amperometric behaviors of electrocatalytic activity toward O2 and NADH. Therefore, such an efficient platform was developed to fabricate mediator-free oxygen sensor and glucose biosensor based on glucose dehydrogenase (GDH). O2 could be determined in the range of zero to one hundred percent of O2 content with the detection limit of 126 μg L−1 (S/N = 3). The glucose biosensor which was constructed by entrapping GDH into chitosan on the nanocomposites modified glassy carbon electrode surface, exhibited good electrocatalytic oxidation toward glucose with a detection limit of 9 μM in the linear range of 0.02–1 mM. We also applied the as-prepared sensors to detect oxygen and glucose in real blood samples and acquired satisfied results.Highlights► An excellent sensing platform based on CNTs and IL has been designed. ► The CNTs-IL nanocomposites enhanced electrocatalytic activity of O2 and NADH. ► Mediator-free O2 sensor and glucose biosensor was developed. ► The as-prepared sensors were applied in real blood samples.
Co-reporter:Peng Hu, Chengzhou Zhu, Lihua Jin, Shaojun Dong
Biosensors and Bioelectronics 2012 Volume 34(Issue 1) pp:83-87
Publication Date(Web):15 April 2012
DOI:10.1016/j.bios.2012.01.022
We report here a graphene oxide (GO)-based fluorescent aptasensor for adenosine detection by employing exonuclease III (Exo III) as a signal amplifying element. In the absence of adenosine, the adenosine aptamers hybridized with the complementary DNA (cDNA), and the Exo III could not cleave the single-strand signal probes labeled with carboxylfluorescein (FAM) at its 5′ ends. When the graphene oxide was finally added, it could strongly adsorb the single-strand signal probes and quenched the fluorophore effectively. In the presence of adenosine, the aptamers associated with the targets, which led to the formation of duplex DNAs between the cDNAs and the signal probes. The Exo III thereafter could digest the duplex DNAs from 3′ blunt terminus of signal probes, liberating the fluorophore. Upon adding the GO, the fluorophore could not be adsorbed and quenched. By coupling cyclic enzymatic cleavage, a remarkable fluorescent increase was obtained. Due to the specific recognition ability of the aptamer for the target and the powerful quenching property of GO for signal probe, this proposed approach has a good selectivity and high sensitivity for adenosine. In the optimum conditions described, >100% signal enhancement was achieved and a limit of detection as low as 1 nM was obtained, which is lower than those of commonly used fluorescent aptamer sensors. Moreover, the biosensor exhibited an ultrahigh sensitivity and held a versatile platform for clinical diagnostics, molecular biology and drug developments.Highlights► We report here a novel amplified fluorescent aptasensor for adenosine detection. ► The sensor utilizes exonuclease III (Exo III) as a signal amplifying element and graphene oxide as fluorescence quencher. ► The fluorescent sensor held a versatile platform for clinical diagnostics, molecular biology and drug developments.
Co-reporter:Changyu Liu, Huijun Zhao, Lijie Zhong, Chang Liu, Jianbo Jia, Xiaolong Xu, Ling Liu, Shaojun Dong
Biosensors and Bioelectronics 2012 Volume 34(Issue 1) pp:77-82
Publication Date(Web):15 April 2012
DOI:10.1016/j.bios.2012.01.020
A new analytical approach utilizing a biofilm reactor (BFR) for rapid online determination of biochemical oxygen demand (BOD) was proposed and experimentally validated. The BFR was fabricated via a cultivation process using naturally occurring microbial seeds from locally collected wastewaters. The resultant BFR displays a remarkable rate of biodegradation towards a wide spectrum of organic substrates, capable of degrading over 20% of biodegradable organic substrates within 100 s. More importantly, the BFR exhibits a superior indiscriminative biodegradation feature, enabling a precise prediction of BOD values of total biodegradable organics based on experimentally determined BOD values from partial degradation processes without a need for on-going calibration. The proposed approach was systematically validated using a range of individual organic substrates, their mixtures, synthetic samples and wastewaters. Highly significant linear correlations between the BFR and the standard BOD5 methods were obtained from diversified synthetic samples (r = 0.988, p = 0.000, n = 45) and wastewaters (r = 0.983, p = 0.000, n = 40). Near unity slope values of the principal axis of the correlation ellipse were obtained from all tested samples, suggesting both methods were essentially measuring the same BOD value. The reported method could be a useful online monitoring tool for determination of biodegradable organic pollutants.Highlights► A biofilm reactor was developed for rapid online biodegradable organic pollutants determination. ► The biofilm reactor could indiscriminately biodegrade 20% of organic pollutants within 99 s. ► A new analytical signal quantification method was proposed and experimentally validated. ► The developed method embraces the inherent advantages of both rapid BOD and BOD5 method.
Co-reporter:Zhixue Zhou, Yan Du, Libing Zhang, Shaojun Dong
Biosensors and Bioelectronics 2012 Volume 34(Issue 1) pp:100-105
Publication Date(Web):15 April 2012
DOI:10.1016/j.bios.2012.01.024
A novel G-quadruplex DNAzyme molecular beacon (G-DNAzymeMB) strategy is developed for assays of target DNA and restriction endonuclease. The detection system consists of G-DNAzymeMB strand and a blocker DNA by using the fluorescence of 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA) catalyzed by G-DNAzymeMB as a signal reporter. G-DNAzymeMB exhibits peroxidase activity in its free hairpin structure, and forms a catalytically inactive hybrid when hybridized with blocker DNA. Upon displacement of blocker DNA by target DNA or cleavage by restriction endonuclease, G-DNAzymeMB is released and two lateral portions of G-DNAzymeMB form a G-quadruplex structure, resulting in the recovery of catalytic activity which acts as a cofactor to catalyze H2O2-mediated oxidation of H2DCFDA. For DNA detection system, exonuclease III (Exo III)-catalyzed amplification strategy is introduced to improve the sensitivity and target DNA could be detected as low as 0.1 pM. With respect to restriction endonuclease detection system, 0.1 U/mL EcoRI endonuclease could be detected and this method could be easily transported to other restriction endonuclease analysis by simply changing the recognition sequence. These results demonstrate that the proposed G-DNAzymeMB strategy could be used as a label-free, simple, sensitive and cost-effective approach in analysis of target DNA and restriction endonuclease.Highlights► A novel G-quadruplex DNAzyme molecular beacon (G-DNAzymeMB) strategy is developed for assays of target DNA and restriction endonuclease. ► For DNA detection system, exonuclease III-catalyzed amplification strategy is introduced to improve the sensitivity and target DNA could be detected as low as 0.1 pM. ► With respect to restriction endonuclease detection system, 0.1 U/mL EcoRI endonuclease could be detected and this method could be easily transported to other restriction endonuclease analysis by simply changing the recognition sequence.
Co-reporter:Lingling Zhang, Ming Zhou, Dan Wen, Lu Bai, Baohua Lou, Shaojun Dong
Biosensors and Bioelectronics 2012 35(1) pp: 155-159
Publication Date(Web):
DOI:10.1016/j.bios.2012.02.035
Co-reporter:Shaojun Guo and Shaojun Dong
Chemical Society Reviews 2011 vol. 40(Issue 5) pp:2644-2672
Publication Date(Web):31 Jan 2011
DOI:10.1039/C0CS00079E
The emergence of graphene nanosheet (GN, 2010 Nobel Prize for Physics) has recently opened up an exciting new field in the science and technology of two-dimensional (2D) nanomaterials with continuously growing academic and technological impetus. GN exhibits unique electronic, optical, magnetic, thermal and mechanical properties arising from its strictly 2D structure and thus has many important technical applications. Actually, GN-based materials have enormous potential to rival or even surpass the performance of carbon nanotube-based counterparts, given that cheap, large-scale production and processing methods for high-quality GN become available. Therefore, the studies on GN in the aspects of chemistry, physical, materials, biology and interdisciplinary science have been in full flow in the past five years. In this critical review, from the viewpoint of chemistry and materials, we will cover recent significant advances in synthesis, molecular engineering, thin film, hybrids, and energy and analytical applications of the “star-material” GN together with discussion on its major challenges and opportunities for future GN research (315 references).
Co-reporter:Dan Wen, Xiaolong Xu and Shaojun Dong
Energy & Environmental Science 2011 vol. 4(Issue 4) pp:1358-1363
Publication Date(Web):04 Mar 2011
DOI:10.1039/C0EE00080A
We have demonstrated a miniature biofuel cell (BFC) with single-walled carbon nanohorn (SWNH)-modified carbon fiber microelectrodes (CFMEs) as the substrate for the first time. The bioanode was constructed by using glucose dehydrogenase (GDH) as the biocatalyst on SWNH-modified CFMEs, where a highly efficient and stably confined electrocatalyst for the oxidation of the NADH co-factor of GDH was beforehand immobilized. Similarly, an electrically contacted bilirubin oxidase (BOD)–SWNHs/CFME was prepared as the biocathode, which showed direct bioelectrocatalytic functions for the reduction of O2 to H2O. The maximum power output of the cell was 140 μW cm−2 at 0.51 V. Most interestingly, the present glucose/air BFC can directly harvest energy from different kinds of soft drinks, which could promise potential applications of the BFC as portable power sources.
Co-reporter:Ming Zhou and Shaojun Dong
Accounts of Chemical Research 2011 Volume 44(Issue 11) pp:1232
Publication Date(Web):August 3, 2011
DOI:10.1021/ar200096g
Over the past decade, researchers have devoted considerable attention to the integration of living organisms with electronic elements to yield bioelectronic devices. Not only is the integration of DNA, enzymes, or whole cells with electronics of scientific interest, but it has many versatile potential applications. Researchers are using these ideas to fabricate biosensors for analytical applications and to assemble biofuel cells (BFCs) and biomolecule-based devices. Other research efforts include the development of biocomputing systems for information processing.In this Account, we focus on our recent progress in engineering at the bioelectrochemical interface (BECI) for the rational design and construction of important bioelectronic devices, ranging from electrochemical (EC-) biosensors to BFCs, and self-powered logic biosensors. Hydrogels and sol–gels provide attractive materials for the immobilization of enzymes because they make EC-enzyme biosensors stable and even functional in extreme environments. We use a layer-by-layer (LBL) self-assembly technique to fabricate multicomponent thin films on the BECI at the nanometer scale. Additionally, we demonstrate how carbon nanomaterials have paved the way for new and improved EC-enzyme biosensors. In addition to the widely reported BECI-based electrochemical impedance spectroscopy (EIS)-type aptasensors, we integrate the LBL technique with our previously developed “solid-state probe” technique for redox probes immobilization on electrode surfaces to design and fabricate BECI-based differential pulse voltammetry (DPV)-type aptasensors. BFCs can directly harvest energy from ambient biofuels as green energy sources, which could lead to their application as simple, flexible, and portable power sources. Porous materials provide favorable microenvironments for enzyme immobilization, which can enhance BFC power output. Furthermore, by introducing aptamer-based logic systems to BFCs, such systems could be applied as self-powered and intelligent aptasensors for the logic detection. We have developed biocomputing keypad lock security systems which can be also used for intelligent medical diagnostics.BECI engineering provides a simple but effective approach toward the design and fabrication of EC-biosensors, BFCs, and self-powered logic biosensors, which will make essential contributions in the development of creative and practical bioelectronic devices. The exploration of novel interface engineering applications and the creation of new fabrication concepts or methods merit further attention.
Co-reporter:Shaojun Guo and Shaojun Dong
Journal of Materials Chemistry A 2011 vol. 21(Issue 46) pp:18503-18516
Publication Date(Web):04 Oct 2011
DOI:10.1039/C1JM13228H
Graphene, a new material for which the Noble prize was won, has received increasing attention due to its unique physicochemical properties, such as a high surface area, excellent conductivity, a high mechanical strength, and good biocompatibility. In particular, in the last two years there has been explosive growth in studies relating to the use of graphene and its derivatives as enhanced materials or carriers for probes and recognition elements in the development of high-performance analytical devices. In this feature article, we will highlight recent important progress in the construction of graphene and its derivative-based high-performance analytical sensors. First, recent research efforts on the design of new electrochemical sensors, including amperometry, electrochemical luminescence (ECL), field-effect transistor (FET), electrochemical impedance, photoelectrochemical and surface plasmon resonance (SPR) electrochemical sensors are described. Then, we will move on to discuss more modish optical sensors, such as fluorescent, colorimetric and surface enhanced Raman spectroscopy (SERS) sensors. Finally, we conclude with a look at the future challenges and prospects of graphene and its derivative-related analytical devices.
Co-reporter:Chengzhou Zhu, Ping Wang, Li Wang, Lei Han and Shaojun Dong
Nanoscale 2011 vol. 3(Issue 10) pp:4376-4382
Publication Date(Web):09 Sep 2011
DOI:10.1039/C1NR10634A
In this paper, we reported a simple, aqueous-phase route to the synthesis of two-dimensional graphene/SnO2 composite nanosheets (GSCN) hybrid nanostructures consisting of 5 nm Pt nanoparticles supported on the both sides of GSCN. Functional two-dimensional GSCN were obtained through the reduction of graphene oxide (GO) using SnCl2 in the presence of polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA). The main advantages of this preparation are that the reduction of GO, the formation of SnO2 and the functionalization of GSCN were achieved simultaneously through one-pot reaction. GSCN/Pt ternary hybrid nanomaterials were generated by in situreduction of negatively charged PtCl62− precursors adsorbed on the positively charged surface of GSCN through electrostatic attraction. The as-synthesized GSCN/Pt ternary hybrid nanomaterials exhibited high cycle stabilization during the catalytic reduction of p–nitrophenol into p-aminophenol by NaBH4. Additionally, our approach is expected to extend to other hybrid nanomaterials. We believe that the obtained GSCN/Pt ternary hybrid nanomaterials have great potential for applications in other field, such as electrochemical energy storage, sensors, and so on.
Co-reporter:Lei Han, Ping Wang, Chengzhou Zhu, Yueming Zhai and Shaojun Dong
Nanoscale 2011 vol. 3(Issue 7) pp:2931-2935
Publication Date(Web):25 May 2011
DOI:10.1039/C1NR10247H
In this paper, a stable and highly efficient plasmonic photocatalyst, Ag@AgCl, with cube-like morphology, has been successfully prepared via a simple hydrothermal method. Using methylene dichloride as chlorine source in the synthesis can efficiently control the morphology of Ag@AgCl, due to the low release rate of chloride ions. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra were used to characterize the obtained product. The photocatalytic activity of the obtained product was evaluated by the photodegradation of methyl orange (MO) under visible light irradiation, and it was found, interestingly, that Ag@AgCl exhibits high visible light photocatalytic activity and good stability.
Co-reporter:Ping Wang, Yueming Zhai, Dejun Wang and Shaojun Dong
Nanoscale 2011 vol. 3(Issue 4) pp:1640-1645
Publication Date(Web):01 Feb 2011
DOI:10.1039/C0NR00714E
The construction of reduced graphene oxide or graphene oxide with semiconductor has gained more and more attention due to its unexpected optoelectronic and electronic properties. The synthesis of reduced graphene oxide (RGO) or graphene oxide-semiconductor nanocomposite with well-dispersed decorated particles is still a challenge now. Herein, we demonstrate a facile method for the synthesis of graphene oxide-amorphous TiO2 and reduced graphene oxide-anatase TiO2 nanocomposites with well-dispersed particles. The as-synthesized samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis absorption spectroscopy, Fourier transform infrared spectrometry, and thermogravimetric analysis. The photovoltaic properties of RGO-anatase TiO2 were also compared with that of similar sized anatase TiO2 by transient photovoltage technique, and it was interesting to find that the combination of reduced graphene oxide with anatase TiO2 will significantly increase the photovoltaic response and retard the recombination of electron-hole pairs in the excited anatase TiO2.
Co-reporter:Chengzhou Zhu, Youxing Fang, Dan Wen and Shaojun Dong
Journal of Materials Chemistry A 2011 vol. 21(Issue 42) pp:16911-16917
Publication Date(Web):15 Jul 2011
DOI:10.1039/C1JM11612F
A one-step approach to synthesize functional two-dimensional graphene/SnO2 composite nanosheets (GSCN) is reported. It should be noted that SnCl2 is not only a reducing agent for graphene oxide (GO), but also a precursor of SnO2. On the other hand, polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) was introduced simultaneously in the preparation, to endow it with an ideal self-assembly building block. Through electrostatic interaction, a general method has been developed for the preparation of ternary GSCN/nanoparticles (GSCN/NPs) hybrid structures with high-density noble metal NPs. Prominent examples including Au, Pt and Au@Pt hybrid NPs could be loaded on the surface of GSCN. Furthermore, we employed high-density Au@Pt NPs supported on GSCN as the electrochemical material for nonenzymatic glucose detection, which exhibited good electrocatalytic activity.
Co-reporter:Shaojun Guo and Shaojun Dong
Journal of Materials Chemistry A 2011 vol. 21(Issue 42) pp:16704-16716
Publication Date(Web):12 Jul 2011
DOI:10.1039/C1JM11382H
Metal nanomaterials (MNMs) have received considerable interest from different scientific communities due to their size, shape, composition and architecture-dependent chemical and physical properties. MNMs-based self-assembly techniques are often essential for creating new multi-dimensional assembly architectures, which are very important for revealing new or enhanced properties and application potentials. This feature article will focus on recent advances in MNMs-based self-assembly and their potential application in electrochemical sensor and surface enhanced Raman spectroscopy (SERS). First, new significant developments in different self-assembly strategies for constructing two-dimensional (2D) and three-dimensional (3D) MNMs-based arrays or superstructures will be summarized. Then, diversified assembling approaches to different types of hybrid or multifunctional nanomaterials containing MNMs will be outlined. The review next introduces some exciting new pushes for the use of nanoarchitectures produced through self-assembly techniques for applications in electrochemical sensors and SERS. Finally, we conclude with a look at the future challenges and prospects of the development of MNMs-based self-assembly.
Co-reporter:Liu Deng, Zhixue Zhou, Jing Li, Tao Li and Shaojun Dong
Chemical Communications 2011 vol. 47(Issue 39) pp:11065-11067
Publication Date(Web):06 Sep 2011
DOI:10.1039/C1CC14012D
Using the Hg2+-mediated T–T formation to strengthen the DNA duplexes and influence the configuration of fluorescent Ag NCs-forming sequences, a turn-on fluorescence detection method for Hg2+ has been established.
Co-reporter:Yueming Zhai, Lihua Jin, Ping Wang and Shaojun Dong
Chemical Communications 2011 vol. 47(Issue 29) pp:8268-8270
Publication Date(Web):22 Jun 2011
DOI:10.1039/C1CC13149D
We demonstrate for the first time that bifunctional Au–Fe3O4 dumbbell nanoparticles can be used for sensitive and selective turn-on fluorescent detection of cyanide based on the inner filter effect, and a “magnetic concentration–washing process” is proposed to effectively reduce the interference of dye pollution.
Co-reporter:Li Wang, Chengzhou Zhu, Lei Han, Lihua Jin, Ming Zhou and Shaojun Dong
Chemical Communications 2011 vol. 47(Issue 27) pp:7794-7796
Publication Date(Web):02 Jun 2011
DOI:10.1039/C1CC11373A
Label-free, regenerative and sensitive surface plasmon resonance (SPR) and electrochemical aptasensors based on graphene for the detection of α-thrombin have been reported, which propose a new, simple way for protein recognition with high sensitivity and selectivity.
Co-reporter:Yan Du, Chaogui Chen, Ming Zhou, Shaojun Dong, and Erkang Wang
Analytical Chemistry 2011 Volume 83(Issue 5) pp:1523
Publication Date(Web):February 3, 2011
DOI:10.1021/ac101988n
Aptamers are artificial oligonucleotides that have been widely employed to design biosensors (i.e., aptasensors). In this work, we report a microfluidic electrochemical aptamer-based sensor (MECAS) by constructing Au−Ag dual-metal array three-electrode on-chip for multiplex detection of small molecules. In combination with the microfluidic channels covering on the glass chip, different targets are transported to the Au electrodes integrated on different positions of the chip. These electrodes are premodified by different kinds of aptamers, respectively, to fabricate different sensing interfaces which can selectively capture the corresponding target. It is an address-dependent sensing platform; thus, with the use of only one electrochemical probe, multitargets can be recognized and detected according to the readout on a corresponding aptamer-modified electrode. In the sensing strategy, the electrochemical probe, [Ru(NH3)6]3+ (RuHex), which can quantitatively bind to surface-confined DNA via electrostatic interaction, was used to produce chronocoulometric signal; Au nanoparticles (AuNPs) were used to improve the sensitivity of the sensor by amplifying the detection signals. Moreover, the sensing interface fabrication, sample incubation, and electrochemical detection were all performed in microfluidic channels. By using this detection chip, we achieved the multianalysis of two model small molecules, ATP, and cocaine, in mixed samples within 40 min. The detection limit of ATP was 3 × 10−10 M, whereas the detection limit of cocaine was 7 × 10−8 M. This Au−Ag dual metal electrochemical chip detector integrated MECAS was simple, sensitive, and selective. Also it is similar to a dosimeter which accumulates signal upon exposure. It held promising potential for designing electrochemical devices with high throughput, high automation, and high integration in multianalysis.
Co-reporter:Dan Wen, Liu Deng, Shaojun Guo, and Shaojun Dong
Analytical Chemistry 2011 Volume 83(Issue 10) pp:3968
Publication Date(Web):April 15, 2011
DOI:10.1021/ac2001884
A self-powered electrochemical sensor has been facilely designed for sensitive detection of Hg2+ based on the inhibition of biocatalysis process of enzymatic biofuel cell (BFC) for the first time. The as-prepared one-compartment BFC, which was consisted of alcohol dehydrogenase supported on single-walled carbon nanohorns-based mediator system as the anode and bilirubin oxidase as the cathodic biocatalyst, generated an open circuit potential (Voc) of 636 mV and a maximum power density of 137 μW cm–2. It was interestingly found that the presence of Hg2+ would affect the performance of the constructed BFC (e.g., Voc). Taking advantage of the inhibitive effect of Hg2+, a novel self-powered Hg2+ sensor has been developed, which showed a linear range of 1–500 nM (R2 = 0.999) with a detection limit of 1 nM at room temperature. In addition, this BFC-type sensor exhibited good selectivity for Hg2+ against other common environmental metal ions, and the feasibility of the method for Hg2+ detection in actual water samples (i.e., tap, ground, and lake water) was demonstrated with satisfactory results.
Co-reporter:Zhixue Zhou, Yan Du, and Shaojun Dong
Analytical Chemistry 2011 Volume 83(Issue 13) pp:5122
Publication Date(Web):May 25, 2011
DOI:10.1021/ac200120g
Double-strand DNA (dsDNA) can act as an efficient template for the formation of copper nanoparticles (Cu NPs) at low concentration of CuSO4, and the formed Cu NPs have excellent fluorescence, whereas a single-strand DNA (ssDNA) template does not support Cu NPs’ formation. This property of dsDNA-Cu NPs makes it suitable for DNA sensing. However, exploration of dsDNA-Cu NPs applied in biological analysis is still at an early stage. In this regard, we report herein for the first time a sensitive, cost-effective, and simple aptamer sensor (aptasensor) using dsDNA-Cu NPs as fluorescent probe. The design consists of a dsDNA with reporter DNA (here, aptamer) as template for the formation of Cu NPs, and the formed dsDNA-Cu NPs show high fluorescence. Using adenosine triphosphate (ATP) as a model analyte, the introduction of ATP triggers the structure switching of reporter DNA to form aptamer-ATP complex, causing the destruction of the double helix and thus no formation of the Cu NPs, resulting in low fluorescence. The preferable linear range (0.05–500 μM), sensitivity (LOD 28 nM), and simplicity for the detection of ATP indicate that dsDNA-Cu NPs may have great prospects in the field of biological analysis. We also use this novel fluorescent probe to determine ATP in 1% human serum and human adenocarcinoma HeLa cells. The dsDNA-Cu NPs probes provide recovery of 104–108% in 1% human serum and a prominent fluorescent signal is obtained in cellular ATP assay, revealing the practicality of using dsDNA–Cu NPs for the determination of ATP in real samples. Besides, this design is simply based on nucleic acid hybridization, so it can be generally applied to other aptamers for label-free detection of a broad range of analytes. Successful detection of cocaine with detection limit of 0.1 μM demonstrates its potential to be a general method.
Co-reporter:Shaojun Guo, Yan Du, Xuan Yang, Shaojun Dong, and Erkang Wang
Analytical Chemistry 2011 Volume 83(Issue 20) pp:8035
Publication Date(Web):September 12, 2011
DOI:10.1021/ac2019552
Taking advantage of strand-displacement DNA polymerization and parallel-motif DNA triplex system as dual amplifications, a new electrochemical label-free integrated aptasensor based on silver microspheres (SMSs) as a separation element and graphene-mesoporous silica–gold nanoparticle (NP) hybrids (GSGHs) as an enhanced element of the sensing platform was first reported. In this sensing design (schematic representation of the sensing procedure for adenosine triphosphate detection, Scheme 1 in manuscript text), which contains an enhanced three-step magnification process, SMSs with “clean” surface were first used to separate the undesirable aptamer and aptamer–adenosine triphosphate (ATP) complex attached on SMSs surface after aptamer–ATP interaction, which lead to the detachment of blocker DNA into the solution phase. Then, under the assistance of blocker DNA, an amplified method based on the inherent signal-transduction mechanism of the hairpin probe and strand-displacement property of DNA polymerase was introduced. The obtained duplex DNA was used to hybridize with an acceptor DNA assembled on electrode to form triplex DNA, which could bring a more obvious detection signal compared with the duplex DNA without the amplification. The electrochemical signal came from the GSGH-based enhanced sensing interface containing positively charged ferrocene-appended poly(ethyleneimine) (Fc-PEI). Using the above multiple effects, we could achieve the sensitive analysis of a model small molecule–ATP (an important “molecular currency” of intracellular energy transfer) in a wide detection range from 0.05 nM to 56.5 nM with the detection limit of 0.023 nM.
Co-reporter:Yaqing Liu, Erkang Wang, Shaojun Dong
Electrochemistry Communications 2011 Volume 13(Issue 9) pp:906-908
Publication Date(Web):September 2011
DOI:10.1016/j.elecom.2011.03.030
Co-reporter:Daming Yong, Ling Liu, Dengbin Yu, Shaojun Dong
Analytica Chimica Acta 2011 Volume 701(Issue 2) pp:164-168
Publication Date(Web):9 September 2011
DOI:10.1016/j.aca.2011.06.044
In this paper, a mediated method by using ferricyanide under non-deaerated condition for biotoxicity measurement was proposed. Ultramicroelectrode array (UMEA) was employed for effectively amplify the electrochemical signal from the total limiting currents to distinguish a little change in toxicity. Five species of microorganisms including two bacilli (Escherichia coli and Enterobacter cloacae), two pseudomonas (Pseudomonas fluorescens and Pseucomonas putida) and one fungus (Trichosporon cutaneum) were employed. 3,5-dichlorophenol (DCP) was taken as the reference toxicant. The IC50 values we obtained were similar with the values obtained using in the deaerated method. E. coli was used as model test microorganism. The final concentration of ferricyanide is 45 mM, E. coli OD600 8 and 1 h incubation were taken in optimum conditions in this study. Four heavy metal ions (Cr6+, Hg2+, Cd2+ and Bi3+) were examined under the optimum conditions. Comparison with the results reported previously has confirmed that this method provided a simple and rapid alternative to toxicity screening of chemicals, especially advantageous for in situ monitoring of water system.Graphical abstractHighlights• We had explored a novel NDA-FM-TOX method for measurement of toxicity. • This method did not require both of air supply and deaerated equipment for rapid measuring of real polluted wastewater. • It has been developed successfully for the detection of various toxic substances.
Co-reporter:Yan Du, Bingling Li, Shaojun Guo, Zhixue Zhou, Ming Zhou, Erkang Wang and Shaojun Dong
Analyst 2011 vol. 136(Issue 3) pp:493-497
Publication Date(Web):16 Nov 2010
DOI:10.1039/C0AN00557F
The appearance of the aptamer provides good recognition elements for small molecules, especially for drugs. In this work, by combining the advantages of magnetic nanoparticles (MNPs) with colorimetric drug detection using hemin-G-quadruplex complex as the sensing element, we report a simple and sensitive DNAzyme-based colorimetric sensor for cocaine detection in a 3,3,5,5-tetramethylbenzidine sulfate (TMB)–H2O2 reaction system. The whole experimental processes are simplified. Cocaine aptamer fragments, SH–C2, are covalently labeled onto the amine-functionalized MNPs. When the target cocaine and another cocaine aptamer fragments (C1) grafted with G-riched strand AG4 (i.e. C1–AG4) are present simultaneously, the C2 layer on MNPs hybridizes partly with C1–AG4 to bind the cocaine. The C1–AG4 can be combinded with hemin to form DNAzyme which can effectively catalyze the H2O2-mediated oxidation of TMB, giving rise to a change in solution color. Importantly, using MNPs as the separation and amplification elements could effectively reduce the background signal and the interference from the real samples. A linear response from 0.1 μM to 20 μM is obtained for cocaine and a detection limit of 50 nM is achieved, which provides high sensitivity and selectivity to detect cocaine.
Co-reporter:Yujing Guo, Jing Li, Shaojun Dong
Sensors and Actuators B: Chemical 2011 160(1) pp: 295-300
Publication Date(Web):
DOI:10.1016/j.snb.2011.07.050
Co-reporter:Daming Yong, Chang Liu, Dengbin Yu, Shaojun Dong
Talanta 2011 Volume 84(Issue 1) pp:7-12
Publication Date(Web):15 March 2011
DOI:10.1016/j.talanta.2010.11.012
We reported a rapid toxicity assay method using electrochemical biosensor for pesticides, Escherichia coli (E. coli) was taken as a model microorganism for test. In this method, we adopted ferricyanide instead of natural electron acceptor O2, and then microbial oxidation was substantially accelerated. Toxicity assays measured the effect of toxic materials on the metabolic activity of microorganisms. The current signal of ferrocyanide produced from the metabolism was proven to be directly related to the toxicity, which could be amplified by ultramicroelectrode array (UMEA). The ratio of the electrochemical signals, recorded in the presence and absence of toxin, provided an index of inhibition. Accordingly, a direct toxicity assessment (DTA) based on chronoamperometry was proposed to detect the effect of toxic chemicals on microorganisms. 3,5-Dichlorophenol (DCP) was taken as the reference toxicant, its IC50 was estimated to be 8.0 mg/L. Three pesticides were examined using this method. IC50 values of 6.5 mg/L for Ametryn, 22 mg/L for Fenamiphos and 5.7 mg/L for Endosulfan were determined and in line with EC50 values reported in the literature. Atomic force microscopy (AFM) was also used for morphology characterization of E. coli induced by three pesticides. These results confirmed the present electrochemical method used is reliable. In addition, the electrochemical method is a sensitive, rapid and inexpensive way for toxicity assays of pesticides.
Co-reporter:Yujing Guo, Shaojun Guo, Jing Li, Erkang Wang, Shaojun Dong
Talanta 2011 Volume 84(Issue 1) pp:60-64
Publication Date(Web):15 March 2011
DOI:10.1016/j.talanta.2010.12.007
In this paper, cyclodextrin–graphene hybrid nanosheets (CD–GNs) for the first time have been used as an enhanced material for ultrasensitive detection of carbendazim by electrochemistry method. The peak currents of carbendazim on the GNs modified glassy carbon electrode (GNs/GCE) and the CD–GNs/GCE are increased by 11.7 and 82.0 folds compared to the bare GCE, respectively. This indicates the nanocomposite film not only shows the excellent electrical properties of GNs but also exhibits high supramolecular recognition capability of CDs. At the CD–GNs/GCE, the peak currents increase linearly with the concentration of carbendazim in the range of 5 nM–0.45 μM. The detection limit of carbendazim reached to 2 nM on the basis of the signal-to-noise characteristics (S/N = 3) and the recoveries were between 98.9% and 104.5%. The developed electrochemical sensor exhibited good stability and reproducibility for the detection of carbendazim. And the CD–GNs based electrochemical sensor was also successfully demonstrated for the detection of carbendazim in water sample with satisfactory results. Furthermore, this simple sensing platform can in principle be extended to the detection of other benzimidazole fungicide which can form host–guest complexes with cyclodextrin.
Co-reporter:Ping Wang;Lei Han;Chengzhou Zhu;Yueming Zhai
Nano Research 2011 Volume 4( Issue 11) pp:1153-1162
Publication Date(Web):2011 November
DOI:10.1007/s12274-011-0165-2
Co-reporter:Changyu Liu, Chao Ma, Dengbin Yu, Jianbo Jia, Ling Liu, Bailin Zhang, Shaojun Dong
Biosensors and Bioelectronics 2011 Volume 26(Issue 5) pp:2074-2079
Publication Date(Web):15 January 2011
DOI:10.1016/j.bios.2010.09.004
To improve the practicability of rapid biochemical oxygen demand (BOD) method, we proposed a stable BOD sensor based on immobilizing multi-species BODseed for wastewater monitoring in the flow system. The activation time of the biofilm was greatly shortened for the biofilm prepared by BODseed in the organic–inorganic hybrid material. Some influence factors such as temperature, pH, and concentration of phosphate buffer solution (PBS) were investigated in detail in which high tolerance to environment was validated for the BOD sensor permitted a wide pH and PBS concentration ranges. The minimum detectable BOD was around 0.5 mg/l BOD under the optimized 1.0 mg/ml BODseed immobilized concentration. The as-prepared BOD sensor exhibited excellent stability and reproducibility for different samples. Furthermore, the as-prepared BOD biosensor displayed a notable advantage in indiscriminate biodegradation to different organic compounds and their mixture, similar to the character of conventional BOD5 results. The results of the BOD sensor method are well agreed with those obtained from conventional BOD5 method for wastewater samples. The proposed rapid BOD sensor method should be promising in practical application of wastewater monitoring.
Co-reporter:Shaojun Guo, Dan Wen, Yueming Zhai, Shaojun Dong, Erkang Wang
Biosensors and Bioelectronics 2011 Volume 26(Issue 8) pp:3475-3481
Publication Date(Web):15 April 2011
DOI:10.1016/j.bios.2011.01.028
Trinitrotoluene, usually known as TNT, is a kind of chemical explosive with hazardous and toxic effects on the environment and human health. Ever-increasing needs for a secure society and green environment essentially require the detection of TNT with rapidity, high sensitivity and low cost. In this article, ionic liquid–graphene hybrid nanosheets (IL–GNs) have been used as an enhanced material for rapidly electrochemical detection of trinitrotoluene (TNT). IL–GNs were characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray photo-electron spectroscopy, electrochemical impedance spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy, which confirmed that IL has been effectively functionalized on the surface of GNs. Significantly, IL–GNs modified glassy carbon electrode (GCE) showed 6.2 and 51.4-folds higher current signals for TNT reduction than IL–CNTs/GCE and bare GCE, respectively. Adsorptive stripping voltammetry (ASV) for the detection of TNT on IL–GNs exhibited a good linear range from 0.03 to 1.5 ppm with a detection limit of 4 ppb on the basis of the signal-to-noise characteristics (S/N = 3). Moreover, IL–GNs/GCE exhibited good stability and reproducibility for the detection of TNT. And, IL–GNs based electrochemical detection platform was also successfully demonstrated for the detection of TNT in ground water, tap water, and lake water with satisfactory results.
Co-reporter:Yujing Guo, Liu Deng, Jing Li, Shaojun Guo, Erkang Wang, and Shaojun Dong
ACS Nano 2011 Volume 5(Issue 2) pp:1282
Publication Date(Web):January 10, 2011
DOI:10.1021/nn1029586
This paper demonstrated for the first time a simple wet-chemical strategy for synthesizing hemin−graphene hybrid nanosheets (H-GNs) through the π−π interactions. Significantly, this new material possesses the advantages of both hemin and graphene and exhibits three interesting properties. First, H-GNs have intrinsic peroxidase-like activity, which can catalyze the reaction of peroxidase substrate, due to the existence of hemin on the graphene surface. Second, their dispersion follow the 2D Schulze−Hardy rule, that is to say, the coagulation of H-GNs in electrolyte solution results from the interplay between van der Waals attraction and electric double-layer repulsion. Third, H-GNs exhibit the ability to differentiate ss- and ds-DNA in optimum electrolyte concentration, owing to the different affinities of ss- and ds-DNA to the H-GNs. On the basis of these unique properties of the as-prepared H-GNs, we have developed a label-free colorimetric detection system for single-nucleotide polymorphisms (SNPs) in disease-associated DNA. To our knowledge, this is the first report concerning on SNPs detection using functionalized graphene nanosheets. Owing to its easy operation and high specificity, it was expected that the proposed procedure might hold great promise in the pathogenic diagnosis and genetic diseases.Keywords (keywords): artificial enzyme mimetic; graphene nanosheet; hemin; single-nucleotide polymorphism
Co-reporter:Lihua Jin, Youxing Fang, Dan Wen, Li Wang, Erkang Wang, and Shaojun Dong
ACS Nano 2011 Volume 5(Issue 6) pp:5249
Publication Date(Web):May 24, 2011
DOI:10.1021/nn201455a
In this study, we fabricated a novel hybrid film system, in which reversible electroswitching quantum dot (QD) luminescence was realized in aqueous solution for the first time. On the basis of an electrochromic material, poly(methylene blue) (PMB), QD luminescence could be switched effectively in a narrow potential range of −0.4 to 0 V via the corresponding luminescence quenching effect. The luminescence switching operation was reversible and reproducible, and no noticeable changes in both “on” and “off” luminescence intensities were observed in 20 cycles. This simple system not only effectively overcame the harsh operation environment that generally existed in previous reports but also provided an easy method for the design and fabrication of other novel QD electroswitchable hybrid components.Keywords: electrochromic; electroswitch; luminescence; poly(methylene blue); quantum dots
Co-reporter:Yueming Zhai, Lei Han, Ping Wang, Gaiping Li, Wen Ren, Ling Liu, Erkang Wang, and Shaojun Dong
ACS Nano 2011 Volume 5(Issue 11) pp:8562
Publication Date(Web):September 28, 2011
DOI:10.1021/nn201875k
Magnetic materials and noble metal-based multifunctional hybrids have attracted much attention recently due to their unique properties and potential applications in a variety of fields. However, substantial challenges remain to directly obtain water-soluble hybrids with well-defined structures and to directly combine magnetic nanoparticles with nonspherical noble metals. We describe here for the first time a simple solvothermal method to synthesize a series of novel water-soluble nanohybrids composed of shape-tuned Ag cores and a Fe3O4 shell. We found that small Fe3O4 grains can be well-distributed directly on the surface on the Ag seeds. Such hybrids have both plasmonic and significant superparamagnetic properties, enabling magnetic separation. The plasmon resonance frequency of Ag nanostructures can be fine-tuned through the interactions between the two components. In addition, the decorated Fe3O4 nanoparticles stabilized the Ag nanostructures when exposed to air and natural light for a long time. Furthermore, an interesting structural transformation is observed in the one-dimensional Ag–Fe3O4 nanowires under high-energy electron beam. The Ag core can diffuse through the porous iron oxide shell, break away, and result in the formation of Ag nanocluster-decorated iron oxide tubes. Finally, the hybrids acted as a chemical template for the synthesis of Fe3O4/Au-AgCl double-layer nanotubes that display obvious near-infrared absorption. Importantly, the double-layer nanotubes exhibited enhanced photocatalytic inactivation of bacteria at very low concentrations under natural sunlight.Keywords: electron-beam irradiation; iron oxide; nanohybrids; phototoxicity; silver; superparamagnetic materials
Co-reporter:Tao Li, Libing Zhang, Jun Ai, Shaojun Dong, and Erkang Wang
ACS Nano 2011 Volume 5(Issue 8) pp:6334
Publication Date(Web):July 6, 2011
DOI:10.1021/nn201407h
A novel kind of versatile logic device has been constructed utilizing ion-tuned DNA/Ag fluorescent nanoclusters, with K+ and H+ as two inputs. A well-chosen hairpin DNA with a poly-C loop serves as the template for synthesizing two species of Ag nanoclusters. Several G-tracts and C-tracts on its two terminals enable the hairpin DNA to convert into the G-quadruplex and/or i-motif structures upon input of K+ and H+. Such a structural change remarkably influences the spectral behaviors of Ag nanoclusters. In particular, different species of Ag nanoclusters have distinct fluorescence responses to the input of K+ and H+. These unique features of DNA/Ag nanoclusters enable multiple logic operations via multichannel fluorescence output, indicating the versatility as a molecular logic device. By altering the specific sequence of the hairpin DNA, more logic gates can be constructed utilizing Ag nanoclusters.Keywords: DNA structural change; DNA/Ag nanoclusters; fluorescence spectrum; logic gates
Co-reporter:Lihua Jin, Li Shang, Shaojun Guo, Youxing Fang, Dan Wen, Li Wang, Jianyuan Yin, Shaojun Dong
Biosensors and Bioelectronics 2011 Volume 26(Issue 5) pp:1965-1969
Publication Date(Web):15 January 2011
DOI:10.1016/j.bios.2010.08.019
In this work, biomolecule-stabilized Au nanoclusters were demonstrated as a novel fluorescence probe for sensitive and selective detection of glucose. The fluorescence of Au nanoclusters was found to be quenched effectively by the enzymatically generated hydrogen peroxide (H2O2). By virtue of the specific response, the present assay allowed for the selective determination of glucose in the range of 1.0 × 10−5 M to 0.5 × 10−3 M with a detection limit of 5.0 × 10−6 M. The absorption spectroscopy, X-ray photoelectron spectroscopy (XPS) and fluorescence decay studies were then performed to discuss the quenching mechanism. In addition, we demonstrated the application of the present approach in real serum samples, which suggested its great potential for diagnostic purposes.
Co-reporter:Zhixue Zhou, Yan Du, Shaojun Dong
Biosensors and Bioelectronics 2011 Volume 28(Issue 1) pp:33-37
Publication Date(Web):15 October 2011
DOI:10.1016/j.bios.2011.06.028
As promising substitutes for organic dyes and quantum dots, few-atom fluorescent silver nanoclusters (Ag NCs) have recently gained much attention in a wide range from cellular imaging to chemical/biological detection applications owing to their ultrasmall size (<2 nm), excellent photostability, good biocompatibility and water solubility. Herein, we design an aptamer, guanine-rich (G-rich) DNA and Ag NCs nanocomplex to investigate its ability for the detection of small molecules. The design contains two DNA strands which are both chimeric conjugates of the DNA aptamer sequence fragment and G-rich sequence fragment. Using cocaine as a model molecule, the two DNA strands are in free state if there is no cocaine present, and the formed Ag NCs through the reduction of Ag+ by NaBH4 show weak fluorescence emission. In the presence of cocaine, however, the two aptamer fragments bind cocaine, which in turn puts the two G-rich sequence fragments in proximity and the fluorescent intensity of DNA–Ag NCs enhances greatly. As a result, DNA–Ag NCs are demonstrated as a novel, cost-effective and turn-on fluorescent probe for the analysis of cocaine, with a detection limit of 0.1 μM. Besides, successful detection of adenosine triphosphate (ATP) with detection limit of 0.2 μM demonstrates its potential to be a general method.Highlights► A novel fluorescent aptamer sensor for small molecules was developed using DNA–Ag nanoclusters as probes. ► DNA–Ag nanoclusters were demonstrated as a cost-effective and turn-on fluorescent probe for the analysis of cocaine. ► The proposed design can be generally applied to other aptamers for turn-on detection of a broad range of analytes.
Co-reporter:Chang Liu, Daming Yong, Dengbin Yu, Shaojun Dong
Talanta 2011 Volume 84(Issue 3) pp:766-770
Publication Date(Web):15 May 2011
DOI:10.1016/j.talanta.2011.02.006
A cost-effective whole cell biosensor based on electrochemical technique to detect toxicities of phenol and nitrophenols has been developed. This method relied on the inhibition effect for respiratory chain activity of microorganism by toxicant, which was measured by chronoamperometry using mediator (ferricyanide). The current signals produced by suspended microorganisms and reoxidation of ferrocyanide were transformed to inhibiting efficiency directly, and 50% inhibiting concentration (IC50) was chosen as the quantitative standard of toxicity. The test microorganisms used here consist of three bacilli (Escherichia coli, Enterobacter cloacae and Alcaligenes faecalis), two pseudomonas (Pseudomonas fluorescens and Pseucomonas putida) and one fungus (Trichosporon cutaneum). 3,5-Dichlorophenol (DCP) was taken as the reference toxicant. The results showed that the microorganisms which belong to the same bacterial family had similar trends of inhibitions on respiratory activity and similar IC50 values. By comparing the IC50 values, P. fluorescens was the most sensitive one to DCP toxicity, its IC50 was estimated to be 4.2 mg/L. pH 7.0 and together with the standard glucose–glutamic acid (GGA) as an exogenous material were taken for optimum conditions in this study. Here, P. fluorescens as model test microorganism was employed to assess toxicities of phenol and nitrophenols under the optimum conditions. IC50 values of 291.4 mg/L for phenol, 64.1 mg/L for 2-NP, 71.4 mg/L for 3-NP and 14.0 mg/L for 4-NP were determined at 60 min, respectively. Comparison with the results of published data has confirmed that this cell biosensor is a sensitive and rapid alternative to toxicity screening of chemicals.
Co-reporter:Yan Du, Shaojun Guo, Shaojun Dong, Erkang Wang
Biomaterials 2011 32(33) pp: 8584-8592
Publication Date(Web):
DOI:10.1016/j.biomaterials.2011.07.091
Co-reporter:Chengzhou Zhu;Shaojun Guo;Youxing Fang;Lei Han;Erkang Wang
Nano Research 2011 Volume 4( Issue 7) pp:648-657
Publication Date(Web):2011 July
DOI:10.1007/s12274-011-0120-2
Co-reporter:Ling Liu, Liu Deng, Daming Yong, Shaojun Dong
Talanta 2011 Volume 84(Issue 3) pp:895-899
Publication Date(Web):15 May 2011
DOI:10.1016/j.talanta.2011.02.025
In this article, we developed a native biofilm (NBF) bioreactor used for biochemical oxygen demand mediated method (BODMed). There were two innovations differed from previous BODMed assay. Firstly, the immobilization of microorganisms was adopted in BODMed. Secondly, the NBF was introduced for BOD measurement. The NBF bioreactor has been characterized by optical microscopy. A culture condition of NBF with 24 h, 35 °C and pH 7 was optimized. Furthermore, a measuring condition with 35 °C, pH 7 and 55 mM ferricyanide in 1 h incubation were optimized. Based on the optimized condition, the real wastewater samples from local sewage treatment plant had been measured. Performances of the NBFs proposed at different culture conditions were recorded for 110 d, and the results indicated that long-term storage stability was obtained. With the proposed method, an uncontaminated native microbial source solution can be obtained from a wastewater treatment plant. In this way, we can ensure that the microbial species of all in the NBF are same as that in the target to be measured.
Co-reporter:Ming Zhou ; Yan Du ; Chaogui Chen ; Bingling Li ; Dan Wen ; Shaojun Dong ;Erkang Wang
Journal of the American Chemical Society 2010 Volume 132(Issue 7) pp:2172-2174
Publication Date(Web):February 1, 2010
DOI:10.1021/ja910634e
This communication demonstrates for the first time the controlled power release of biofuel cells (BFCs) by aptamer logic systems processed according to the Boolean logic operations “programmed” into the biocomputing systems. On the basis of the built-in Boolean NAND logic, the fabricated aptamer-based BFCs logically controlled by biochemical signals enabled us to construct self-powered and intelligent logic aptasensors that can determine whether the two specific targets are both present in a sample.
Co-reporter:Liu Deng, Shaojun Guo, Zuojia Liu, Ming Zhou, Dan Li, Ling Liu, Gaiping Li, Erkang Wang and Shaojun Dong
Chemical Communications 2010 vol. 46(Issue 38) pp:7172-7174
Publication Date(Web):18 Aug 2010
DOI:10.1039/C0CC01371D
A significant increase (ca. 22-fold) in the electricity generation due to a Shewanella oneidensis MR-1 biofilm was observed in the presence of Fe3O4/Au nanocomposites.
Co-reporter:Chengzhou Zhu, Shaojun Guo, Ping Wang, Li Xing, Youxing Fang, Yueming Zhai and Shaojun Dong
Chemical Communications 2010 vol. 46(Issue 38) pp:7148-7150
Publication Date(Web):23 Jul 2010
DOI:10.1039/C0CC01459A
A novel and facile process is reported for water-phase synthesis of high-quality graphene/TiO2 composite nanosheets (GTCN) on a large scale using TiCl3 as both a reducing agent and a precursor.
Co-reporter:Shaojun Guo, Shaojun Dong and Erkang Wang
Chemical Communications 2010 vol. 46(Issue 11) pp:1869-1871
Publication Date(Web):13 Jan 2010
DOI:10.1039/B922148D
We for the first time report a facile, wet-chemical strategy for the high-yield (∼100%) synthesis of ultralong Pt-on-Pd bimetallic nanowires (NWs) with the cores being Pd NWs and the shells being made of dendritic Pt, which exhibit high surface area and enhanced electrocatalytic activity towards methanol oxidation reaction.
Co-reporter:Yueming Zhai, Junfeng Zhai and Shaojun Dong
Chemical Communications 2010 vol. 46(Issue 9) pp:1500-1502
Publication Date(Web):23 Dec 2009
DOI:10.1039/B923466G
Chain-like and ring-like CoPt hollow nanoparticles were facilely obtained via a one-pot synthesis process, and we found that temperature played an important role in the assembly morphology.
Co-reporter:Yan Du, Chaogui Chen, Jianyuan Yin, Bingling Li, Ming Zhou, Shaojun Dong and Erkang Wang
Analytical Chemistry 2010 Volume 82(Issue 4) pp:1556
Publication Date(Web):January 22, 2010
DOI:10.1021/ac902566u
Aptamers, which are artificial oligonucleotides selected in vitro, have been employed to design novel biosensors (i.e., aptasensors). In this work, we first constructed a label-free electrochemical aptasensor introducing a probe immobilization technique by the use of a layer-by-layer (LBL) self-assembled multilayer with ferrocene−appended poly(ethyleneimine) (Fc−PEI) on an indium tin oxide (ITO) array electrode for detection of cocaine. The Fc−PEI and gold nanoparticles (AuNPs) were LBL assembled on the electrode surface via electrostatic interaction. Then, cocaine aptamer fragments, SH-C2, were covalently labeled onto the outermost AuNP layer. When the target cocaine and cocaine aptamer C1 were present simultaneously, the SH-C2 layer hybridized partly with C1 to bind the cocaine, which led to a decreased differential pulse voltammetry (DPV) signal of Fc−PEI. This DPV signal change could be used to sensitively detect cocaine with the lowest detectable concentration down to 0.1 μM and the detection range up to 38.8 μM, which falls in the the expected range for medical use of detecting drug abuse involving cocaine. Meanwhile, the sensor was specific to cocaine in complex biologic fluids such as human plasma, human saliva, etc. The sensing strategy had general applicability, and the detection of thrombin could also be realized, displayed a low detection limit, and exhibited worthiness to other analytes. The aptasensor based on the array electrode held promising potential for integration of the sensing ability in multianalysis for simultaneous detection.
Co-reporter:Liu Deng, Chaogui Chen, Ming Zhou, Shaojun Guo, Erkang Wang and Shaojun Dong
Analytical Chemistry 2010 Volume 82(Issue 10) pp:4283
Publication Date(Web):April 19, 2010
DOI:10.1021/ac100274s
In this work we developed a fully integrated biofuel cell on a microchip, which consisted of glucose dehydrogenase supported (carbon nanotubes/thionine/gold nanoparticles)8 multilayer as the anode, and the (carbon nanotubes/polylysine/laccase)15 multilayer as the cathode. The as-obtained biofuel cell produced open circuit potential 620 mV and power density 302 μW cm−2, showing great potential as a small power resource of portable electronics. Most importantly, for the first time we demonstrated the feasibility of developing a self-powered biosensor based on the inhibitive effect on microchip enzyme biofuel cell. With cyanide employed as the model analyte, this method showed a linear range of 3.0 × 10−7 to 5.0 × 10−4 M and a detection limit with 1.0 × 10−7 M under the optimal conditions. The detection limit was lower than the acceptable cyanide concentration in drinking water (1.9 × 10−6 M) according to the World Health Organization (WHO). This self-powered sensor was successfully used to detect the cyanide concentration in a real sample, cassava, which is the main carbohydrate resource in South America and Africa. This presented biosensor combined with a resistor and a multimeter demonstrated the general applicability as a fast and simple detection method in the determination of endogenous biological cyanide.
Co-reporter:Tao Li, Erkang Wang, and Shaojun Dong
Analytical Chemistry 2010 Volume 82(Issue 18) pp:7576
Publication Date(Web):August 20, 2010
DOI:10.1021/ac1019446
Here we demonstrate an anionic porphyrin, protoporphyrin IX (PPIX), as a parallel G-quadruplex-specific fluorescent probe for monitoring DNA structural changes and utilize it to develop a DNA-based K+ sensor. The interactions of PPIX with different DNA structures in K+ or Na+ solution are investigated by using circular dichroism, fluorescence, and UV−vis spectroscopy. The observations reveal that PPIX has an ∼100-fold selectivity for parallel G-quadruplexes against duplexes and antiparallel G-quadruplexes. Meanwhile, the fluorescence intensity of PPIX increases by over 10-fold upon binding to parallel G-quadruplexes. On the basis of the selectivity and fluorescence property of PPIX, we introduce a facile, label-free approach to monitoring DNA structural changes via fluorescence signal readout that is tuned by PPIX binding and release. To illustrate it, we utilize PPIX and a G-rich DNA PS2.M to construct a fluorescent K+ sensor based on an antiparallel-to-parallel conformation transition of the G-quadruplex. PS2.M adopts an antiparallel quadruplex structure in Na+ solution, whereas it gradually converts into a parallel G-quadruplex upon addition of increasing K+. This conformational change is indicated by a sharp increase in the fluorescence intensity of PPIX, owing to the good ability of PPIX to discriminate parallel G-quadruplexes from antiparallel ones. Even in the presence of 100 mM Na+, such a “turn-on” fluorescent sensor can respond to low concentrations of K+, with a limit of detection (0.5 mM) for K+ analysis. In addition, this sensor exhibits a high selectivity for K+ over other common metal ions, which ensures its practical applications to real samples. These results reveal that PPIX is promising for use as a specific DNA structural probe in sensing applications.
Co-reporter:Ming Zhou, Chaogui Chen, Yan Du, Bingling Li, Dan Wen, Shaojun Dong and Erkang Wang
Lab on a Chip 2010 vol. 10(Issue 21) pp:2932-2936
Publication Date(Web):21 Sep 2010
DOI:10.1039/C0LC00009D
The development of microfluidic devices has been spurred by the desire to produce low-cost point-of-care diagnostics and environmental monitoring devices. By combining the adaptive behavior of microfluidic biofuel cells (micro-BFCs) self-regulating the power release with aptamer IMP logic, we constructed a novel IMP-Reset gate-based reusable and self-powered on-chip aptasensor, which can be used to logically determine the presence of one specific target in the absence of another target in complex physiological samples (such as human serum) in a single test.
Co-reporter:Yujing Guo, Shaojun Guo, Youxing Fang, Shaojun Dong
Electrochimica Acta 2010 Volume 55(Issue 12) pp:3927-3931
Publication Date(Web):30 April 2010
DOI:10.1016/j.electacta.2010.02.024
In this work, a highly sensitive electrochemical sensor for the determination of tryptophan (Trp) was fabricate by electrodeposition of gold nanoparticles (AuNPs) onto carbon nanotube (CNT) films pre-cast on a glassy carbon electrode (GCE), forming an AuNP–CNT composite-modified GCE (AuNP–CNT/GCE). Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used for the surface analysis of the electrode. The results indicate that the hybrid nanomaterials induced a substantial decrease in the overpotential of the Trp oxidation reaction and exhibited a remarkable synergistic effect on the electrocatalytic activity toward the oxidation of Trp. In phosphate buffer solution (pH 7.4), the modified electrode showed excellent analytical performance for the amperometric determination of Trp. The peak currents possess a linear relationship with the concentration of Trp in the range of 30 nM to 2.5 μM, and the detection limit is 10 nM (S/N = 3). In addition, the modified electrode was used to determine Trp concentration in pharmaceutical samples with satisfactory results.
Co-reporter:Xiao-Long XU, Jian-Bo JIA, Xiu-Rong YANG, Shao-Jun DONG
Chinese Journal of Analytical Chemistry 2010 Volume 38(Issue 12) pp:1687-1691
Publication Date(Web):December 2010
DOI:10.1016/S1872-2040(09)60079-7
In this article, we reported a one-step facile route to fabricate Pd-modified porous Au electrode. During fabrication, the surface of a pristine Au microdisk array electrode underwent oxidation, reduction, and Pd deposition while applying three potentials (high, low, or lower, respectively). We optimized the preparation conditions, such as buffer pH and oxidation time. On a preparation condition that 90 s oxidation in phosphate buffer saline solution with pH 7, we obtained a 42-fold larger electroactive surface area at porous electrode than that of bare electrode. Pd nanoparticles (PdNPs) were modified on the porous electrode subsequently, and the loading of Pd could be easily tuned by varying the deposition time. The as-prepared Pd-modified electrode was used for electrocatalytic reduction of dissolved oxygen, and this showed a sensitivity of 0.1 mA L cm−2 mg−1. The one-step facile route of fabrication is convenient, environmentally benign, and a promising method to prepare PdNPs-modified porous Au electrode.
Co-reporter:Dan Wen, Shaojun Guo, Yizhe Wang and Shaojun Dong
Langmuir 2010 Volume 26(Issue 13) pp:11401-11406
Publication Date(Web):April 6, 2010
DOI:10.1021/la100869r
A novel metal/semiconductor hybrid nanostructure with enhanced catalytic functions has been prepared by a simple self-assembly approach. This new bifunctional nanocatalyst consists of evenly dispersed Au/Pt hybrid nanoparticles (Au/Pt NPs) assembled on NH2 group functionalized anatase TiO2 colloid spheres with nanoporous surface (f-TiO2). The resulting bimetallic nanoparticles/TiO2 (noted as f-TiO2−Au/Pt NPs) hybrid nanostructure is characterized by various methods and expected as a promising catalyst in electrochemical and photoelectrochemical applications because of its satisfactory or even enhanced catalytic properties from both TiO2 and Au/Pt NPs. Compared with the f-TiO2, the electrochemical results indicate that the as-prepared f-TiO2−Au/Pt NPs exhibited more prominent electrocatalytic reduction toward hydrogen peroxide at low potential, which was then used as a sensitive sensor with a detection limit of 75 nM. Most importantly, the present hybrid material has the better photocatalytic property, as demonstrated by the photoelectrochemical catalysis of glucose.
Co-reporter:Lihua Jin, Li Shang, Junfeng Zhai, Jing Li and Shaojun Dong
The Journal of Physical Chemistry C 2010 Volume 114(Issue 2) pp:803-807
Publication Date(Web):December 21, 2009
DOI:10.1021/jp908574z
The change of the photoluminescence (PL) property of CdTe quantum dot (QD) assembled multilayers along with applied potential has been investigated in aqueous solution. By using the in situ fluorescence spectroelectrochemistry technique, we examined the PL property of QDs upon applying potentials under different atmosphere media, in air and in nitrogen. It was found that when the sample was under nitrogen or exposed to air, the luminescence of QDs bear quenching by adding positive potentials. On the contrary, while applying negative potentials, the luminescence of QD was weakened only in the air condition. It seemed that the luminescence of CdTe QDs was hardly affected by the potentials under nitrogen. On the basis of the phenomena, electrochemistry and X-ray photoelectron spectroscopy (XPS) measurements were then performed to explain the possible origins of PL changes. The results clearly indicated that the variation of surface structure of QDs affected the PL property of CdTe QDs significantly.
Co-reporter:Xiaolong Xu, Jianbo Jia, Xiurong Yang and Shaojun Dong
Langmuir 2010 Volume 26(Issue 10) pp:7627-7631
Publication Date(Web):January 25, 2010
DOI:10.1021/la904245q
A templateless, surfactantless, simple electrochemical route to prepare dendritic gold nanostructure is reported. The morphology, composition, and structure of as-prepared dendritic gold nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The whole nanostructure was constructed by pristine metallic gold. The formation mechanism related to experimental conditions was discussed. The synthesis promises indium tin oxide (ITO) electrode can be easily modified with the dendritic pristine gold nanostructure. The as-prepared modified ITO electrode has excellent catalytic activity to oxygen reduction in neutral KCl solution.
Co-reporter:Ping Wang;Tengfei Jiang;Chengzhou Zhu;Yueming Zhai;Dejun Wang
Nano Research 2010 Volume 3( Issue 11) pp:794-799
Publication Date(Web):2010 November
DOI:10.1007/s12274-010-0046-0
The synthesis of graphene-semiconductor nanocomposites has attracted increasing attention due to their interesting optoelectronic properties. However the synthesis of such nanocomposites, with decorated particles well dispersed on graphene, is still a great challenge. This work reports a facile, one-step, solvothermal method for the synthesis of graphene-CdS and graphene-ZnS quantum dot nanocomposites directly from graphene oxide, with CdS and ZnS very well dispersed on the graphene nanosheets. Photoluminescence measurements showed that the integration of CdS and ZnS with graphene significantly decreases their photoluminescence. Transient photovoltage studies revealed that the graphene-CdS nanocomposite exhibits a very unexpected strong positive photovoltaic response, while separate samples of graphene and CdS quantum dots (QDs) of a similar size do not show any photovoltaic response.
Co-reporter:Ling Liu, Changyu Liu, Li Shang, Dan Li, Daming Yong, Li Qi, Shaojun Dong
Talanta 2010 Volume 83(Issue 1) pp:31-35
Publication Date(Web):15 November 2010
DOI:10.1016/j.talanta.2010.08.034
Co-reporter:Li Wang, Fuan Wang, Li Shang, Chengzhou Zhu, Wen Ren, Shaojun Dong
Talanta 2010 Volume 82(Issue 1) pp:113-117
Publication Date(Web):30 June 2010
DOI:10.1016/j.talanta.2010.04.009
Co-reporter:Ling Liu, Li Shang, Chang Liu, Changyu Liu, Bailin Zhang, Shaojun Dong
Talanta 2010 Volume 81(4–5) pp:1170-1175
Publication Date(Web):15 June 2010
DOI:10.1016/j.talanta.2010.01.062
Monitoring biochemical oxygen demand (BOD) by mediator method (BODMed) has been developed for recent years and deaerated condition was generally adopted to avoid the effect of oxygen, but the deaerated condition was unfavorable in practical applications. Herein, we first proposed another way to explore non-deaerated BODMed (called NDA-BODMed) method utilizing ferricyanide, which was reduced by Escherichia coli upon catalyzing organic substrate to produce ferrocyanide. We attempted to explain the feasibility of NDA-BODMed by the two aspects. Firstly, the obtained biodegradation efficiencies of the bacteria under the deaerated and non-deaerated conditions were similar, and the concentration of O2 (0.25 mM at 8 mg/L O2) is 1–2 order of magnitude lower than that of mediator commonly used (55 mM ferricyanide), so the effect of O2 to measurements could be neglected. Secondly, the relationship between the artificial and the natural electron acceptor was investigated, and it was found that the oxygen consumption in the NDA-BODMed measurement was mainly contributed to endogenous values. Furthermore, the performance of present NDA-BODMed was reported, and this method was optimized for measuring the low-concentration samples, synthetic wastewater and real polluted wastewater. The NDA-BODMed provides a simple and efficient way in rapid BOD determinations, especially advantageous for in situ monitoring of water system.
Co-reporter:Dan Wen, Shaojun Guo, Shaojun Dong, Erkang Wang
Biosensors and Bioelectronics 2010 Volume 26(Issue 3) pp:1056-1061
Publication Date(Web):15 November 2010
DOI:10.1016/j.bios.2010.08.054
Nanomaterial modified electrode is useful for catalytic, analytical and biotechnological applications. Herein, a simple and sensitive method for the electrocatalytic detection of ascorbic acid (AA) using ultrathin Pd nanowire (NW) modified glassy carbon electrode is presented. Electrochemical data reveal that Pd NWs can effectively enhance the electron transfer between AA and electrode, and thus reduce the overpotential of AA oxidation. Particularly, the current–time curve shows that the catalytic oxidation current is linearly dependent on AA concentration in the range of 25 μM–0.9 mM with a correlation coefficient 0.9998, and a detection limit of 0.2 μM (S/N = 3) is obtained with an excellent reproducibility. What is more, the present Pd NWs-based electrochemical sensing platform can successfully be used as enhanced element for the detection of AA in the practical samples such as human serum and vitamin C beverage with satisfactory results.
Co-reporter:Li Wang, Tao Li, Yan Du, Chaogui Chen, Bingling Li, Ming Zhou, Shaojun Dong
Biosensors and Bioelectronics 2010 Volume 25(Issue 12) pp:2622-2626
Publication Date(Web):15 August 2010
DOI:10.1016/j.bios.2010.04.027
We reported a sensitive surface plasmon resonance (SPR) sensor for the detection of Hg2+ in aqueous solution by using a thymine (T)-rich, mercury-specific oligonucleotide (MSO) probe and gold nanoparticles (Au NPs)-based signal amplification. The MSO probe was first immobilized on gold film through formation of Au–S bond between DNA and gold film. In the presence of Hg2+, the MSO probe captured free Hg2+ in aqueous media via the Hg2+-mediated coordination of T–Hg2+–T base pairs. This direct immobilization strategy led to a detection limit of 0.3 μM of Hg2+. In order to improve the sensitivity, part complementary DNA (PCS)-modified Au NPs labels were employed to amplify SPR signals. We demonstrated that this Au NPs-based sensing strategy resulted in a detection limit down to 5 nM of Hg2+, brings about an amplification factor of two orders of magnitude. This Au NPs-based Hg2+ sensor also exhibited excellent selectivity over a spectrum of interference metal ions. Taking advantage of the high amplifying characteristic of Au NPs and the specificity of MSO to Hg2+ recognition, we developed here a SPR sensor for specific Hg2+ detection with high sensitivity.
Co-reporter:Liu Deng, Shaojun Guo, Ming Zhou, Ling Liu, Chang Liu, Shaojun Dong
Biosensors and Bioelectronics 2010 Volume 25(Issue 10) pp:2189-2193
Publication Date(Web):15 June 2010
DOI:10.1016/j.bios.2010.02.005
We present here a facile and efficient route to prepare silk derived carbon mat modified with Au@Pt urchilike nanoparticles (Au@Pt NPs) and develop an Escherichia coli (E. coli)-based electrochemical sensor using this material. Silk is a natural protein fiber, and it is abundant with kinds of functionalities which are important in the development of the derived material. The S-derived carbon fiber mat have amino, pyridine and carbonyl functional groups, these natural existent functionalities allow the Au@Pt NPs to self-assemble on the carbon fiber surface and provide a biocompatible microenvironment for bacteria. The Au@Pt NPs modified S-derived carbon fiber is sensitive to detect the E. coli activities with a low detection limit, where glucose is used as a prelimiltary substrate to evaluate them. The performance of Au@Pt/carbon fiber mat based biosensor is much better than that of commercial carbon paper based biosensor. The high sensitivity of this biosensor stems from the unique electrocatalytic properties of Au@Pt urchilike NPs and quinone groups presented in S-derived carbon fiber. This biosensor is also tested for detection of organophosphate pesticides, fenamiphos. The relative inhibition of E. coli activity is linear with −log[fenamiphos] at the concentration range from 0.5 mg/L to 36.6 mg/L with lowest observable effect concentration (LOEC) of 0.09 mg/L. The Au@Pt NPs modified S-derived carbon fiber mat possesses high conductivity, biocompatibility and high electrocatalytic activity and be can used as advanced electrode materials for microbial biosensor improvement. The microbial biosensor based on this material shows potential applications in environmental monitoring.
Co-reporter:Li Shang, Lihua Jin, Shaojun Guo, Junfeng Zhai and Shaojun Dong
Langmuir 2010 Volume 26(Issue 9) pp:6713-6719
Publication Date(Web):December 17, 2009
DOI:10.1021/la9040612
A new synthesis strategy has been developed for the preparation of bimetallic gold−silver (Au−Ag) alloy nanoparticles by the virtue of polyelectrolyte multilayer (PEM) nanoreactors. By controlling the assembly conditions, gold and silver ions can be effectively loaded onto the PEM composed of polyethylenimine (PEI) and poly(acrylic acid) (PAA) simultaneously. Upon further thermal treatment, Au−Ag alloy nanoparticles with sizes of ca. 3.8 nm formed in the PEM, which were characterized in detail by UV−vis absorption spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) analysis. Appearance of a single plasmon band in the visible region and lack of apparent core−shell structures in the TEM images confirm the formation of homogeneous Au−Ag alloy nanoparticles. In addition, the surface plasmon absorption band of the Au−Ag alloy nanoparticles shows linear blue-shift with increasing Ag content, which also supported the formation of alloy nanoparticles. Several key parameters of the present strategy have been investigated, which showed that pH of both the assembly solution and gold salt solution and the choice of polymers for constructing PEM, as well as the reduction approach, all played an important role in successfully synthesizing bimetallic Au−Ag nanoparticles. The formation mechanism of alloy nanoparticles has also been discussed based on the spectral evolution during the thermal reduction.
Co-reporter:Liu Deng, Li Shang, Dan Wen, Junfeng Zhai, Shaojun Dong
Biosensors and Bioelectronics 2010 Volume 26(Issue 1) pp:70-73
Publication Date(Web):15 September 2010
DOI:10.1016/j.bios.2010.05.007
In this study, we reported on the construction of a stable single-chamber ethanol/O2 biofuel cell harvesting energy from the ethanol and alcoholic beverage. We prepared a composite film which consisted of partially sulfonated (3-mercaptopropyl)-trimethoxysilane sol–gel (PSSG) and chitosan (CHI). The combination of ion-exchange capacity sol–gel and biopolymer chitosan not only provided the attached sites for mediator MDB and AuNPs to facilitate the electron transfer along the substrate reaction, but also gave the suitable microenvironment to retain the enzyme activity in long term. The ethanol bioanode was constructed with the film coimmobilized dehydrogenase (ADH), Meldola's blue (MDB) and gold nanoparticles (AuNPs). The MDB/AuNPs/PSSG-CHI-ADH composite modified electrode showed prominent electrocatalytic activity towards the oxidation of ethanol. The oxygen biocathode consisted of laccase and AuNPs immobilized on the PSSG–CHI composite membrane. The AuNPs/PSSG–CHI-laccase modified electrode catalyzed four-electron reduction of O2 to water, without any mediator. The assembled single-chamber biofuel cell exhibited good stability and power output towards ethanol. The open-circuit voltage of this biofuel cell was 860 mV. The maximum power density of the biofuel cell was 1.56 mW cm−2 at 550 mV. Most interestingly, this biofuel cell showed the similar performance when the alcoholic beverage acted as the fuel. When this biofuel cell ran with wine as the fuel, the maximum power output density was 3.21 mA cm−2 and the maximum power density was 1.78 mW cm−2 at 680 mV of the cell voltage. Our system exhibited stable and high power output in the multi-component substrate condition. This cell has great potential for the development and practical application of bioethanol fuel cell.
Co-reporter:Dan Wen, Liu Deng, Ming Zhou, Shaojun Guo, Li Shang, Guobao Xu, Shaojun Dong
Biosensors and Bioelectronics 2010 Volume 25(Issue 6) pp:1544-1547
Publication Date(Web):15 February 2010
DOI:10.1016/j.bios.2009.11.007
Single-walled carbon nanohorns (SWNHs), a new type of carbon nanomaterials, possess excellent catalytic properties, high-purity, and low toxicities, which make them suitable for bioelectrochemical application. Here a biofuel cell anode has been developed by using SWNHs as the support for redox mediator and biocatalyst for the first time. Cyclic voltammetric results show SWNHs promotes the electropolymerization of methylene blue (MB) and the resulted nanocomposite (poly MB–SWNHs) exhibits prominent catalytic ability to the oxidation of nicotinamide adenine dinucleotide. Glucose dehydrogenase was then immobilized on the poly MB–SWNHs modified electrode for the oxidation of glucose. Employing Pt nanoparticles supported on functionalized TiO2 colloidal spheres with nanoporous surface as cathode catalyst, the as-assembled glucose/O2 biofuel cell operate at the physiological condition with good performance.
Co-reporter:Yan Du, Chaogui Chen, Bingling Li, Ming Zhou, Erkang Wang, Shaojun Dong
Biosensors and Bioelectronics 2010 Volume 25(Issue 8) pp:1902-1907
Publication Date(Web):15 April 2010
DOI:10.1016/j.bios.2010.01.003
Herein, we report two simple label-free electrochemical aptasensors for protein detection using layer-by-layer (LBL) self-assembled multilayers with ferrocene-appended poly(ethyleneimine) (Fc-PEI), carbon nanotubes (CNTs) and aptamer. In one sensing strategy, the Fc-PEI, CNTs and DNA aptamer are LBL assembled on the electrode surface via electrostatic interaction. In the presence of target, the aptamer on the outermost layer of the LBL self-assembled multilayer would catch the target on the electrode interface, which makes a barrier for electrons and inhibits the electro-transfer, resulting in the decreased DPV signals of Fc-PEI. Using this strategy, a wide detection range (0.3–165 ng ml−1) for model target thrombin is obtained, with a low detection limit of 0.14 ng ml−1. In the similar sensing strategy for detection of lysozyme, a wide detection range (0.2 ng ml−1 to 1.66 μg ml−1) and a low detection limit (0.17 ng ml−1) are obtained. These results prove that the LBL sensing strategies developed possess sensitivity, selectivity, stability and generality.
Co-reporter:Liu Deng, Ming Zhou, Chang Liu, Ling Liu, Changyun Liu, Shaojun Dong
Talanta 2010 Volume 81(1–2) pp:444-448
Publication Date(Web):15 April 2010
DOI:10.1016/j.talanta.2009.12.022
In this paper, we synthesized a unique cathode catalyst Co/Fe/N/CNTs with high performance oxygen reduction. Through the π-stacking force, the cobalt porphyrins (CoTMPP) and iron phthanlocyanine (FePc) were deposited to the carbon nanotubes (CNTs) sidewall. The CoTMPP/FePc functionalized CNTs were used as the precursor to prepare the Co/Fe/N/CNTs based oxygen reduction nanocatalyst through high-temperature pyrolysis. The as-prepared catalyst exhibited higher electrocatalytic activity for the reduction of dioxygen than that of the Co/Fe/N/graphite and commercial Pt/C. The high electrocatalytic activity and good stability for dioxygen reduction made the Co/Fe/N/CNT as a potential candidate for the efficient cathode material in microbial fuel cells (MFCs). The maximum power of the MFC using the Co/Fe/N/CNT as cathode catalyst is 751 mW m−2, which was 1.5 times larger than the MFC with the commercial Pt/C catalyst under the same condition. Such an approach is useful for the improvement of the cathode performance and to provide the basis for the development of the efficient MFC cathodes.
Co-reporter:Chengzhou Zhu, Shaojun Guo, Youxing Fang and Shaojun Dong
ACS Nano 2010 Volume 4(Issue 4) pp:2429
Publication Date(Web):April 1, 2010
DOI:10.1021/nn1002387
In this paper, we developed a green and facile approach to the synthesis of chemically converted graphene nanosheets (GNS) based on reducing sugars, such as glucose, fructose and sucrose using exfoliated graphite oxide (GO) as precursor. The obtained GNS is characterized with atomic force microscopy, UV−visible absorption spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and so on. The merit of this method is that both the reducing agents themselves and the oxidized products are environmentally friendly. It should be noted that, besides the mild reduction capability to GO, the oxidized products of reducing sugars could also play an important role as a capping reagent in stabilizing as-prepared GNS simultaneously, which exhibited good stability in water. This approach can open up the new possibility for preparing GNS in large-scale production alternatively. Moreover, it is found that GNS-based materials could be of great value for applications in various fields, such as good electrocatalytic activity toward catecholamines (dopamine, epinephrine, and norepinephrine).Keywords: catecholamines; electrocatalysis; graphene nanosheets; reducing sugar
Co-reporter:Yujing Guo, Shaojun Guo, Jiangtao Ren, Yueming Zhai, Shaojun Dong and Erkang Wang
ACS Nano 2010 Volume 4(Issue 7) pp:4001
Publication Date(Web):June 28, 2010
DOI:10.1021/nn100939n
Cyclodextrins (CDs) are oligosaccharides composed of six, seven, or eight glucose units (α-, β-, or γ-CD, respectively), which are toroidal in shape with a hydrophobic inner cavity and a hydrophilic exterior. These interesting characteristics can enable them to bind selectively various organic, inorganic and biological guest molecules into their cavities to form stable host−guest inclusion complexes or nanostructured supramolecular assemblies in their hydrophobic cavity. On the other hand graphene nanosheet (GN), a rising-star material, holds great promise for potential applications in many technological fields due to its high surface areas, low cost, and high conductivity. If GNs are modified with CDs, it is possible to obtain new materials simultaneously possessing unique properties of GNs and cyclodextrins through combining their individual obvious advantages. In this article, we demonstrate for the first time a simple wet-chemical strategy for the preparation of CD−graphene organic−inorganic hybrid nanosheets (CD−GNs), which exhibited high solubility and stability in polar solvent. The obtained CD−GNs were characterized by UV−vis spectroscopy, static contact angle measurement, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy, which confirmed that CD had been effectively functionalized on the surface of GNs. Furthermore, the formation mechanism of CD−GNs was also discussed. Interestingly, GNs here could load a number of CD molecules, which was very important for greatly enhancing the supramolecular function of CDs. Electrochemical results obviously reveal that CD−graphene organic−inorganic hybrid nanosheets could exhibit very high supramolecular recognition and enrichment capability and show much higher electrochemical response toward eight probe molecules (biomolecules and drugs) than unmodified GNs and carbon nanotubes, which is probably caused by the synergetic effects from GNs (high conductivity and high surface area) and CD molecules (host−guest recognition and enrichment).Keywords: cyclodextrin; electrocatalysis; electrochemical device; graphene; supramolecular
Co-reporter:Shaojun Guo, Dan Wen, Yueming Zhai, Shaojun Dong and Erkang Wang
ACS Nano 2010 Volume 4(Issue 7) pp:3959
Publication Date(Web):June 22, 2010
DOI:10.1021/nn100852h
The development of nanoscience and nanotechnology has inspired scientists to continuously explore new electrode materials for constructing an enhanced electrochemical platform for sensing. In this article, we proposed a new Pt nanoparticle (NP) ensemble-on-graphene hybrid nanosheet (PNEGHNs), a new electrode material, which was rapidly prepared through a one-step microwave-assisted heating procedure. The advantages of PNEGHNs modified glassy carbon electrode (GCE) (PNEGHNs/GCE) are illustrated from comparison with the graphenes (GNs) modified GCE for electrocatalytic and sensing applications. The electrocatalytic activities toward several organic and inorganic electroactive compounds at the PNEGHNs/GCE were investigated, all of which show a remarkable increase in electrochemical performance relative to GNs/GCE. Hydrogen peroxide (H2O2) and trinitrotoluene (TNT) were used as two representative analytes to demonstrate the sensing performance of PNEGHNs. It is found that PNEGHNs modified GCE shows a wide linear range and low detection limit for H2O2 and TNT detection. Therefore, PNEGHNs may be an attractive robust and advanced hybrid electrode material with great promise for electrochemical sensors and biosensors design.Keywords: electrocatalysis; graphene; hybrid nanomateirals; Pt nanoparticle; sensor
Co-reporter:Chengzhou Zhu, Shaojun Guo, Yueming Zhai and Shaojun Dong
Langmuir 2010 Volume 26(Issue 10) pp:7614-7618
Publication Date(Web):January 14, 2010
DOI:10.1021/la904201j
In this report, we succeed in constructing a hybrid three-dimensional (3D) nanocomposite film by alternatively assembling the graphene nanosheets modified by ionic liquid (IL) and Pt nanoparticles (Pt NPs). In this strategy, an imidazolium salt-based ionic liquid (IS-IL)-functionalized graphene was synthesized by covalently binding 1-(3-aminopropyl)-3-methylimidazolium bromide onto graphene nanosheets. The introduction of IS-IL on the surface of graphene nanosheets can obtain dispersed graphene nanosheets with positive charge. Also, the desired functionalization of graphene can form the building blocks for constructing hybrid 3D nanocomposite film. Then, the positively charged IS-IL-functionalized graphene nanosheets are strong enough to drive the formation of the 3D nanomaterials with negatively charged citrate-stabilized Pt NPs through electrostatic interaction. As far as we know, the reports on the layer-by-layer (LBL) self-assembly of G-IS-IL and nanoparticle multilayer films are few at the moment. UV−visible−near-infrared (UV−vis−NIR) absorption spectroscopy, atomic force microscopy (AFM) and cyclic voltammetry (CV) were used to characterize the uniform growth of the multilayer film. The newly prepared 3D nanomaterials containing G-IS-IL and Pt NPs show high electrocatalytic activity toward oxygen reduction. Furthermore, the electrocatalytic activity of the films could be further tailored by simply choosing different cycles in the LBL process. This demonstration offers a new route to assemble graphene/nanoparticle multilayer films and opens up the possibility of building more complex multicomponent nanostructures, which are believed to be useful for electrochemical nanodevices.
Co-reporter:Ming Zhou;Xiliang Zheng;Jin Wang
Chemistry - A European Journal 2010 Volume 16( Issue 26) pp:7719-7724
Publication Date(Web):
DOI:10.1002/chem.201000619
Co-reporter:Tao Li ; Erkang Wang
Journal of the American Chemical Society 2009 Volume 131(Issue 42) pp:15082-15083
Publication Date(Web):October 6, 2009
DOI:10.1021/ja9051075
A cation-driven allosteric G-quadruplex DNAzyme (PW17) was utilized to devise a conceptually new class of DNA logic gate based on cation-tuned ligand binding and release. K+ favors the binding of hemin to parallel-stranded PW17, thereby promoting the DNAzyme activity, whereas Pb2+ induces PW17 to undergo a parallel-to-antiparallel conformation transition and thus drives hemin to release from the G-quadruplex, deactivating the DNAzyme. Such a K+−Pb2+ switched G-quadruplex, in fact, functions as a two-input INHIBIT logic gate. With the introduction of another input EDTA, this G-quadruplex can be further utilized to construct a reversibly operated IMPLICATION gate.
Co-reporter:Yueming Zhai, Junfeng Zhai, Ming Zhou and Shaojun Dong
Journal of Materials Chemistry A 2009 vol. 19(Issue 38) pp:7030-7035
Publication Date(Web):14 Aug 2009
DOI:10.1039/B912767D
In this paper, we have reported a facile method for the synthesis of ordered magnetic core–manganese oxide shell nanostructures. The process included two steps. First, manganese ferrite nanoparticles were obtained through a solvothermal method. Then, the manganese ferrite nanoparticles were mixed directly with KMnO4 solution without any additional modified procedures of the magnetic cores. It has been found that Mn element in the core can react with KMnO4 to form manganese oxide which acts as a seed for the in-situgrowth of manganese oxide shells. This is significant for the controllable fabrication of symmetrical ordered manganese oxide shell structures. The shell thickness can be easily controlled through the reaction time. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction and energy-dispersive X-ray spectroscopy have been employed to characterize the products at different reaction time. The magnetic materials can be used as absorbents in wastewater treatment and exhibit a strong capability to remove organic pollutants. Furthermore, the materials are superparamagnetic and exhibit relative high saturation magnetization at room temperature, which makes the separation procedure more convenient in wastewater treatment.
Co-reporter:Tao Li, Bingling Li, Erkang Wang and Shaojun Dong
Chemical Communications 2009 (Issue 24) pp:3551-3553
Publication Date(Web):07 May 2009
DOI:10.1039/B903993G
Hg2+ is able to inhibit the peroxidase-like DNAzyme function of a T-containing G-quadruplex DNAviaHg2+-mediated T–T base pairs, which enables the visual detection of Hg2+ in the TMB–H2O2 reaction system with high selectivity and sensitivity.
Co-reporter:Li Shang, Lihua Jin and Shaojun Dong
Chemical Communications 2009 (Issue 21) pp:3077-3079
Publication Date(Web):14 Apr 2009
DOI:10.1039/B902216C
We report a simple fluorescent method for sensitive cyanide detection based on the dissolution of Rhodamine B-adsorbed gold nanoparticles by cyanide.
Co-reporter:Tao Li, Erkang Wang and Shaojun Dong
Chemical Communications 2009 (Issue 5) pp:580-582
Publication Date(Web):05 Dec 2008
DOI:10.1039/B815814B
Two G-quadruplexDNAs are able to form peroxidase-like DNAzymes selectively promoted by K+, which provides a label-free approach to colorimetric detection of K+ with the highest sensitivity ever reported.
Co-reporter:Li Shang and Shaojun Dong
Analytical Chemistry 2009 Volume 81(Issue 4) pp:1465
Publication Date(Web):January 13, 2009
DOI:10.1021/ac802281x
We have demonstrated the design of a new type fluorescent assay based on the inner filter effect (IFE) of metal nanoparticles (NPs), which is conceptually different from the previously reported metal NPs-based fluorescent assays. With a high extinction coefficient and tunable plasmon absorption feature, metal NPs are expected to be capable of functioning as a powerful absorber to tune the emission of the fluorophore in the IFE-based fluorescent assays. In this work, we presented two proof-of-concept examples based on the IFE of Au NPs by choosing MDMO-PPV as a model fluorophore, whose fluorescence could be tuned by the absorbance of Au NPs with a much higher sensitivity than the corresponding absorbance approach. While the first assay worked in a turn-on mode upon the etching of Au NPs by the analyte, CN−, the second one functioned in a turn-off mode upon the catalytic growth of Au NPs by the analyte, H2O2. As a result, the present IFE-based approach can detect cyanide ranging from 1.0 × 10−6 to 6.0 × 10−4 M with a detection limit of 6.0 × 10−7 M and H2O2 ranging from 1.5 × 10−7 to 2.2 × 10−5 M with a detection limit of 8.5 × 10−8 M, respectively. Notably, the present IFE-based approach allows the design of fluorescent assays in a more simple, time-saving, and economical approach when compared with conventional metal NPs-based fluorescent assays, since no modification step of the fluorophore was needed any more.
Co-reporter:Bingling Li, Chuanjiang Qin, Tao Li, Lixiang Wang and Shaojun Dong
Analytical Chemistry 2009 Volume 81(Issue 9) pp:3544
Publication Date(Web):April 3, 2009
DOI:10.1021/ac900110a
Here, a fluorescent switch is constructed combining hemin, hemin aptamer, and a newly synthesized anionic conjugated polymer (ACP), poly(9,9-bis(6′-phosphatehexyl) fluorenealt-1,4-phenylene) sodium salt (PFHPNa/PFP). In the “off-state”, the fluorescence of PFP is sensitively quenched by hemin, with a high Ksv value of ∼107. While in the “on-state”, the formation of the aptamer/hemin complex recovers the fluorescence intensity. The fluorescent switch is sensitive and selective to hemin. To testify the universality and practicality of the fluorescent switch, a series of label-free DNA-related sensing platforms are developed, containing three DNA sensing strategies and one ATP recognition strategy. The fluorescent switch developed is simple, sensitive, and universal, which extends applications of the anionic conjugated polymers.
Co-reporter:Ming Zhou, Yueming Zhai and Shaojun Dong
Analytical Chemistry 2009 Volume 81(Issue 14) pp:5603
Publication Date(Web):June 12, 2009
DOI:10.1021/ac900136z
In this paper, the characterization and application of a chemically reduced graphene oxide modified glassy carbon (CR-GO/GC) electrode, a novel electrode system, for the preparation of electrochemical sensing and biosensing platform are proposed. Different kinds of important inorganic and organic electroactive compounds (i.e., probe molecule (potassium ferricyanide), free bases of DNA (guanine (G), adenine (A), thymine (T), and cytosine (C)), oxidase/dehydrogenase-related molecules (hydrogen peroxide (H2O2)/β-nicotinamide adenine dinucleotide (NADH)), neurotransmitters (dopamine (DA)), and other biological molecules (ascorbic acid (AA), uric acid (UA), and acetaminophen (APAP)) were employed to study their electrochemical responses at the CR-GO/GC electrode, which shows more favorable electron transfer kinetics than graphite modified glassy carbon (graphite/GC) and glassy carbon (GC) electrodes. The greatly enhanced electrochemical reactivity of the four free bases of DNA at the CR-GO/GC electrode compared with that at graphite/GC and GC electrodes makes the CR-GO/GC electrode a better choice for the electrochemical biosensing of four DNA bases in both the single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) at physiological pH without a prehydrolysis step. This allows us to detect a single-nucleotide polymorphism (SNP) site for short oligomers with a particular sequence at the CR-GO/GC electrode without any hybridization or labeling processes in this work, suggesting the potential applications of CR-GO in the label-free electrochemical detection of DNA hybridization or DNA damage for further research. Based on the greatly enhanced electrochemical reactivity of H2O2 and NADH at the CR-GO/GC electrode, CR-GO/GC electrode-based bioelectrodes (in connection with glucose oxidase (GOD) and alcohol dehydrogenase (ADH)) show a better analytical performance for the detection of glucose and ethanol compared with graphite/GC- or GC-based bioelectrodes. By comparing the electrochemical performance of CR-GO with that of the conventional graphite and GC, we reveal that CR-GO with the nature of a single sheet showing favorable electrochemical activity should be a kind of more robust and advanced carbon electrode material which may hold great promise for electrochemical sensors and biosensors design.
Co-reporter:Bingling Li, Yan Du, Shaojun Dong
Analytica Chimica Acta 2009 Volume 644(1–2) pp:78-82
Publication Date(Web):30 June 2009
DOI:10.1016/j.aca.2009.04.022
In this work, we reported both unlabeled and labeled sensing strategies for Ag(I) ions detection by using the DNA based gold nanoparticles (AuNPs) colorimetric method. In the unlabeled strategy, C-base riched single strand DNA (C-ssDNA) enwinded onto AuNPs to form AuNPs/C-ssDNA complex. In the labeled method, sulfhydryl group modified C-ssDNA (HS-C-ssDNA) was covalently labeled on AuNPs to produce AuNPs-S-C-ssDNA complex. In both strategies, C-ssDNA or HS-C-ssDNA could enhance the AuNPs stability against the salt-induced aggregation. However, the presence of Ag(I) ions in the obtained AuNPs/C-ssDNA or AuNPs-S-C-ssDNA complex would decrease such stability to display purple even blue colors due to the formation of Ag(I) ions mediated C-Ag(I)-C base pairs. Through this phenomenon, Ag(I) ions could be detected qualitatively and quantitatively using both unlabeled and labeled sensing strategies. Compared with the labeled method, the unlabeled strategy avoided the label and separation steps in common sensors, which may thus save both the time and cost for the detection. Nevertheless, the labeled strategy provided more sensitive, stable and controllable sensing results compared with the unlabeled method. By the labeled strategy, 12 nM Ag(I) ions could be observed directly by naked eyes, and the lowest detectable concentration of 0.59 nM was gotten under by the UV–vis spectra measurement, which was one of the most sensitive results among DNA based AuNPs colorimetric sensors for metal ions.
Co-reporter:Chang Liu, Ting Sun, Xiaolong Xu, Shaojun Dong
Analytica Chimica Acta 2009 Volume 641(1–2) pp:59-63
Publication Date(Web):8 May 2009
DOI:10.1016/j.aca.2009.03.027
Electrochemical measurement of respiratory chain activity is a rapid and reliable screening for the toxicity on microorganisms. Here, we investigated in-vitro effects of toxin on Escherichia coli (E. coli) that was taken as a model microorganism incubated with ferricyanide. The current signal of ferrocyanide effectively amplified by ultramicroelectrode array (UMEA), which was proven to be directly related to the toxicity. Accordingly, a direct toxicity assessment (DTA) based on chronoamperometry was proposed to detect the effect of toxic chemicals on microorganisms. The electrochemical responses to 3,5-dichlorophenol (DCP) under the incubation times revealed that the toxicity reached a stable level at 60 min, and its 50% inhibiting concentration (IC50) was estimated to be 8.0 mg L−1. At 60 min incubation, the IC50 values for KCN and As2O3 in water samples were 4.9 mg L−1 and 18.3 mg L−1, respectively. But the heavy metal ions, such as Cu2+, Pb2+ and Ni2+, showed no obvious toxicity on E. coli. With the exception of Hg2+, it showed 40.0 mg L−1 IC50 value when E. coli was exposed to its solution for 60 min. The lower sensitivity of DTA for the heavy metal ions could be attributed to the toxicological endpoint and the experimental conditions used. All results suggest that the DTA is a sensitive, rapid and inexpensive alternative to on-site water and wastewater toxic analysis.
Co-reporter:Bingling Li, Yan Du, Tao Li, Shaojun Dong
Analytica Chimica Acta 2009 Volume 651(Issue 2) pp:234-240
Publication Date(Web):5 October 2009
DOI:10.1016/j.aca.2009.09.009
In this work, the suitability of 3,3′,5,5′-tetramethylbenzidine sulfate (TMB) as the substrate of a DNAzyme catalytic system composed of a guanine-quadruplex DNA molecule and hemin was investigated. In the presence of H2O2, the hemin–DNA complex catalyzes the oxidation of TMB to produce two colored products, much like a peroxidase. The color-generating activity of this system could be influenced by several factors such as buffer type, pH value, DNA sequence, reaction time, and concentrations of both the hemin and H2O2. To illustrate the utility of this catalytic system, we designed a colorimetric assay, in which a synthetic oligonucleotide with a sequence complementary to the G-quadruplex DNA was used as the target. A detection limit of 1.86 nM was obtained. Our data have shown that TMB was an excellent colorimetric indicator that reported the peoxidase activities of the widely studied hemin–G-quadruplex DNAzyme system.
Co-reporter:Lijian Huang, Yueming Zhai, Shaojun Dong, Jin Wang
Journal of Colloid and Interface Science 2009 Volume 331(Issue 2) pp:384-388
Publication Date(Web):15 March 2009
DOI:10.1016/j.jcis.2008.12.008
In the paper, we report an efficient method to prepare high yield (up to 97%) of silver nanoplates. Synthesis of silver nanoplates was carried out in a binary solvent system of N,NN,N-dimethylformamide (DMF) and toluene, in which DMF served as the reductant and polyvinylpyrrolidone (PVP) as the capping agent. By increasing the ratio of toluene to DMF to 7:6, silver nanoplates can be successfully synthesized; otherwise other shaped nanoparticles would be the major products. The nanoplate sample was characterized by TEM, HRTEM, SAED, XRD, AFM and UV–visible spectroscopy, proving the high nanoplate purity of this sample. The influence of toluene content, other solvents, AgNO3 concentration, preparation temperature and chloride ions was also examined, which suggests that the function of non-polar solvents in this system is to enhance the PVP coverage on silver surface and, furthermore, to facilitate the preferential adsorption of PVP on two (111) facets of silver nanoplates.TEM image and XRD pattern of a Ag nanoplate sample prepared by adding toluene as the co-solvent.
Co-reporter:Li Shang, Lihua Zhang and Shaojun Dong
Analyst 2009 vol. 134(Issue 1) pp:107-113
Publication Date(Web):20 Oct 2008
DOI:10.1039/B812458B
A new fluorescent sensor for the sensitive and selective detection of cyanide (CN−) in aqueous media was developed herein. The sensing approach is based on CN−-modulated quenching behavior of Cu2+ toward the photoluminescence (PL) of CdTe quantum dots (QDs). In the presence of CN−, the PL of QDs that have been quenched by Cu2+ was found to be efficiently recovered, which then allows the detection of CN− in a very simple approach. Experimental results showed that the pH of the buffer solution, concentration of copper ions, and size of CdTe QDs all influenced the response of the sensor to CN−. Under the optimal conditions, a good linear relationship between the PL intensity and the concentration of CN− can be obtained in the range of 3.0 × 10−7 to 1.2 × 10−5 M, with a detection limit as low as 1.5 × 10−7 M. In addition, the present fluorescent sensor possesses remarkable selectivity for cyanide over other anions, and negligible influences were observed on the cyanide detection by the coexistence of other anions or biological species (such as albumin and typical blood constituents). Therefore, we expect the proposed copper ion-modified QDs to be an efficient and reliable sensing system to monitor cyanide concentration in environmental or clinical applications.
Co-reporter:Tao Li;Lili Shi;Erkang Wang Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 4) pp:1036-1042
Publication Date(Web):
DOI:10.1002/chem.200801282
Abstract
Two significant G-quadruplex aptamers named AGRO100 and T30695 are identified as multifunctional aptamers that can bind the protein ligands nucleolin or HIV-1 integrase and hemin. Besides their strong binding to target proteins, both AGRO100 and T30695 exhibit high hemin-binding affinities comparable to that of the known aptamer (termed PS2M) selected by the in vitro evolution process. Most importantly, their corresponding hemin–DNA complexes reveal excellent peroxidase-like activities, higher than that of the reported hemin–PS2M DNAzyme. This enables these multifunctional aptamers to be applied to the sensitive detection of proteins, which is demonstrated by applying AGRO100 to the chemiluminescence detection of nucleolin expressed at the surface of HeLa cells. Based on the specific AGRO100–nucleolin interaction, the surface-expressed nucleolin of HeLa cells is labeled in situ with the hemin–AGRO100 DNAzyme, and then determined in the luminol–H2O2 system. Through this approach, the sensitive detection of total nucleolin expressed at the surface of about 6000 HeLa cells is accomplished. Our results suggest that exploiting new functions of existing aptamers will help to extend their potential applications in the biochemical field.
Co-reporter:Ming Zhou;Yuling Wang;Yueming Zhai;Junfeng Zhai;Wen Ren;Fuan Wang
Chemistry - A European Journal 2009 Volume 15( Issue 25) pp:6116-6120
Publication Date(Web):
DOI:10.1002/chem.200900596
Co-reporter:Tao Li;Lili Shi;Erkang Wang Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 14) pp:3347-3350
Publication Date(Web):
DOI:10.1002/chem.200900056
Co-reporter:Tao Li;Erkang Wang Dr.
Chemistry - A European Journal 2009 Volume 15( Issue 9) pp:2059-2063
Publication Date(Web):
DOI:10.1002/chem.200801825
Co-reporter:Dan Wen, Shaojun Guo, Junfeng Zhai, Liu Deng, Wen Ren and Shaojun Dong
The Journal of Physical Chemistry C 2009 Volume 113(Issue 30) pp:13023-13028
Publication Date(Web):July 2, 2009
DOI:10.1021/jp9003714
An easy surface-modified method has been developed to link −NH2 groups to the TiO2 colloidal spheres with nanoporous surface (f-TiO2). It was found that the as-prepared f-TiO2 is positively charged in neutral conditions and could act as an electrostatic anchor for nanosructures with opposite charge. Furthermore, platinum nanoparticles (Pt NPs) are successfully assembled on the f-TiO2 mainly via electrostatic interaction to fabricate a new kind of Pt NPs/TiO2 hybrid nanomaterial (f-TiO2−Pt NPs). The morphology, structure, and composition of the hybrids were characterized by the means of diverse techniques such as transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, and Raman spectra. Electrochemical experiments indicate the electrode modified with f-TiO2−Pt NPs shows prominent electrocatalytic activity toward the oxidation of hydrogen peroxide. In particular, as an example, a glucose biosensor fabricated by casting on additional glucose oxidase containing a biocompatible polymer, chitosan on the f-TiO2−Pt NPs film exhibits great promise for sensitive and fast detection of glucose.
Co-reporter:Li Shang, Jianyuan Yin, Jing Li, Lihua Jin, Shaojun Dong
Biosensors and Bioelectronics 2009 Volume 25(Issue 2) pp:269-274
Publication Date(Web):15 October 2009
DOI:10.1016/j.bios.2009.06.021
In this work, a new fluorescent method for sensitive detection of biological thiols in human plasma was developed using a near-infrared (NIR) fluorescent dye, FR 730. The sensing approach was based on the strong affinity of thiols to gold and highly efficient fluorescent quenching ability of gold nanoparticles (Au NPs). In the presence of thiols, the NIR fluorescence would enhance dramatically due to desorption of FR 730 from the surfaces of Au NPs, which allowed the analysis of thiol-containing amino acids in a very simple approach. The size of Au NPs was found to affect the fluorescent assay and the best response for cysteine detection was achieved when using Au NPs with the diameter of 24 nm, where a linear range of 2.5 × 10−8 M to 4.0 × 10−6 M and a detection limit of as low as 10 nM was obtained. This method also demonstrated a high selectivity to thiol-containing amino acids due to the strong affinity of thiols to gold. An important feature of the method is that the present fluorescent assay works in the NIR region, which is particularly favorable for the optical detection/imaging of biological samples. The method was successfully applied to the determination of thiols in a complex multicomponent mixture such as human plasma, which suggests our proposed method has great potential for diagnostic purposes.
Co-reporter:Ling Liu, Li Shang, Shaojun Guo, Dan Li, Changyu Liu, Li Qi, Shaojun Dong
Biosensors and Bioelectronics 2009 Volume 25(Issue 2) pp:523-526
Publication Date(Web):15 October 2009
DOI:10.1016/j.bios.2009.08.004
In this paper, organic–inorganic hybrid material, which is composed of silica and the grafting copolymer of poly (vinyl alcohol) and 4-vinylpyridine (PVA-g-P(4-VP)), was employed to immobilize Trichosporon cutaneum strain 2.570 cells. Cells entrapped into the hybrid material were found to keep a long-term viability. The mechanism of such a long-term viability was investigated by using confocal laser scanning microscopy (CLSM). Our studies revealed that arthroconidia produced in the extracellular material might play an important role in keeping the long-term viability of the immobilized microorganism. After the arthroconidia were activated, an electrochemical biochemical oxygen demand (BOD) sensor based on cell/hybrid material-modified supporting membrane was constructed for verifying the proposed mechanism. The results and insight gained from the present experiments can be widely used to various biosensor designs.
Co-reporter:Yan Du, Bingling Li, Fuan Wang, Shaojun Dong
Biosensors and Bioelectronics 2009 Volume 24(Issue 7) pp:1979-1983
Publication Date(Web):15 March 2009
DOI:10.1016/j.bios.2008.10.019
We report a sensitively amplified electrochemical aptasensor using adenosine triphosphate (ATP) as a model. ATP is a multifunctional nucleotide that is most important as a “molecular currency” of intracellular energy transfer. In the sensing process, duplexes consisting of partly complementary strand (PCS1), ATP aptamer (ABA) and another partly complementary strand (PCS2) were immobilized onto Au electrode through the 5′-HS on the PCS1. Meanwhile, PCS2 was grafted with the Au nanoparticles (AuNPs) to amplify the detection signals. In the absence of ATP, probe methylene blue (MB) bound to the DNA duplexes and also bound to guanine bases specifically to produce a strong differential pulse voltammetry (DPV) signal. But when ATP exists, the ABA-PCS2 or ABA-PCS1 part duplexes might be destroyed, which decreased the amount of MB on the electrode and led to obviously decreased DPV signal. This phenomenon can be used to detect ATP and get a very sensitive detection limit low to 0.1 nM, and the detection range could extend up to 10−7 M. Compared to the sensing platform without PCS2 grafted AuNPs, amplified function of this sensing system was also evidently proved. Therefore, such PCS1-ABA-PCS2/AuNPs sensing system could provide a promising signal-amplified model for aptamer-based small-molecules detection.
Co-reporter:Liu Deng, Lihua Zhang, Li Shang, Shaojun Guo, Dan Wen, Fuan Wang, Shaojun Dong
Biosensors and Bioelectronics 2009 Volume 24(Issue 7) pp:2273-2276
Publication Date(Web):15 March 2009
DOI:10.1016/j.bios.2008.10.031
We developed a stable, sensitive electrochemiluminescence (ECL) biosensor based on the synthesis of a new sol–gel material with the ion-exchange capacity sol–gel to coimmobilize the Ru(bpy)32+ and enzyme. The partial sulfonated (3-mercaptopropyl)-trimethoxysilane sol–gel (PSSG) film acted as both an ion exchanger for the immobilization of Ru(bpy)32+ and a matrix to immobilize gold nanoparticles (AuNPs). The AuNPs/PSSG/Ru(bpy)32+ film modified electrode allowed sensitive the ECL detection of NADH as low as 1 nM. Such an ability of AuNPs/PSSG/Ru(bpy)32+ film to promote the electron transfer between Ru(bpy)32+ and the electrode suggested a new, promising biocompatible platform for the development of dehydrogenase-based ECL biosensors. With alcohol dehydrogenase (ADH) as a model, we then constructed an ethanol biosensor, which had a linear range of 5 μM to 5.2 mM with a detection limit of 12 nM.
Co-reporter:Ming Zhou, Liu Deng, Dan Wen, Li Shang, Lihua Jin, Shaojun Dong
Biosensors and Bioelectronics 2009 Volume 24(Issue 9) pp:2904-2908
Publication Date(Web):15 May 2009
DOI:10.1016/j.bios.2009.02.028
This study demonstrates a novel compartment-less glucose/O2 biofuel cell (BFC) based on highly ordered mesoporous carbons (OMCs) with three-dimensionally (3D) interconnected and ordered pore structures. OMCs are used as supports for both stably confining the electrocatalyst (i.e., meldola's blue, MDB) for NADH oxidation and the anodic biocatalyst (i.e., NAD+-dependent glucose dehydrogenase, GDH) for glucose oxidation, and for facilitating direct electrochemistry of the cathodic biocatalyst (i.e., laccase, LAC) for O2 electroreduction. In 0.10 M pH 6.0 PBS containing 20 mM NAD+ and 60 mM glucose under the air-saturated atmosphere, the open circuit voltage (0.82 V) and the maximum power output (38.7 μW cm−2 (at 0.54 V)) of the assembled compartment-less OMCs-based BFC are both higher than those of carbon nanotubes (CNTs)-based BFC (0.75 V and 2.1 μW cm−2 (at 0.46 V)). These may make OMCs to be another kind of robust and advanced carbon electrode material besides CNTs for BFCs applications.
Co-reporter:Chang Liu, Ting Sun, Yueming Zhai, Shaojun Dong
Talanta 2009 Volume 78(Issue 2) pp:613-617
Publication Date(Web):30 April 2009
DOI:10.1016/j.talanta.2008.12.019
In this study, we report the effects of ferricyanide on organisms based on the changes in physiological state and morphology of Escherichia coli (E. coli) DH 5 α after being pretreated by ferricyanide. The impact on bacterial cell growth and viable rate of exposure to different concentrations of ferricyanide was determined, and the morphology change of E. coli was studied by atomic force microscopy (AFM). Finally, recovery test was used to evaluate the recovery ability of injured cells. The results showed that the effects on growth and morphology of E. coli were negligible when the concentration of ferricyanide was below 25.0 mM. While the results showed 50.8% inhibition of growth in the presence of 50.0 mM ferricyanide for 3 h, 89.6% viability was detected by flow cytometry (FCM) assay. AFM images proved that compact patches appeared on the bacterial surface and protected the bacterial viability. Furthermore, the results revealed that deterioration of bacterial surface closely related to the incubation time from 0.5 to 3 h at 100.0 mM ferricyanide. In the recovery test, microbial cell population and dissolved oxygen individually decreased 36.7% and 28.3% with 25.0 mM ferricyanide. These results clearly demonstrated that ferricyanide indeed affected viability of cells than morphology damaged, and the effects of toxin on bacteria were not reversible.
Co-reporter:Shaojun Guo, Dan Wen, Shaojun Dong, Erkang Wang
Talanta 2009 Volume 77(Issue 4) pp:1510-1517
Publication Date(Web):15 February 2009
DOI:10.1016/j.talanta.2008.09.042
Morphological control of nanomaterials is of great interest due to their size and shape-dependent chemical and physical properties and very important applications in many fields such as biomedicine, sensors, electronics and others. In this paper, we reported a simple strategy for synthesizing gold nanowire assembling architecture at room temperature. It is found that two important factors, the proper volume ratio of ethanol to water and poly(vinyl pyrrolidone) (PVP), will play important roles in synthesizing flower-like short gold nanowire assembling spheres. Furthermore, the obtained flower-like gold assembling spheres with high surface-to-volume ratio have been employed as enhancing materials for electrochemical sensing H2O2. The present electrochemical sensing platform exhibited good electrocatalytic activity towards the reduction of H2O2. The detection limit for H2O2 was found to be 1.2 μM, which was lower than certain enzyme-based biosensors.
Co-reporter:Li Shang, Shaojun Dong
Biosensors and Bioelectronics 2009 Volume 24(Issue 6) pp:1569-1573
Publication Date(Web):15 February 2009
DOI:10.1016/j.bios.2008.08.006
In this work, we report the application of novel, water-soluble fluorescent Ag clusters in fluorescent sensors for detecting cysteine, an important biological analyte. The fluorescence of poly(methacrylic acid) (PMAA)-templated Ag clusters was found to be quenched effectively by cysteine, but not when the other α-amino acids were present. By virtue of the specific response, a new, simple, and sensitive fluorescent method for detecting cysteine has been developed based on Ag clusters. The present assay allows for the selective determination of cysteine in the range of 2.5 × 10−8 to 6.0 × 10−6 M with a detection limit of 20 nM at a signal-to-noise ratio of 3. Based on the absorption and fluorescence studies, we suggested that cysteine quenched the emission by the thiol-adsorption-accelerated oxidation of the emissive Ag clusters. The present study shows a promising step toward the application of silver clusters, a new class of attractive fluorescence probes.
Co-reporter:Junfeng Zhai, Yueming Zhai, Shaojun Dong
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 Volume 335(1–3) pp:207-210
Publication Date(Web):5 March 2009
DOI:10.1016/j.colsurfa.2008.10.040
In this work, we studied the reaction between Au nanoparticles (Au NPs) and [Fe(CN)6]3− by the UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy. The absorption peak of Au NPs disappeared after adding [Fe(CN)6]3− and the XPS data conformed the formation of [Au(CN)2]−. The results demonstrated that [Fe(CN)6]3− could induce the dissolution of Au NPs, where the CN− from the dissociation of [Fe(CN)6]3− played an important role.
Co-reporter:Dan Wen, Xiangqin Zou, Ying Liu, Li Shang, Shaojun Dong
Talanta 2009 Volume 79(Issue 5) pp:1233-1237
Publication Date(Web):15 October 2009
DOI:10.1016/j.talanta.2009.05.025
Platinum nanoparticles (Pt NPs) were deposited onto multi-walled carbon nanotubes (MWNTs) through direct chemical reduction without any other stabilizing agents. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry were employed to characterize the morphology of the as-prepared nanocomposite (noted as Pt NPs–MWNTs) and further identify the Pt NPs on the surface of MWNTs. The nanocomposite demonstrated the ability to electrocatalyze the oxidation of hydrogen peroxide and substantially raises the response current. A sensitivity of 591.33 μA mM−1 cm−2 was obtained at Pt NPs–MWNTs modified electrode. Thus, we immobilized glucose oxidase (GOD) as a model enzyme on the nanocomposite-based electrode with a thin layer of Nafion to fabricate a glucose biosensor, which showed sensitive and fast response to glucose. The influence of the GOD loading was investigated and the biosensor with an enzyme loading concentration of 10 mg/mL shows optimal performance for glucose detection, that is, a detection limit of 3 μM and a response time of 3 s, respectively.
Co-reporter:Yueming Zhai, Junfeng Zhai, Yuling Wang, Shaojun Guo, Wen Ren and Shaojun Dong
The Journal of Physical Chemistry C 2009 Volume 113(Issue 17) pp:7009-7014
Publication Date(Web):2017-2-22
DOI:10.1021/jp810561q
A method to synthesize Fe3O4 core/Au shell submicrometer structures with very rough surfaces on the nanoscale is reported. The Fe3O4 particles were first modified with uniform polymers through the layer-by-layer technique and then adsorbed a lot of gold nanoseeds for further Au shell formation. The shell was composed of a large number of irregular nanoscale Au particles arranged randomly, and there were well-defined boundaries between these Au nanoparticles. The Fe3O4 core/Au shell particles showed strong plasmon resonance absorption in the near-infrared range, and can be separated quickly from solution by an external magnet. This kind of very rough Fe3O4 core/Au shell multicomponent was used in the adsorption of 4-aminothiophenol and as a substrate for detection by surface-enhanced Raman spectroscopy.
Co-reporter:Xiaoge Hu and Shaojun Dong
Journal of Materials Chemistry A 2008 vol. 18(Issue 12) pp:1279-1295
Publication Date(Web):11 Jan 2008
DOI:10.1039/B713255G
This review focuses on the synthesis, assembly, surface functionalization, as well as application of inorganic nanostructures. Electrochemical and wet-chemical methods are demonstrated to be effective approaches to make metal nanostructures under control without addition of a reducing agent or protecting agent. Owing to the unique physical and chemical properties of the nano-sized materials, novel applications are introduced using inorganic nanomaterials, such as electrocatalysis, photoelectricity, spectrochemistry, and analytical chemistry. This feature article provides detailed illustrations about the synthesis and assembly of metal nanostructures, surface modification of carbon nanotubes, as well as novel applications of inorganic nanomaterials, with an emphasis on metal nanostructures and carbon nanotubes derived from studies in the authors' laboratories.
Co-reporter:Li Shang and Shaojun Dong
Journal of Materials Chemistry A 2008 vol. 18(Issue 39) pp:4636-4640
Publication Date(Web):01 Sep 2008
DOI:10.1039/B810409C
In this work, we report the first application of water-soluble fluorescent Ag nanoclusters in fluorescent sensors. The fluorescence of poly(methacrylic acid) (PMAA)-templated Ag nanoclusters was found to be quenched effectively by Cu2+, but not when other common metal ions were present. By virtue of the specific response toward the analyte, a new, simple, and sensitive fluorescent method for detecting Cu2+ has been developed based on Ag nanoclusters. The present assay allows for the sensing of Cu2+ in the range of 1.0 × 10−8 M to 6.0 × 10−6 M with a detection limit as low as 8 nM at a signal-to-noise ratio of 3. The quenching mechanism was discussed based on the absorption and fluorescence spectroscopy studies, which suggested that Cu2+ quenched the emission by binding with the free carboxylic groups of PMAA polymers that surround the emissive Ag nanoclusters. In addition, the response of Ag nanoclusters toward Cu2+ was found to be reversible, which further made the present system attractive for sensor applications. The present study shows a promising step toward the application of fluorescent metal nanoclusters, which may also serve as a foundation for the further design and understanding of these novel materials.
Co-reporter:Fuan Wang, Jianlong Wang, Yueming Zhai, Gaiping Li, Dan Li, Shaojun Dong
Journal of Controlled Release 2008 Volume 132(Issue 1) pp:65-73
Publication Date(Web):24 November 2008
DOI:10.1016/j.jconrel.2008.08.016
In this work, we illustrate a simple chelation-based strategy to trigger DNA release from DNA-incorporated multilayer films, which were fabricated through the layer-by-layer (LbL) assembly of DNA and inorganic zirconium (IV) ion (Zr4+). After being incubated in several kinds of chelator solutions, the DNA multilayer films disassembled and released the incorporated DNA. This was most probably due to the cleavage of coordination/electrostatic interactions between Zr4+ and phosphate groups of DNA. Surface plasmon resonance (SPR), UV–vis spectrometry and atomic force microscopy (AFM) were used to characterize the assembly and the disassembly of the films. By incorporating plasmid DNA (pDNA) into this controllable disassembly system, the multilayer films sustained the consecutive DNA release. The released pDNA retained its integrity and transcriptional activity, and also expressed enhanced green fluorescent protein (EGFP) after being transfected into HEK 293 cells. Besides the simplicity and cost efficiency of this method, the most advantage of this route was that the release of DNA from the films could be modulated by various external conditions, such as the chelator and ionic strength. The Zr4+/DNA multilayer films with the ability to precisely control the release rate of DNA might serve as an alternative localized gene delivery system in the perspective of biomedical applications.
Co-reporter:Tao Li, Erkang Wang and Shaojun Dong
Chemical Communications 2008 (Issue 43) pp:5520-5522
Publication Date(Web):23 Sep 2008
DOI:10.1039/B809296F
With a designed high-activity DNAzyme as the catalytic label, an ultrasensitive chemiluminescence thrombin aptasensor is developed, enabling a 10- to 100-fold improvement in the detection sensitivity as compared with previous counterparts.
Co-reporter:Tie Wang, Xiaoge Hu and Shaojun Dong
Chemical Communications 2008 (Issue 38) pp:4625-4627
Publication Date(Web):04 Aug 2008
DOI:10.1039/B809736D
Spherical gold nanoparticles (3–5 nm) undergo a surprising fragmentation without extra energy imput and are converted into ultrasmall particles (less than 1.5 nm), which is a direct result of electron transfer between gold nanoparticles and cysteine.
Co-reporter:Tao Li, Erkang Wang and Shaojun Dong
Chemical Communications 2008 (Issue 31) pp:3654-3656
Publication Date(Web):09 Jun 2008
DOI:10.1039/B805565C
Thrombin-binding aptamer is found to bind hemin to form a catalytic complex whose activity is significantly promoted by the addition of thrombin, which enables the colorimetric detection of thrombin with high specificity and sensitivity in a facile way.
Co-reporter:Yuling Wang, Dan Li, Wen Ren, Zuojia Liu, Shaojun Dong and Erkang Wang
Chemical Communications 2008 (Issue 22) pp:2520-2522
Publication Date(Web):31 Mar 2008
DOI:10.1039/B801055B
A simple, rapid and ultrasensitive colorimetric detection of protein using aptamer–Au nanoparticles (AuNPs) conjugates based on a dot-blot array has been developed, which was combined with the unique optical properties of AuNPs, enabling the visual detection of protein within minutes without any instrument.
Co-reporter:Li Shang and Shaojun Dong
Chemical Communications 2008 (Issue 9) pp:1088-1090
Publication Date(Web):10 Jan 2008
DOI:10.1039/B717728C
We report a new approach for the synthesis of fluorescent and water-soluble Ag nanoclusters, using the common polyelectrolyte poly(methacrylic acid) as the template.
Co-reporter:Junfeng Zhai, Yueming Zhai, Liang Wang and Shaojun Dong
Inorganic Chemistry 2008 Volume 47(Issue 16) pp:7071-7073
Publication Date(Web):July 23, 2008
DOI:10.1021/ic800941d
Polyethylenimine (PEI)-protected Prussian blue nanocubes have been simply synthesized by heating an acidic mixture of PEI, FeCl3, K3Fe(CN)6, and KCl. The experiment results presented here demonstrate that the pH of the mixture plays an important role in controlling the shape and composition of the resultant product.
Co-reporter:Liang Wang, Shaojun Guo, Junfeng Zhai and Shaojun Dong
The Journal of Physical Chemistry C 2008 Volume 112(Issue 35) pp:13372-13377
Publication Date(Web):2017-2-22
DOI:10.1021/jp804484f
A very simple and effective wet chemical route to direct synthesis of well-dispersed Pt nanoparticles with urchinlike morphology is proposed, which was carried out by simply mixing H2PtCl6 aqueous solution and poly(vinyl pyrrolidone) with the initial molar ratios of 1:3.5 kept constant at 30 °C for 3 days in the presence of formic acid. As-prepared urchinlike Pt nanostructures showed excellent electrocatalytic activity toward the reduction of dioxygen and oxidation of methanol and could be used as a promising nanoelectrocatalyst.
Co-reporter:Tie Wang, Xiaoge Hu, Jianlong Wang, Shaojun Dong
Talanta 2008 Volume 75(Issue 2) pp:455-460
Publication Date(Web):15 April 2008
DOI:10.1016/j.talanta.2007.11.033
A useful method for the fabrication of three-dimensional gold nanowire networks based on the chemical reduction of HAuCl4 with trisodium citrate was presented. The coverage of the 3D gold nanowire networks was tunable by altering precursor concentration. The as-prepared 3D gold nanowire networks could be used as surface-enhanced Raman scattering (SERS) substrates and examined by 4-aminothiophenol (4-ATP) as a probe molecules. Since the proposed strategy is simple, cost-effective and reproducible for the mass production of network-like gold films irrespective of the kinds of the underlying substrates, it is expected to play an important role in the development of surface plasmon-based analytical devices.
Co-reporter:Bingling Li, Yuling Wang, Hui Wei, Shaojun Dong
Biosensors and Bioelectronics 2008 Volume 23(Issue 7) pp:965-970
Publication Date(Web):28 February 2008
DOI:10.1016/j.bios.2007.09.019
Here, we report a sensitive amplified electrochemical impedimetric aptasensor for thrombin, a kind of serine protease that plays important role in thrombosis and haemostasis. For improving detection sensitivity, a sandwich sensing platform is fabricated, in which the thiolated aptamers are firstly immobilized on a gold substrate to capture the thrombin molecules, and then the aptamer functionalized Au nanoparticles (AuNPs) are used to amplify the impedimetric signals. Such designed aptamer/thrombin/AuNPs sensing system could not only improve the detection sensitivity compared to the reported impedimetric aptasensors but also provide a promising signal amplified model for aptamer-based protein detection. In this paper, we realize a sensitive detection limit of 0.02 nM, with a linear range of 0.05–18 nM. Meanwhile, the effect of 6-mercaptohexanol (MCH) and 2-mercaptoethanol (MCE) on the modification of the electrode is investigated.
Co-reporter:Shaojun Guo ;Erkang Wang
Chemistry - A European Journal 2008 Volume 14( Issue 15) pp:4689-4695
Publication Date(Web):
DOI:10.1002/chem.200800077
Abstract
We have reported a facile and general method for the rapid synthesis of hollow nanostructures with urchinlike morphology. In-situ produced Ag nanoparticles can be used as sacrificial templates to rapidly synthesize diverse hollow urchinlike metallic or bimetallic (such as Au/Pt) nanostructures. It has been found that heating the solution at 100 °C during the galvanic replacement is very necessary for obtaining urchinlike nanostructures. Through changing the molar ratios of Ag to Pt, the wall thickness of hollow nanospheres can be easily controlled; through changing the diameter of Ag nanoparticles, the size of cavity of hollow nanospheres can be facilely controlled; through changing the morphologies of Ag nanostructures from nanoparticle to nanowire, hollow Pt nanotubes can be easily designed. This one-pot approach can be extended to synthesize other hollow nanospheres such as Pd, Pd/Pt, Au/Pd, and Au/Pt. The features of this technique are that it is facile, quick, economical, and versatile. Most importantly, the hollow bimetallic nanospheres (Au/Pt and Pd/Pt) obtained here exhibit an area of greater electrochemical activity than other Pt hollow or solid nanospheres. In addition, the ≈6 nm hollow urchinlike Pt nanospheres can achieve a potential of up to 0.57 V for oxygen reduction, which is about 200 mV more positive than that obtained by using a ≈6 nm Pt nanoparticle modified glassy carbon (GC) electrode. Rotating ring-disk electrode (RRDE) voltammetry demonstrates that ≈6 nm hollow Pt nanospheres can catalyze an almost four-electron reduction of O2 to H2O in air-saturated H2SO4 (0.5 M). Finally, compared to the ≈6 nm Pt nanoparticle catalyst, the ≈6 nm hollow urchinlike Pt nanosphere catalyst exhibits a superior electrocatalytic activity toward the methanol oxidation reaction at the same Pt loadings.
Co-reporter:Fuan Wang, Dan Li, Gaiping Li, Xiaoqing Liu and Shaojun Dong
Biomacromolecules 2008 Volume 9(Issue 10) pp:
Publication Date(Web):August 28, 2008
DOI:10.1021/bm800766t
A layer-by-layer film composed of DNA and inorganic zirconium ion (Zr4+) was fabricated on the surface of gold thin film, and an electric field triggered disintegration of the multilayer film was studied by using electrochemical surface plasmon resonance (EC-SPR). EC-SPR results demonstrated that the film was disassembled upon the application of an electric field and the disassembly rate varied with the applied potential, leading to the controlled release of DNA. The electrodissolution could be switched off by removing the electric potential and reactivated by reapplying the potential. By incorporating plasmid DNA (pDNA) in to this controlled release system, the multilayer film could sustain the consecutive release of pDNA electrochemically. The released pDNA retained its integrity and transfection activity, and expressed enhanced green fluorescent protein (EGFP) after being transfected into HEK 293 cells. The electrochemical systems, with advantages of miniaturization, surface-tailoring, safety, simplicity, convenience, automation, low-cost, and free of immune reactions, made the electrical route a very attractive gene-delivery alternative.
Co-reporter:Tie Wang, Xiaoge Hu and Shaojun Dong
Journal of Materials Chemistry A 2007 vol. 17(Issue 39) pp:4189-4195
Publication Date(Web):06 Aug 2007
DOI:10.1039/B707481F
Functionalized multiwalled carbon nanotubes (MWNTs) were selected as cross-linkers to construct three-dimensional (3D) porous nanoparticle/MWNT hybrid nanostructures by “bottom-up” self-assembly. The resultant 3D hybrid nanostructure was different from that of metal nanoparticle multilayer assemblies prepared by traditional routes using small molecules or polymers as cross-linkers. The rigidity of the MWNTs resulted in only partial coverage of the nanoparticle surfaces between the linkers during the growth of multilayer film, providing more accessible surfaces to allow target molecules to adsorb on to and react with. HRP was used as a simple model to study the porosity of this assembly.
Co-reporter:Yuling Wang, Hui Wei, Bingling Li, Wen Ren, Shaojun Guo, Shaojun Dong and Erkang Wang
Chemical Communications 2007 (Issue 48) pp:5220-5222
Publication Date(Web):16 Oct 2007
DOI:10.1039/B709492B
SERS aptasensors for protein recognition based on Au nanoparticles labeled with aptamers and Raman reporters have been developed, which opens a new way for protein recognition of high sensitivity and selectivity.
Co-reporter:Bingling Li, Yan Du, Hui Wei and Shaojun Dong
Chemical Communications 2007 (Issue 36) pp:3780-3782
Publication Date(Web):09 Jul 2007
DOI:10.1039/B707057H
We report a sensitive electrochemical aptasensor for adenosine based on electrochemical impedance spectroscopy measurement, which gives not only a label-free but also a reusable platform to make the detection of small molecules simple and convenient.
Co-reporter:Tie Wang, Xiaoge Hu and Shaojun Dong
Chemical Communications 2007 (Issue 18) pp:1849-1851
Publication Date(Web):13 Feb 2007
DOI:10.1039/B616778K
Herein, we describe a simple and inexpensive method for forming superhydrophobic cloths with the highest water contact angle of close to 180°, in which normal commercial cloths serving as pristine materials are modified with suitable gold micro/nanostructures.
Co-reporter:Bingling Li, Hui Wei and Shaojun Dong
Chemical Communications 2007 (Issue 1) pp:73-75
Publication Date(Web):22 Nov 2006
DOI:10.1039/B612080F
We report an aptamer-based method for the sensitive detection of proteins by a label-free fluorescing molecular switch (ethidium bromide), which shows promising potential in making protein assay simple and economical.
Co-reporter:Hui Wei, Bingling Li, Jing Li, Erkang Wang and Shaojun Dong
Chemical Communications 2007 (Issue 36) pp:3735-3737
Publication Date(Web):29 Jun 2007
DOI:10.1039/B707642H
We describe herein simple and sensitive aptamer-based colorimetric sensing of protein (alpha-thrombin in this work) using unmodified gold nanoparticle probes.
Co-reporter:Shaojun Guo, Xiaohu Qu, Shaojun Dong
Electrochimica Acta 2007 Volume 52(Issue 20) pp:6186-6191
Publication Date(Web):10 June 2007
DOI:10.1016/j.electacta.2007.04.018
A method for preparing nanoelectrode ensembles based on semi-interpenetrating network (SIN) of multi-walled carbon nanotubes (MWNTs) on gold electrode through phase-separation method is initially proposed. Individual nanoelectrode owns irregular three-dimensional MWNTs networks, which is denoted as SIN–MWNTs. On the as-prepared SIN–MWNTs nanoelectrode ensembles, the assembled MWNTs clusters in nanoscale serve as individual nanoelectrode and the electroinactive lipid networks located on the top of alkanethiol monolayer are used as a shielding layer. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), tapping-mode atomic force microscopy (TM-AFM) and scanning electron microscopy (SEM) were used to characterize the as-prepared SIN–MWNT nanoelectrode ensembles. Experimental results indicate that the well-defined nanoelectrode ensembles were prepared through self-assembly technology. Meantime, sigmoid curves in a wide scanning range can be obtained in CV experiments. This study may pave the way for the construction of truly nanoscopic nanoelectrode arrays by bottom-up strategy.
Co-reporter:Hongjun Chen, Yuling Wang, Ying Liu, Yizhe Wang, Li Qi, Shaojun Dong
Electrochemistry Communications 2007 Volume 9(Issue 3) pp:469-474
Publication Date(Web):March 2007
DOI:10.1016/j.elecom.2006.10.019
The composite film based on Nafion and hydrophobic room-temperature ionic liquid (RTIL) 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim] PF6) was explored. Here, Nafion was used as a binder to form Nafion-ionic liquids composite film and help [bmim] PF6 effectively adhered on glassy carbon (GC) electrode. X-ray photoelectron spectroscopy (XPS), cyclic voltammtery (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize this composite film, showing that the composite film can effectively adhere on the GC electrode surface through Nafion interacting with [bmim] PF6 and GC electrode. Meanwhile, doping [bmim] PF6 in Nafion can also effectively reduce the electron transfer resistance of Nafion. The composite film can be readily used as an immobilization matrix to entrap horseradish peroxidase (HRP). A pair of well-defined redox peaks of HRP was obtained at the HRP/Nafion-[bmim] PF6 composite film-modified GC electrode through direct electron transfer between the protein and the underlying electrode. HRP can still retain its biological activity and enhance electrochemical reduction towards O2 and H2O2. It is expected that this composite film may find more potential applications in biosensors and biocatalysis.
Co-reporter:Xiangqin Zou, Erbo Ying, Shaojun Dong
Journal of Colloid and Interface Science 2007 Volume 306(Issue 2) pp:307-315
Publication Date(Web):15 February 2007
DOI:10.1016/j.jcis.2006.10.084
Novel silver–gold bimetallic nanostructures were prepared by seeding with silver nanoplates in the absence of any surfactants. During the synthesis process, it was found that the frameworks of silver nanoplates were normally kept though the basal plane of silver nanoplates became rugged. The real morphology of these nanostructures depended on the molar ratio of gold ions to the seed particles. When the molar ratio of gold ions to silver atoms increased from 0.5 to 4, porous or branched silver–gold bimetallic nanostructures could be made. The growth mechanism was qualitatively discussed based on template-engaged replacement reactions and seed-mediated deposition reactions. Due to the unusual structures, they exhibited interesting optical properties. Moreover, they were shown to be an active substrate for surface-enhanced Raman scattering measurements.
Co-reporter:Xiaoge Hu, Tie Wang, Shaojun Dong
Journal of Colloid and Interface Science 2007 Volume 316(Issue 2) pp:947-953
Publication Date(Web):15 December 2007
DOI:10.1016/j.jcis.2007.09.023
Three-dimensional Au nanorod and Au nanoparticle nanostructured materials were prepared by layer-by-layer self-assembly. The plasmonic properties of the Au nanorod and Au nanoparticle self-assembled nanostructured materials (abbreviated as AuNR and AuNP SANMs) are tunable by the controlled self-assembly process. The effect of thermal annealing at 180 and 500 °C to the morphologies, plasmonic properties and surface-enhanced Raman scattering (SERS) responses of these SANMs were investigated. According to the experimental results, these properties correlate with the structure of the SANMs.
Co-reporter:Li Qi
Journal of Applied Polymer Science 2007 Volume 104(Issue 1) pp:
Publication Date(Web):25 JAN 2007
DOI:10.1002/app.25610
Using the copolymer of acrylonitrile (AN), methyl methacrylate (MMA), and poly(ethylene glycol) methyl ether methacrylate as a backbone and poly(ethylene glycol) methyl ether (PEGME) with 1100 molecular weight as side chains, comb-like gel polymers and their Li salt complexes were synthesized. The dynamic mechanical properties and conductivities were investigated. Results showed that the gel copolymer electrolytes possess two glass transitions: α-transition and β-transition. Based on the time–temperature equivalence principle, a master curve was constructed by selecting Tα as reference temperature. By reference to T0 = 50°C, the relation between log τc and c was found to be linear. The master curves are displaced progressively to higher frequencies as the content of plasticizer is increased. The relation between log τp and the content of plasticizer is also linear. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 576–584, 2007
Co-reporter:Tao Li;Bingling Li Dr.;Erkang Wang Dr.
Chemistry - A European Journal 2007 Volume 13(Issue 30) pp:
Publication Date(Web):18 JUL 2007
DOI:10.1002/chem.200700275
Herein, we report an approach for protein detection enhanced by ionic liquid (IL) selectors in capillary electrophoresis (CE), with avidin as a model protein. Hydrophilic ILs were added into the running buffer of CE and acted as selectors for sample injection, enriching the positive target and excluding the negative from the capillary. When using 3 % (v/v) IL selector, the detection sensitivity of avidin was improved by over one order of magnitude, while the interference from protein adsorption was effectively avoided, even in an uncoated capillary. The electrochemiluminescence method was initially used for IL-based CE with low noise that was independent of the IL concentration, making ILs almost transparent as additives in the electrophoresis buffer.
Co-reporter:Tao Li Dr.;Bingling Li Dr. Dr.
Chemistry - A European Journal 2007 Volume 13(Issue 23) pp:
Publication Date(Web):15 MAY 2007
DOI:10.1002/chem.200700068
We report a novel label-free method for the investigation of the adaptive recognition of small molecules by nucleic acid aptamers using capillary electrophoresis analysis. Cocaine and argininamide were chosen as model molecules, and the two corresponding DNA aptamers were used. These single-strand DNAs folded into their specific secondary structures, which were mainly responsible for the binding of the target molecules with high affinity and specificity. For molecular recognition, the nucleic acid structures then underwent additional conformational changes, while keeping the target molecules stabilized by intermolecular hydrogen bonds. The intrinsic chemical and physical properties of the target molecules enabled them to act as indicators for adaptive binding. Thus any labeling or modification of the aptamers or target molecules were made obsolete. This label-free method for aptamer-based molecular recognition was also successfully applied to biological fluids and therefore indicates that this approach is a promising tool for bioanalysis.
Co-reporter:Minghua Huang, Heqing Jiang, Junfeng Zhai, Baifeng Liu, Shaojun Dong
Talanta 2007 Volume 74(Issue 1) pp:132-139
Publication Date(Web):15 November 2007
DOI:10.1016/j.talanta.2007.05.042
Through a new and simple ion-exchange route, two-electron redox mediator thionine has been deliberately incorporated into the carbon nanotubes (CNTs)/Nafion composite film due to the fact that there is strong interaction between any of two among the three materials (ion-exchange process between thionine and Nafion, strong adsorption of thionine by CNTs, and wrapping and solubilizing of CNTs with Nafion). The good homogenization of electron conductor CNTs in the integrated films provides the possibility of three-dimensional electron conductive network. The resulting integrated films exhibited high and stable electrocatalytic activity toward NADH oxidation with the significant decrease of high overpotential, which responds more sensitively more than those modified by thioine or CNTs alone. Such high electrocatalytic activity facilitated the low potential determination of NADH (as low as −0.1 V), which eliminated the interferences from other easily oxidizable species. In a word, the immobilization approach is very simple, timesaving and effective, which could be extended to the immobilization of other cationic redox mediators into the CNTs/Nafion composite film. And these features may offer potential promise for the design of amperometric biosensors.
Co-reporter:Hongjun Chen, Shaojun Dong
Talanta 2007 Volume 71(Issue 4) pp:1752-1756
Publication Date(Web):15 March 2007
DOI:10.1016/j.talanta.2006.08.014
Gold nanoparticles in polyelectrolyte multilayers film can be easily prepared by repeating immersion of a substrate in poly(diallyl dimethylammonium) chloride (PDDA)-AuCl4− complexes solution followed by reduction Au3+ through heating. UV–vis spectroscopy, cyclic voltammetry (CV) and tapping-mode atomic force microscopy (AFM) are used to confirm the successful construction of the polyelectrolyte multilayers film and the formation of gold nanoparticles. The multilayers film shows electrocatalytic activity to dioxygen reduction.
Co-reporter:Hongjun Chen, Shaojun Dong
Biosensors and Bioelectronics 2007 Volume 22(Issue 8) pp:1811-1815
Publication Date(Web):15 March 2007
DOI:10.1016/j.bios.2006.08.013
The sol–gel-derived ceramic–carbon nanotube (SGCCN) nanocomposite film fabricated by doping multiwall carbon nanotubes (MWNTs) into a silicate gel matrix was used to immobilize protein. The SGCCN film can provide a favorable microenvironment for horseradish peroxidase (HRP) to perform direct electron transfer (DET) at glassy carbon electrode. The HRP immobilized in the SGCCN film shows a pair of well-defined redox waves and retains its bioelectrocatalytic activity to the reduction of O2 and H2O2, which is superior to that immobilized in silica sol–gel film.
Co-reporter:Xuping Sun Dr.;Lixue Zhang;Yan Du ;Erkang Wang
Chemistry – An Asian Journal 2007 Volume 2(Issue 9) pp:1137-1141
Publication Date(Web):6 JUL 2007
DOI:10.1002/asia.200700002
Tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy)3]2+) is one of the most extensively studied and used electrochemiluminescent (ECL) compounds owing to its superior properties, which include high sensitivity and stability under moderate conditions in aqueous solution. In this paper we present a simple method for the preparation of [Ru(bpy)3]2+-containing microstructures based on electrostatic assembly. The formation of such microstructures occurs in a single process by direct mixing of aqueous solutions of [Ru(bpy)3]Cl2 and K3[Fe(CN)6] at room temperature. The electrostatic interactions between [Ru(bpy)3]2+ cations and [Fe(CN)6]3− anions cause them to assemble into the resulting microstructures. Both the molar ratio and concentration of reactants were found to have strong influences on the formation of these microstructures. Most importantly, the resulting [Ru(bpy)3]2+-containing microstructures exhibit excellent ECL behavior and, therefore, hold great promise for solid-state ECL detection in capillary electrophoresis (CE) or CE microchips.
Co-reporter:Lihua Zhang, Zhiai Xu, Shaojun Dong
Analytica Chimica Acta 2006 Volume 575(Issue 1) pp:52-56
Publication Date(Web):4 August 2006
DOI:10.1016/j.aca.2006.05.069
A new electrogenerated chemiluminescence biosensor was fabricated by immobilizing ECL reagent Ru(bpy)32+ and alcohol dehydrogenase in sol–gel/chitosan/poly(sodium 4-styrene sulfonate) (PSS) organically modified composite material. The component PSS was used to immobilize ECL reagent Ru(bpy)32+ by ion-exchange, while the addition of chitosan was to prevent the cracking of conventional sol–gel-derived glasses and provide biocompatible microenvironment for alcohol dehydrogenase. Such biosensor combined enzymatic selectivity with the sensitivity of ECL detection for quantification of enzyme substrate and it was much simpler than previous double-layer design. The detection limit was 9.3 × 10−6 M for alcohol (S/N = 3) with a linear range from 2.79 × 10−5 to 5.78 × 10−2 M. With ECL detection, the biosensor exhibited wide linear range, high sensitivity and good stability.
Co-reporter:Xuping Sun, Shaojun Dong, Erkang Wang
Materials Chemistry and Physics 2006 Volume 96(Issue 1) pp:29-33
Publication Date(Web):10 March 2006
DOI:10.1016/j.matchemphys.2005.06.046
Polyelectrolytes have been widely used as building blocks for the creation of thickness-controllable multilayer thin films in a layer-by-layer fashion, and also been used as flocculants or stabilizer of colloids. This paper reports novel finding that a kind of polyelectrolyte, polyamines, can facilely induce HAuCl4 to spontaneously form well-stabilized gold nanoparticles without the additional step of introducing a reducing reagent during the elevation of temperature, even at room temperature in some cases. The polymer chain-confined microenvironment and the acid-induced evolution of amide of such kind of polyelectrolyte solution play an important role in the nucleation and growth of gold nanoparticles. This method would not only be helpful to gain an insight into the formation of gold nanoparticles in polyelectrolyte systems, but also provide a novel and facile one-step polyelectrolyte-based synthetic route to polyelectrolyte protected gold nanoparticles in aqueous media for potential applications. More importantly, this strategy will be general to the preparation of other nanoparticles.
Co-reporter:Hongjun Chen, Yuling Wang, Shaojun Dong, Erkang Wang
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2006 Volume 64(Issue 2) pp:343-348
Publication Date(Web):15 May 2006
DOI:10.1016/j.saa.2005.07.058
In this paper, an approach for fabricating an active surface-enhanced Raman scattering (SERS) substrate is adopted. This approach is based on the assembling of silver nanoparticles film on gold substrate. Rhodamine 6G (R6G) and p-aminothiophenol (p-ATP) were used as probe molecules for SERS experiments, showing that this new active substrate has sensitivity to SERS response. Tapping-mode atomic force microscopy (AFM) was also used to investigate the surface morphology following the fabricating process of the active SERS substrate, which showed that large quantities of silver nanoparticles were uniformly coated on the substrate.
Co-reporter:Minghua Huang, Heqing Jiang, Xiaohu Qu, Zhiai Xu, Yuling Wang and Shaojun Dong
Chemical Communications 2005 (Issue 44) pp:5560-5562
Publication Date(Web):10 Oct 2005
DOI:10.1039/B508130K
Electroactive and photoactive thionine molecules have been selected as cross-linkers to construct self-assembled multilayers containing carbon nanotubes (CNTs)
via the alternate layer deposition technique. The resulting multilayer system can electrocatalyze the oxidation of NADH and offer potential applications in other fields such as biosenors and photovoltaic devices.
Co-reporter:Mingkui Wang, Li Qi, Feng Zhao, Shaojun Dong
Journal of Power Sources 2005 Volume 139(1–2) pp:223-229
Publication Date(Web):4 January 2005
DOI:10.1016/j.jpowsour.2004.06.060
Polymer electrolytes, which comprise a novel comb-like copolymer and an alkali metal salt, were successfully prepared and discussed using differential scanning calorimeter, Fourier transform infrared spectroscopy, nuclear magnetic resonance, atom force microscopy, and electrochemical impedance spectroscopy. The novel comb-like copolymer is capable of forming donor:acceptor type bonds with alkali metal ions. The complex system with a mixture of fumed silica or propylene carbonate was studied also. Such electrolytes possess satisfactory ambient temperature ionic conductivity (up to 10−4 S cm−1) and good mechanical strength. The Vogel–Tamman–Fulcher-like behavior of conductivity implies the coupling of the charge carriers with the segmental motion of the polymer chains.
Co-reporter:Xuping Sun;Erkang Wang;Erkang Wang;Xuping Sun
Macromolecular Rapid Communications 2005 Volume 26(Issue 18) pp:1504-1508
Publication Date(Web):8 SEP 2005
DOI:10.1002/marc.200500502
Summary: Uniform one-dimensional (1D) structures of o-phenylenediamine (oPD) oligomers are obtained by direct mix of AgNO3 and oPD aqueous solutions at room temperature. The formation of the 1D structures involves two stages: (1) oxidation of oPD by AgNO3, yielding individual oPD oligomers; and (2) self-assembly of the oligomers, forming the 1D structures. Upon decreasing medium pH, the 1D structures can break-apart to form individual oligomers, or vice versa. It is also found that both the concentration and molar ratio of reactants can influence the morphology of the structures thus formed.
Co-reporter:Haifeng Bao, Zhangquan Peng, Yongdong Jin, Shaojun Dong and Erkang Wang
New Journal of Chemistry 2005 vol. 29(Issue 8) pp:1004-1006
Publication Date(Web):16 Jun 2005
DOI:10.1039/B500721F
A fork-like molecule can induce citrate-capped gold nanoparticles of 2.6 nm diameters to form sintered peanut-like nanoarrays and aggregates. The formation of such aggregates is size-dependent because of steric hindrance between the fork-like molecule and the 5 nm or bigger Au nanoparticles.
Co-reporter:Wenlong Cheng ;Erkang Wang
Angewandte Chemie 2003 Volume 115(Issue 4) pp:
Publication Date(Web):28 JAN 2003
DOI:10.1002/ange.200390104
Iod als Leim für Nanoaggregate: Mit der spontanen Chemisorption von Iod auf Gold-Nanopartikeln geht eine Elektroneninjektion von Iod auf Gold einher, was zur Fusion der Nanopartikel und schließlich zur Aggregation führt; ein Überschuss an KI führt zur Bildung von Nanokristallen (siehe Schema). Oberflächengebundene und „iodverleimte“ Aggregate dieser Art können auf einem aminofunktionalisierten festen Träger durch schrittweise Derivatisierung mit kolloidal verteiltem Gold und KI-Lösung aufgebaut werden.
Co-reporter:Wenlong Cheng ;Erkang Wang
Angewandte Chemie International Edition 2003 Volume 42(Issue 4) pp:
Publication Date(Web):28 JAN 2003
DOI:10.1002/anie.200390136
Iodine glue! Spontaneous iodine chemisorption on gold nanoparticles is demonstrated. The concomitant electron injection into gold nanoparticles results in particle fusion, fragmentation, and aggregation, excess KI addition leads to the formation of nanocrystals (see scheme). Surprisingly, iodine-“glued” surface-bound nanostructured assemblies of gold nanoparticles can be constructed on an amino-functionalized solid support by stepwise derivatization with colloidal Au and KI solution.
Co-reporter:Haiyan Wang, Guobao Xu, Shaojun Dong
Talanta 2001 Volume 55(Issue 1) pp:61-67
Publication Date(Web):3 August 2001
DOI:10.1016/S0039-9140(01)00406-4
An electrochemically stable monolayer of tris(2,2′-bipyridyl)ruthenium(II) was obtained for the first time. It was based on the electrostatic attachment of Ru(bpy)32+ to the benzene sulfonic acid monolayer film, which was covalently bound onto glassy carbon electrode by the electrochemical reduction of diazobenzene sulfonic acid. The surface–confined Ru(bpy)32+ underwent reversible surface process, and reacted with the coreactant, tripropylamine, to produce electrochemiluminescence. In view of the stability of the electrode, the results strongly suggested that light was emitted from the surface–confined Ru(bpy)32+, not from the detached Ru(bpy)32+. The Ru(bpy)32+ modified electrode was used to the determination of tripropylamine. It showed good linearity in the concentration range from 5 μM to 1 mM with a detection limit of 1 μM (S/N=4). The good stability of the Ru(bpy)32+ modified electrode also showed that the benzene sulfonic acid monolayer film prepared can be served as an excellent support to construct multilayers.
Co-reporter:Shaojun Guo and Shaojun Dong
Journal of Materials Chemistry A 2011 - vol. 21(Issue 46) pp:NaN18516-18516
Publication Date(Web):2011/10/04
DOI:10.1039/C1JM13228H
Graphene, a new material for which the Noble prize was won, has received increasing attention due to its unique physicochemical properties, such as a high surface area, excellent conductivity, a high mechanical strength, and good biocompatibility. In particular, in the last two years there has been explosive growth in studies relating to the use of graphene and its derivatives as enhanced materials or carriers for probes and recognition elements in the development of high-performance analytical devices. In this feature article, we will highlight recent important progress in the construction of graphene and its derivative-based high-performance analytical sensors. First, recent research efforts on the design of new electrochemical sensors, including amperometry, electrochemical luminescence (ECL), field-effect transistor (FET), electrochemical impedance, photoelectrochemical and surface plasmon resonance (SPR) electrochemical sensors are described. Then, we will move on to discuss more modish optical sensors, such as fluorescent, colorimetric and surface enhanced Raman spectroscopy (SERS) sensors. Finally, we conclude with a look at the future challenges and prospects of graphene and its derivative-related analytical devices.
Co-reporter:Chengzhou Zhu, Shaojun Guo, Ping Wang, Li Xing, Youxing Fang, Yueming Zhai and Shaojun Dong
Chemical Communications 2010 - vol. 46(Issue 38) pp:NaN7150-7150
Publication Date(Web):2010/07/23
DOI:10.1039/C0CC01459A
A novel and facile process is reported for water-phase synthesis of high-quality graphene/TiO2 composite nanosheets (GTCN) on a large scale using TiCl3 as both a reducing agent and a precursor.
Co-reporter:Chengzhou Zhu, Shaojun Guo and Shaojun Dong
Journal of Materials Chemistry A 2012 - vol. 22(Issue 30) pp:
Publication Date(Web):
DOI:10.1039/C2JM32663A
Co-reporter:Tie Wang, Xiaoge Hu and Shaojun Dong
Chemical Communications 2008(Issue 38) pp:NaN4627-4627
Publication Date(Web):2008/08/04
DOI:10.1039/B809736D
Spherical gold nanoparticles (3–5 nm) undergo a surprising fragmentation without extra energy imput and are converted into ultrasmall particles (less than 1.5 nm), which is a direct result of electron transfer between gold nanoparticles and cysteine.
Co-reporter:Lihua Jin, Youxing Fang, Li Shang, Yaqing Liu, Jing Li, Li Wang, Peng Hu and Shaojun Dong
Chemical Communications 2013 - vol. 49(Issue 3) pp:NaN245-245
Publication Date(Web):2012/11/22
DOI:10.1039/C2CC36316J
A highly robust electrochemically controlled fluorescence switch based on ultrasmall Au nanoclusters has been designed by the aid of the electrochemical redox reaction of prussian blue.
Co-reporter:Yanling Zhai, Chengzhou Zhu, Jiangtao Ren, Erkang Wang and Shaojun Dong
Chemical Communications 2013 - vol. 49(Issue 24) pp:NaN2402-2402
Publication Date(Web):2012/12/21
DOI:10.1039/C2CC38292J
We report a novel design, based on a combination of lanthanide-doped upconversion nanoparticles and polyoxometalates, for electrically controlled fluorescence switches and sensitive detection of antioxidants in aqueous solution.
Co-reporter:Tao Li, Bingling Li, Erkang Wang and Shaojun Dong
Chemical Communications 2009(Issue 24) pp:NaN3553-3553
Publication Date(Web):2009/05/07
DOI:10.1039/B903993G
Hg2+ is able to inhibit the peroxidase-like DNAzyme function of a T-containing G-quadruplex DNAviaHg2+-mediated T–T base pairs, which enables the visual detection of Hg2+ in the TMB–H2O2 reaction system with high selectivity and sensitivity.
Co-reporter:Li Shang and Shaojun Dong
Chemical Communications 2008(Issue 9) pp:NaN1090-1090
Publication Date(Web):2008/01/10
DOI:10.1039/B717728C
We report a new approach for the synthesis of fluorescent and water-soluble Ag nanoclusters, using the common polyelectrolyte poly(methacrylic acid) as the template.
Co-reporter:Lei Han, Chengzhou Zhu, Li Wang and Shaojun Dong
Catalysis Science & Technology (2011-Present) 2013 - vol. 3(Issue 6) pp:NaN1504-1504
Publication Date(Web):2013/04/03
DOI:10.1039/C3CY20653J
Chain-like CoCu hollow nanoparticles (CHNs) were facilely obtained via a one-pot synthesis process, and we found that the obtained CHNs exhibited high catalytic ability, excellent cycle stability and facile recovery towards the catalytic reduction of p-nitrophenol to p-aminophenol.
Co-reporter:Tao Li, Erkang Wang and Shaojun Dong
Chemical Communications 2008(Issue 43) pp:NaN5522-5522
Publication Date(Web):2008/09/23
DOI:10.1039/B809296F
With a designed high-activity DNAzyme as the catalytic label, an ultrasensitive chemiluminescence thrombin aptasensor is developed, enabling a 10- to 100-fold improvement in the detection sensitivity as compared with previous counterparts.
Co-reporter:Zhikun Xu, Lei Han, Peng Hu and Shaojun Dong
Catalysis Science & Technology (2011-Present) 2014 - vol. 4(Issue 10) pp:NaN3619-3619
Publication Date(Web):2014/07/29
DOI:10.1039/C4CY00889H
Uniform and small Ag@AgCl nanoparticles were for the first time prepared through a vapor diffusion strategy at room temperature. The size of the Ag@AgCl nanoparticles could be controlled by a diffuse vapor of HCl molecules with a slow rate and PVP used as a precursor. The smallest Ag@AgCl NPs exhibit excellent photocatalytic activity and stability.
Co-reporter:Yuling Wang, Hui Wei, Bingling Li, Wen Ren, Shaojun Guo, Shaojun Dong and Erkang Wang
Chemical Communications 2007(Issue 48) pp:NaN5222-5222
Publication Date(Web):2007/10/16
DOI:10.1039/B709492B
SERS aptasensors for protein recognition based on Au nanoparticles labeled with aptamers and Raman reporters have been developed, which opens a new way for protein recognition of high sensitivity and selectivity.
Co-reporter:Hui Wei, Bingling Li, Jing Li, Erkang Wang and Shaojun Dong
Chemical Communications 2007(Issue 36) pp:NaN3737-3737
Publication Date(Web):2007/06/29
DOI:10.1039/B707642H
We describe herein simple and sensitive aptamer-based colorimetric sensing of protein (alpha-thrombin in this work) using unmodified gold nanoparticle probes.
Co-reporter:Junfeng Zhai, Ling Liu, Daming Yong, Dan Li and Shaojun Dong
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 11) pp:NaN3854-3854
Publication Date(Web):2012/09/04
DOI:10.1039/C2AY25899D
In this work, we develop a reconfigured colorimetric bioassay for direct toxicity assessment (DTA) of toxic chemicals in water based on neutral red (NR) as a colorimetric indicator. Confocal laser scanning microscopy and UV-vis absorption spectroscopy are employed to prove the feasibility of the proposed assays using P. fluorescens as the model microorganism. The presence of toxicants can damage cells, and this results in an enhanced adsorption of NR by the cells. This fact provides a new strategy for DTA of toxic chemicals by comparing the absorption peak intensities of residual NR after incubation in the presence of toxicants. Four important toxicants such as 3,5-dichlorophenol (DCP), As3+, Hg2+ and Cr6+ are tested, and the toxicity order is DCP > Hg2+ > Cr6+ > As3+, which is identical with that obtained by the ferricyanide-mediated toxicity alerter (FM-tox) assay. The RC50 value of DCP is estimated to be 12.5 mg L−1, which is comparable with that of other DTA assays. The responses of E. coli and BOD seed (multi-species cultures) to DCP are further examined successfully, suggesting this NR based colorimetric assay may be a general one to measure the response of microorganisms to toxic chemicals. The low cost of NR, easy and simple operation procedure and reliable results make this assay a promising one in DTA.
Co-reporter:Libing Zhang, Jinbo Zhu, Zhixue Zhou, Shaojun Guo, Jing Li, Shaojun Dong and Erkang Wang
Chemical Science (2010-Present) 2013 - vol. 4(Issue 10) pp:NaN4010-4010
Publication Date(Web):2013/07/10
DOI:10.1039/C3SC51303C
Dynamic DNA assembly, operated in an autonomous and reconfigurable manner by controlling the kinetics of strand displacement reactions (SDR), is an ideal approach to amplify the fluorescent signals for molecular diagnostic and imaging. Herein, we for the first time have demonstrated an enhancement of fluorescence intensity of DNA/Ag nanocluster-based beacons by the modulation of SDR. This is a new DNA/Ag NCs fluorescence light-up system through the use of the enhancer of G-rich overhang. Such a sensing system can be used to develop a DNA/Ag nanocluster-based beacon for the fluorescent detection of nucleic acid and thrombin with high selectivity and sensitivity, in which the detection sensitivity could be further enhanced through additional Exo III based amplification.
Co-reporter:Shaojun Guo and Shaojun Dong
Chemical Society Reviews 2011 - vol. 40(Issue 5) pp:NaN2672-2672
Publication Date(Web):2011/01/31
DOI:10.1039/C0CS00079E
The emergence of graphene nanosheet (GN, 2010 Nobel Prize for Physics) has recently opened up an exciting new field in the science and technology of two-dimensional (2D) nanomaterials with continuously growing academic and technological impetus. GN exhibits unique electronic, optical, magnetic, thermal and mechanical properties arising from its strictly 2D structure and thus has many important technical applications. Actually, GN-based materials have enormous potential to rival or even surpass the performance of carbon nanotube-based counterparts, given that cheap, large-scale production and processing methods for high-quality GN become available. Therefore, the studies on GN in the aspects of chemistry, physical, materials, biology and interdisciplinary science have been in full flow in the past five years. In this critical review, from the viewpoint of chemistry and materials, we will cover recent significant advances in synthesis, molecular engineering, thin film, hybrids, and energy and analytical applications of the “star-material” GN together with discussion on its major challenges and opportunities for future GN research (315 references).
Co-reporter:Shu Jiang, Chengzhou Zhu and Shaojun Dong
Journal of Materials Chemistry A 2013 - vol. 1(Issue 11) pp:NaN3599-3599
Publication Date(Web):2013/01/18
DOI:10.1039/C3TA01682J
We demonstrated a facile method to synthesize nanosheet-like cobalt–nitrogen–graphene (Co–N–GN) composites acting as a highly active non precious metal-based catalyst for oxygen reduction reaction (ORR). Polypyrrole/graphene oxide (PPy/GO) nanocomposites were first synthesized via in situ polymerization at room temperature. Then, cobalt(II) nitrate was directly incorporated into the PPy/GO hybrids via annealing heat treatment to generate Co–N–GN composites. The as-synthesized Co–N–GN composites exhibited an extraordinary electrocatalytic performance towards ORR comparable to commercial Pt/C, for instance, high onset potential, superior methanol tolerance, and excellent stability in alkaline medium, making them the state-of-the-art non-precious metal ORR electrocatalysts for electrochemical energy applications.
Co-reporter:Lihua Jin, Youxing Fang, Peng Hu, Yanling Zhai, Erkang Wang and Shaojun Dong
Chemical Communications 2012 - vol. 48(Issue 15) pp:NaN2103-2103
Publication Date(Web):2012/01/13
DOI:10.1039/C2CC16523F
A novel inorganic–organic hybrid film structure based on polyoxometalate and conventional organic dye has been fabricated, whose fluorescence can be reversibly switched using the electrochromic component to activate or suppress the related fluorescence quenching mechanism upon applying reduction or oxidation potentials of polyoxometalates.
Co-reporter:Zhixue Zhou, Yaqing Liu and Shaojun Dong
Chemical Communications 2013 - vol. 49(Issue 30) pp:NaN3109-3109
Publication Date(Web):2013/02/27
DOI:10.1039/C3CC39272D
We present a unique, label-free and resettable molecular keypad lock that utilizes DNA-modulated Ag nanoclusters (Ag NCs) as signal responsers. The present work demonstrates the first example that exonuclease-catalyzed DNA hydrolysis reaction could be used to achieve the RESET function of a molecular keypad without complicated procedures.
Co-reporter:Lei Han, Zhikun Xu, Ping Wang and Shaojun Dong
Chemical Communications 2013 - vol. 49(Issue 43) pp:NaN4955-4955
Publication Date(Web):2013/04/08
DOI:10.1039/C3CC41798K
A novel and facile method is developed to prepare an Ag@AgCl film which exhibits high photocatalytic activity under visible light irradiation. In addition, it can also be used to fabricate a photodetector that possesses a fast response time and good photocurrent reproducibility.
Co-reporter:Li Wang, Chengzhou Zhu, Lei Han, Lihua Jin, Ming Zhou and Shaojun Dong
Chemical Communications 2011 - vol. 47(Issue 27) pp:NaN7796-7796
Publication Date(Web):2011/06/02
DOI:10.1039/C1CC11373A
Label-free, regenerative and sensitive surface plasmon resonance (SPR) and electrochemical aptasensors based on graphene for the detection of α-thrombin have been reported, which propose a new, simple way for protein recognition with high sensitivity and selectivity.
Co-reporter:Yueming Zhai, Lihua Jin, Ping Wang and Shaojun Dong
Chemical Communications 2011 - vol. 47(Issue 29) pp:NaN8270-8270
Publication Date(Web):2011/06/22
DOI:10.1039/C1CC13149D
We demonstrate for the first time that bifunctional Au–Fe3O4 dumbbell nanoparticles can be used for sensitive and selective turn-on fluorescent detection of cyanide based on the inner filter effect, and a “magnetic concentration–washing process” is proposed to effectively reduce the interference of dye pollution.
Co-reporter:Shaojun Guo, Shaojun Dong and Erkang Wang
Chemical Communications 2010 - vol. 46(Issue 11) pp:NaN1871-1871
Publication Date(Web):2010/01/13
DOI:10.1039/B922148D
We for the first time report a facile, wet-chemical strategy for the high-yield (∼100%) synthesis of ultralong Pt-on-Pd bimetallic nanowires (NWs) with the cores being Pd NWs and the shells being made of dendritic Pt, which exhibit high surface area and enhanced electrocatalytic activity towards methanol oxidation reaction.
Co-reporter:Lingling Zhang, Lei Han, Peng Hu, Li Wang and Shaojun Dong
Chemical Communications 2013 - vol. 49(Issue 89) pp:NaN10482-10482
Publication Date(Web):2013/09/10
DOI:10.1039/C3CC46163G
TiO2 nanotube arrays (NTA), prepared by potentiostatic anodization, were discovered to possess an intrinsic peroxidase-like activity. The colorimetric and electrochemical assays both demonstrated their excellent catalytic activity towards H2O2 reduction. On this basis, a simple and inexpensive electrochemical biosensor for glucose detection was developed.
Co-reporter:Tao Li, Erkang Wang and Shaojun Dong
Chemical Communications 2009(Issue 5) pp:NaN582-582
Publication Date(Web):2008/12/05
DOI:10.1039/B815814B
Two G-quadruplexDNAs are able to form peroxidase-like DNAzymes selectively promoted by K+, which provides a label-free approach to colorimetric detection of K+ with the highest sensitivity ever reported.
Co-reporter:Lei Han, Lu Bai, Chengzhou Zhu, Yizhe Wang and Shaojun Dong
Chemical Communications 2012 - vol. 48(Issue 49) pp:NaN6105-6105
Publication Date(Web):2012/04/30
DOI:10.1039/C2CC32168H
A new light-driven, membraneless and mediatorless glucose–air biofuel cell combining a TiO2 nanotube photoanode with an enzyme-modified biocathode has been successfully constructed. Upon UV light illumination, the open-circuit voltage and the maximum power density of the cell reach 1.00 V and 47 μW cm−2, respectively.
Co-reporter:Chengzhou Zhu, Junfeng Zhai and Shaojun Dong
Chemical Communications 2012 - vol. 48(Issue 75) pp:NaN9369-9369
Publication Date(Web):2012/06/19
DOI:10.1039/C2CC33844K
We demonstrated a facile and green approach to synthesize bifunctional fluorescent carbon nanodots via soy milk, which not only showed favorable photoluminescent properties, but also exhibited good electrocatalytic activity towards oxygen reduction reaction.
Co-reporter:Li Shang, Lihua Jin and Shaojun Dong
Chemical Communications 2009(Issue 21) pp:NaN3079-3079
Publication Date(Web):2009/04/14
DOI:10.1039/B902216C
We report a simple fluorescent method for sensitive cyanide detection based on the dissolution of Rhodamine B-adsorbed gold nanoparticles by cyanide.
Co-reporter:Liu Deng, Zhixue Zhou, Jing Li, Tao Li and Shaojun Dong
Chemical Communications 2011 - vol. 47(Issue 39) pp:NaN11067-11067
Publication Date(Web):2011/09/06
DOI:10.1039/C1CC14012D
Using the Hg2+-mediated T–T formation to strengthen the DNA duplexes and influence the configuration of fluorescent Ag NCs-forming sequences, a turn-on fluorescence detection method for Hg2+ has been established.
Co-reporter:Yuling Wang, Dan Li, Wen Ren, Zuojia Liu, Shaojun Dong and Erkang Wang
Chemical Communications 2008(Issue 22) pp:
Publication Date(Web):
DOI:10.1039/B801055B
Co-reporter:Tie Wang, Xiaoge Hu and Shaojun Dong
Chemical Communications 2007(Issue 18) pp:NaN1851-1851
Publication Date(Web):2007/02/13
DOI:10.1039/B616778K
Herein, we describe a simple and inexpensive method for forming superhydrophobic cloths with the highest water contact angle of close to 180°, in which normal commercial cloths serving as pristine materials are modified with suitable gold micro/nanostructures.
Co-reporter:Li Shang and Shaojun Dong
Journal of Materials Chemistry A 2008 - vol. 18(Issue 39) pp:NaN4640-4640
Publication Date(Web):2008/09/01
DOI:10.1039/B810409C
In this work, we report the first application of water-soluble fluorescent Ag nanoclusters in fluorescent sensors. The fluorescence of poly(methacrylic acid) (PMAA)-templated Ag nanoclusters was found to be quenched effectively by Cu2+, but not when other common metal ions were present. By virtue of the specific response toward the analyte, a new, simple, and sensitive fluorescent method for detecting Cu2+ has been developed based on Ag nanoclusters. The present assay allows for the sensing of Cu2+ in the range of 1.0 × 10−8 M to 6.0 × 10−6 M with a detection limit as low as 8 nM at a signal-to-noise ratio of 3. The quenching mechanism was discussed based on the absorption and fluorescence spectroscopy studies, which suggested that Cu2+ quenched the emission by binding with the free carboxylic groups of PMAA polymers that surround the emissive Ag nanoclusters. In addition, the response of Ag nanoclusters toward Cu2+ was found to be reversible, which further made the present system attractive for sensor applications. The present study shows a promising step toward the application of fluorescent metal nanoclusters, which may also serve as a foundation for the further design and understanding of these novel materials.
Co-reporter:Yueming Zhai, Junfeng Zhai, Ming Zhou and Shaojun Dong
Journal of Materials Chemistry A 2009 - vol. 19(Issue 38) pp:NaN7035-7035
Publication Date(Web):2009/08/14
DOI:10.1039/B912767D
In this paper, we have reported a facile method for the synthesis of ordered magnetic core–manganese oxide shell nanostructures. The process included two steps. First, manganese ferrite nanoparticles were obtained through a solvothermal method. Then, the manganese ferrite nanoparticles were mixed directly with KMnO4 solution without any additional modified procedures of the magnetic cores. It has been found that Mn element in the core can react with KMnO4 to form manganese oxide which acts as a seed for the in-situgrowth of manganese oxide shells. This is significant for the controllable fabrication of symmetrical ordered manganese oxide shell structures. The shell thickness can be easily controlled through the reaction time. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction and energy-dispersive X-ray spectroscopy have been employed to characterize the products at different reaction time. The magnetic materials can be used as absorbents in wastewater treatment and exhibit a strong capability to remove organic pollutants. Furthermore, the materials are superparamagnetic and exhibit relative high saturation magnetization at room temperature, which makes the separation procedure more convenient in wastewater treatment.
Co-reporter:Tie Wang, Xiaoge Hu and Shaojun Dong
Journal of Materials Chemistry A 2007 - vol. 17(Issue 39) pp:NaN4195-4195
Publication Date(Web):2007/08/06
DOI:10.1039/B707481F
Functionalized multiwalled carbon nanotubes (MWNTs) were selected as cross-linkers to construct three-dimensional (3D) porous nanoparticle/MWNT hybrid nanostructures by “bottom-up” self-assembly. The resultant 3D hybrid nanostructure was different from that of metal nanoparticle multilayer assemblies prepared by traditional routes using small molecules or polymers as cross-linkers. The rigidity of the MWNTs resulted in only partial coverage of the nanoparticle surfaces between the linkers during the growth of multilayer film, providing more accessible surfaces to allow target molecules to adsorb on to and react with. HRP was used as a simple model to study the porosity of this assembly.
Co-reporter:Peng Hu, Lei Han, Chengzhou Zhu and Shao Jun Dong
Chemical Communications 2013 - vol. 49(Issue 17) pp:NaN1707-1707
Publication Date(Web):2012/12/14
DOI:10.1039/C2CC37734A
We have constructed a colorimetric protein assay platform based on a nanoreactor. The novel strategy presents high sensitivity and excellent performance for the detection of thrombin. The linear range is 5.58 × 10−10 to 6.50 × 10−9 M and the detection limit down to 0.19 nM is achieved.
Co-reporter:Lei Han, Lu Bai and Shaojun Dong
Chemical Communications 2014 - vol. 50(Issue 7) pp:NaN804-804
Publication Date(Web):2013/10/24
DOI:10.1039/C3CC47080F
A novel self-powered ultraviolet (UV) photodetector was successfully constructed through combining Pt-modified TiO2 nanotubes and Prussian blue (PB)-modified ITO, in which the existence of UV could be judged easily by naked eye with the aid of PB for electrochromic display. More importantly, it could also self-recover without UV light illumination.
Co-reporter:Liu Deng, Ling Liu, Chengzhou Zhu, Dan Li and Shaojun Dong
Chemical Communications 2013 - vol. 49(Issue 25) pp:NaN2505-2505
Publication Date(Web):2013/02/07
DOI:10.1039/C3CC38776C
Hybrid AuNCs@SiO2@GQDs nanocomposites were synthesized via a multistep procedure; GQDs located near AuNCs showed enhanced fluorescent intensities and improved photostabilities. AuNCs@SiO2@GQDs nanocomposites allowed specific visualization of EGFR on cancer cells.
Co-reporter:Yan Du, Shaojun Guo, Haixia Qin, Shaojun Dong and Erkang Wang
Chemical Communications 2012 - vol. 48(Issue 6) pp:NaN801-801
Publication Date(Web):2011/11/03
DOI:10.1039/C1CC15303J
A new electrochemical label-free biosensor based on target-induced conjunction of a split aptamer as new chiral selector for oligopeptide using graphene–mesoporous silica–gold NP hybrids (GSGHs) as magnified sensing platform is firstly reported, which showed high sensitivity and selectivity for the detection of D-vasopressin (D-VP).
Co-reporter:Tao Li, Erkang Wang and Shaojun Dong
Chemical Communications 2008(Issue 31) pp:NaN3656-3656
Publication Date(Web):2008/06/09
DOI:10.1039/B805565C
Thrombin-binding aptamer is found to bind hemin to form a catalytic complex whose activity is significantly promoted by the addition of thrombin, which enables the colorimetric detection of thrombin with high specificity and sensitivity in a facile way.
Co-reporter:Yueming Zhai, Junfeng Zhai and Shaojun Dong
Chemical Communications 2010 - vol. 46(Issue 9) pp:NaN1502-1502
Publication Date(Web):2009/12/23
DOI:10.1039/B923466G
Chain-like and ring-like CoPt hollow nanoparticles were facilely obtained via a one-pot synthesis process, and we found that temperature played an important role in the assembly morphology.
Co-reporter:Liu Deng, Shaojun Guo, Zuojia Liu, Ming Zhou, Dan Li, Ling Liu, Gaiping Li, Erkang Wang and Shaojun Dong
Chemical Communications 2010 - vol. 46(Issue 38) pp:NaN7174-7174
Publication Date(Web):2010/08/18
DOI:10.1039/C0CC01371D
A significant increase (ca. 22-fold) in the electricity generation due to a Shewanella oneidensis MR-1 biofilm was observed in the presence of Fe3O4/Au nanocomposites.
Co-reporter:Bingling Li, Hui Wei and Shaojun Dong
Chemical Communications 2007(Issue 1) pp:NaN75-75
Publication Date(Web):2006/11/22
DOI:10.1039/B612080F
We report an aptamer-based method for the sensitive detection of proteins by a label-free fluorescing molecular switch (ethidium bromide), which shows promising potential in making protein assay simple and economical.
Co-reporter:Xiaoge Hu and Shaojun Dong
Journal of Materials Chemistry A 2008 - vol. 18(Issue 12) pp:NaN1295-1295
Publication Date(Web):2008/01/11
DOI:10.1039/B713255G
This review focuses on the synthesis, assembly, surface functionalization, as well as application of inorganic nanostructures. Electrochemical and wet-chemical methods are demonstrated to be effective approaches to make metal nanostructures under control without addition of a reducing agent or protecting agent. Owing to the unique physical and chemical properties of the nano-sized materials, novel applications are introduced using inorganic nanomaterials, such as electrocatalysis, photoelectricity, spectrochemistry, and analytical chemistry. This feature article provides detailed illustrations about the synthesis and assembly of metal nanostructures, surface modification of carbon nanotubes, as well as novel applications of inorganic nanomaterials, with an emphasis on metal nanostructures and carbon nanotubes derived from studies in the authors' laboratories.
Co-reporter:Bingling Li, Yan Du, Hui Wei and Shaojun Dong
Chemical Communications 2007(Issue 36) pp:NaN3782-3782
Publication Date(Web):2007/07/09
DOI:10.1039/B707057H
We report a sensitive electrochemical aptasensor for adenosine based on electrochemical impedance spectroscopy measurement, which gives not only a label-free but also a reusable platform to make the detection of small molecules simple and convenient.
Co-reporter:Chengzhou Zhu, Junfeng Zhai, Dan Wen and Shaojun Dong
Journal of Materials Chemistry A 2012 - vol. 22(Issue 13) pp:NaN6306-6306
Publication Date(Web):2012/02/21
DOI:10.1039/C2JM16699B
We introduce a facile method for the construction of graphene oxide/polypyrrole (GO/PPy) nanocomposites via one–step coelectrodeposition. In this process, the relatively large anionic GO serves as a weak electrolyte and is entrapped in the PPy nanocomposites during the electropolymerization of pyrrole, and also acts as an effective charge-balancing dopant within the PPy film. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) results demonstrate that the GO/PPy nanocomposites are successfully synthesized. The obtained GO/PPy nanocomposites exhibit good electrochemical properties and cycling performance, indicating a synergistic effect of PPy and GO. Taking its higher capacitance, lower cost and shorter processing time into consideration, GO may be a good choice for the fabrication of electrochemical supercapacitors based on conducting polymer nanocomposites. It should be noted that this coelectrodeposition is also applicable for the graphene oxide/poly[3,4-ethylenedioxythiophene] (GO/PEDOT) nanocomposites. Moreover, this facile and effective approach for the synthesis of GO/conducting polymer nanocomposites further extends the application of GO and should be very promising for the fabrication of inexpensive, high-performance electrochemical supercapacitors.
Co-reporter:Shaojun Guo and Shaojun Dong
Journal of Materials Chemistry A 2011 - vol. 21(Issue 42) pp:NaN16716-16716
Publication Date(Web):2011/07/12
DOI:10.1039/C1JM11382H
Metal nanomaterials (MNMs) have received considerable interest from different scientific communities due to their size, shape, composition and architecture-dependent chemical and physical properties. MNMs-based self-assembly techniques are often essential for creating new multi-dimensional assembly architectures, which are very important for revealing new or enhanced properties and application potentials. This feature article will focus on recent advances in MNMs-based self-assembly and their potential application in electrochemical sensor and surface enhanced Raman spectroscopy (SERS). First, new significant developments in different self-assembly strategies for constructing two-dimensional (2D) and three-dimensional (3D) MNMs-based arrays or superstructures will be summarized. Then, diversified assembling approaches to different types of hybrid or multifunctional nanomaterials containing MNMs will be outlined. The review next introduces some exciting new pushes for the use of nanoarchitectures produced through self-assembly techniques for applications in electrochemical sensors and SERS. Finally, we conclude with a look at the future challenges and prospects of the development of MNMs-based self-assembly.
Co-reporter:Zhikun Xu, Lei Han, Baohua Lou, Xiaowei Zhang and Shaojun Dong
Journal of Materials Chemistry A 2014 - vol. 2(Issue 14) pp:NaN2474-2474
Publication Date(Web):2014/01/10
DOI:10.1039/C3TC32400A
A series of photodetectors based on BiOBrxI(Cl)1−x films are fabricated via a facile and rapid interfacial self-assembly method. The photodetectors show a high signal to noise ratio, and the cutoff wavelength can be tuned over a broad range from the visible to the ultraviolet region simply by changing the composition of the BiOBrxI(Cl)1−x films.
Co-reporter:Chengzhou Zhu, Youxing Fang, Dan Wen and Shaojun Dong
Journal of Materials Chemistry A 2011 - vol. 21(Issue 42) pp:NaN16917-16917
Publication Date(Web):2011/07/15
DOI:10.1039/C1JM11612F
A one-step approach to synthesize functional two-dimensional graphene/SnO2 composite nanosheets (GSCN) is reported. It should be noted that SnCl2 is not only a reducing agent for graphene oxide (GO), but also a precursor of SnO2. On the other hand, polyelectrolyte poly(diallyldimethylammonium chloride) (PDDA) was introduced simultaneously in the preparation, to endow it with an ideal self-assembly building block. Through electrostatic interaction, a general method has been developed for the preparation of ternary GSCN/nanoparticles (GSCN/NPs) hybrid structures with high-density noble metal NPs. Prominent examples including Au, Pt and Au@Pt hybrid NPs could be loaded on the surface of GSCN. Furthermore, we employed high-density Au@Pt NPs supported on GSCN as the electrochemical material for nonenzymatic glucose detection, which exhibited good electrocatalytic activity.
![Ferrate(2-), [7,12-diethenyl-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoato(4-)-κN21,κN22,κN23,κN24]-, hydrogen (1:2), (SP-4-2)-](/data/chemimg/522800/14875-96-8.png)
![Ferrate(2-), [7,12-diethenyl-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoato(4-)-κN21,κN22,κN23,κN24]-, hydrogen (1:2), (SP-4-2)-](/data/chemimg/522800/14875-96-8_b.png)
![[1,1'-Biphenyl]-4,4'-diamine, 3,3',5,5'-tetramethyl-, sulfate (1:1)](http://img.cochemist.com/ccimg/54900/54827-18-8.png)
![[1,1'-Biphenyl]-4,4'-diamine, 3,3',5,5'-tetramethyl-, sulfate (1:1)](http://img.cochemist.com/ccimg/54900/54827-18-8_b.png)
