Co-reporter:Tianxiang Wei, Tingting Dong, Hong Xing, Ying Liu, and Zhihui Dai
Analytical Chemistry November 21, 2017 Volume 89(Issue 22) pp:12237-12237
Publication Date(Web):October 18, 2017
DOI:10.1021/acs.analchem.7b03068
To achieve high selectivity and sensitivity simultaneously in an electrochemical biosensing platform, cucurbituril and azide cofunctionalized graphene oxide, a new functional nanomaterial that acts as a go-between to connect the recognition element with amplified signal architecture, is developed in this work. The cucurbituril and azide cofunctionalized graphene oxide features a high specific surface area with abundant levels of the two types of functional groups. Specifically, it emerges as a powerful tool to link recognition elements with simplicity, high yield, rapidity, and highly selective reactivity through azide-alkynyl click chemistry. Moreover, it possesses many host molecules to interact with guest molecules (also signal molecules)-grafted branched ethylene imine polymer, through which the detection sensitivity can be greatly improved. Together with electro-click technology, a highly controllable, selective, and sensitive biosensing platform can be easily created. For VEGF165 protein detection, the electro-click assay has high selectivity and sensitivity; a dynamic detection range from 10 fg mL–1 to 1 ng mL–1 with a detection limit of 8 fg mL–1 was achieved. The electro-click biosensing strategy based on cucurbituril and azide cofunctionalized graphene oxide would have great promise for other target analytes with a broad range of applications.
Co-reporter:Junyao Li, Ling Si, Jianchun Bao, Zhaoyin Wang, and Zhihui Dai
Analytical Chemistry March 21, 2017 Volume 89(Issue 6) pp:3681-3681
Publication Date(Web):February 17, 2017
DOI:10.1021/acs.analchem.6b05112
The activity of alkaline phosphatase (ALP) is a crucial index of blood routine examinations, since the concentration of ALP is highly associated with various human diseases. To address the demands of clinical tests, efforts should be made to develop more approaches that can sense ALP in real samples. Recently, we find that fluorescence of poly(30T)-templated copper nanoparticles (CuNPs) can be directly and effectively quenched by pyrophosphate ion (PPi), providing new perspective in designing sensitive biosensors based on DNA-templated CuNPs. In addition, it has been confirmed that phosphate ion (Pi), product of PPi hydrolysis, does not affect the intense fluorescence of CuNPs. Since ALP can specifically hydrolyze PPi into Pi, fluorescence of CuNPs is thus regulated by an ALP-triggered reaction, and a novel ALP biosensor is successfully developed. As a result, ALP is sensitively and selectively quantified with a wide linear range of 6.0 × 10–2 U/L to 6.0 × 102 U/L and a low detection limit of 3.5 × 10–2 U/L. Besides, two typical inhibitors of ALP are evaluated by this analytical method, and different inhibitory effects are indicated. More importantly, by challenging this biosensor with real human serums, the obtained results get a fine match with the data from clinical tests, and the serum sample from a patient with liver disease is clearly distinguished, suggesting promising applications of this biosensor in clinical diagnosis.
Co-reporter:Zhaoyin Wang, Jian Zhao, Zijun Li, Jianchun Bao, and Zhihui Dai
Analytical Chemistry June 20, 2017 Volume 89(Issue 12) pp:6815-6815
Publication Date(Web):May 23, 2017
DOI:10.1021/acs.analchem.7b01238
Investigations on interaction between small molecules and DNA are the basis of designing advanced bioanalytical systems. We herein propose a novel interaction between heterocyclic aromatic compounds (HACs) and single-stranded DNA (ssDNA). Taking methylene blue (MB) as a typical HAC, it is found that MB can interact with cytosine (C)-rich ssDNA in an enthalpy-driven process. The interaction between MB and C-rich ssDNA is sequence and structure dual-dependent: at least three consecutive C and single-stranded structure are necessary, affecting the fluorescence response of metal nanoparticles. With the exception of the single-stranded structure, double-stranded, i-motif, and C–Ag–C mismatch structures will remarkably impede the interaction with MB. UV–vis absorption, fluorescent, and electrochemical curves demonstrate that the conjugated system, electron transition, and electron transfer of MB are remarkably affected by MB-C-rich ssDNA interaction. In particular, the absorption peak of MB at 664 nm decreases, and a new peak at 538 nm emerges. Therefore, the interaction can be characterized by a colorimetric and ratiometric signal. Relying on the inhibition of C–Ag–C mismatch and the enhanced analytical performances of the ratiometic signal, the MB-C-rich ssDNA interaction is further employed to quantify silver ions (Ag+) selectively and sensitively. In addition, since silver nanomaterials cannot introduce C–Ag–C mismatch, the fabricated biosensor is able to sense residual Ag+ in silver nanoparticles and silver nanowires, which is of great value in the precise and economical preparation of silver nanomaterials.
Co-reporter:Ruyan Li, Yue Zhang, Wenwen Tu, and Zhihui Dai
ACS Applied Materials & Interfaces July 12, 2017 Volume 9(Issue 27) pp:22289-22289
Publication Date(Web):June 16, 2017
DOI:10.1021/acsami.7b06107
By using in situ generation of electron acceptor coupled with heterojunction as dual signal amplification, a simple photoelectrochemical (PEC) bioanalysis platform was designed. The synergic effect between the photoelectrochemical (PEC) activities of carbon nitride (C3N4) nanosheets and PbS quantum dots (QDs) achieved almost nine-fold photocurrent intensity increment compared with the C3N4 alone. After the G-quadruplex/hemin/Pt nanoparticles (NPs) with catalase-like activity toward H2O2 were introduced, oxygen was in situ generated and acted as electron donor by improving charge separation efficiency and further enhancing photocurrent response. The dually amplified signal made enough sensitivity for monitoring H2O2 released from live cells. The photocathode was prepared by the stepwise assembly of C3N4 nanosheets and PbS QDs on indium tin oxide (ITO) electrode, which was characterized by scanning electron microscope. A signal-on protocol was achieved for H2O2 detection in vitro due to the relevance of photocurrent on the concentration of H2O2. Under the optimized condition, the fabricated PEC bioanalysis platform exhibited a linear range of 10–7000 μM with a detection limit of 1.05 μM at S/N of 3. Besides, the bioanalysis platform displayed good selectivity against other reductive biological species. By using HepG2 cells as a model, a dual signal amplifying PEC bioanalysis platform for monitoring cells was developed. The bioanalysis platform was successfully applied to the detection of H2O2 release from live cells, which provided a novel method for cells monitoring and would have prospect in clinical assay.Keywords: bioanalysis; cells monitoring; dual signal amplification; enzymatic catalysis; heterojunction; photoelectrochemical;
Co-reporter:Yu-Yun Chen;Yun Zhang;Xing Zhang;Tang Tang;Hao Luo;Shuai Niu;Zhi-Hui Dai;Li-Jun Wan;Jin-Song Hu
Advanced Materials 2017 Volume 29(Issue 39) pp:
Publication Date(Web):2017/10/01
DOI:10.1002/adma.201703311
AbstractA binder-free efficient MoNi4/MoO3-x nanorod array electrode with 3D open structure is developed by using Ni foam as both scaffold and Ni source to form NiMoO4 precursor, followed by subsequent annealing in a reduction atmosphere. It is discovered that the self-templated conversion of NiMoO4 into MoNi4 nanocrystals and MoO3-x as dual active components dramatically boosts the hydrogen evolution reaction (HER) performance. Benefiting from high intrinsic activity, high electrochemical surface area, 3D open network, and improved electron transport, the resulting MoNi4/MoO3-x electrode exhibits a remarkable HER activity with extremely low overpotentials of 17 mV at 10 mA cm−2 and 114 mV at 500 mA cm−2, as well as a superior durability in alkaline medium. The water–alkali electrolyzer using MoNi4/MoO3-x as cathode achieves stable overall water splitting with a small cell voltage of 1.6 V at 30 mA cm−2. These findings may inspire the exploration of cost-effective and efficient electrodes by in situ integrating multiple highly active components on 3D platform with open conductive network for practical hydrogen production.
Co-reporter:Jing Li;Hongbo Li
Analyst (1876-Present) 2017 vol. 142(Issue 12) pp:2177-2184
Publication Date(Web):2017/06/12
DOI:10.1039/C7AN00446J
A label-free photoelectrochemical (PEC) aptasensor for K+ was first constructed by direct self-assembly of the K+ aptamer onto the electrodeposited Mn-doped ZnO nanorods. In the presence of K+, the conformation of G-quadruplex changes to a K+-stabilized conformation, which can efficiently prevent the quercetin electron donor from reaching the functionalized photoanode, thus proportionately affecting the quercetin-enhanced photocurrent response. Under the optimal experimental conditions, the fabricated biosensor exhibited a linear response in the K+ concentration range of 0.012 to 12.32 nmol L−1, with a detection limit of 4.0 pmol L−1, which was 3–5 orders of magnitude lower than that of most of the recently reported methods. The presence of other ions did not interfere with the detection of K+, and the results in serum samples agreed well with those obtained by ICP-MS. Using K+ as the detection model, this novel PEC aptasensor exhibited a good performance in terms of ultrasensitivity, selectivity and simplicity, and it was economical. As regards the electrode modification, this work provided a convenient direct self-assembly strategy that did not require the use of ionic polymers such as PDDA as a binder. Thus, this study paves the way for the immobilization of molecular probes for label-free PEC aptasensing.
Co-reporter:Yuyun Chen;Yun Zhang;Yuling Ma;Tang Tang;Jinsong Hu;Lijun Wan
Chinese Journal of Chemistry 2017 Volume 35(Issue 6) pp:911-917
Publication Date(Web):2017/06/01
DOI:10.1002/cjoc.201600790
AbstractExploring facile and easily-scalable methods for synthesizing earth-abundant, cost-effective and efficient hydrogen evolution reaction (HER) electrocatalysts is essential for the mass production of hydrogen as a clean and sustainable energy carrier. We report here a simple strategy to produce Mo2C nanocrystals embedded in carbon network (Mo2C@C) by the direct pyrolysis of ammonium molybdate and polyvinylpyrrolidone (PVP). It is found that PVP can be effectively used as a single source to form carbides and carbon network. The long polymer chain and coordinating capability with transition metal of PVP make it possible to form connected porous carbon network and well-dispersed Mo2C nanocrystals in several nanometers. The carbonization of PVP not only effectively in-situ prevents the aggregation of Mo2C nanocrystals during their formation, but also provides conductive porous matrix. As a result, the Mo2C@C composite exhibits the superior electrocatalytic performance for HER, which can be ascribed to the large number of active sites from plenty of small Mo2C nanocrystals and the efficient mass and electron transport network from carbon matrix. This strategy may inspire the exploration of cost-effective functional polymer as single source for both carbon precursor and nanostructure-directed reagent to mass-produce well-defined metal carbides nanostructures embedded in porous carbon network for energy applications.
Co-reporter:Tianxiang Wei, Dan Du, Zhaoyin Wang, Weiwei Zhang, Yuehe Lin, Zhihui Dai
Biosensors and Bioelectronics 2017 Volume 94(Volume 94) pp:
Publication Date(Web):15 August 2017
DOI:10.1016/j.bios.2017.02.044
•A magnetic fluorescent miRNA sensing system was constructed.•miRNA can be detected rapidly and sensitively both in cell lysates and serum samples.•Au NPs functionalized MBs were newly prepared for rapid and efficient collection of target miRNA.•P19 protein-conjugated fluorescent Alb NPs were newly synthesized.MicroRNAs (miRNAs) play important roles in gene regulation and cancer development. Nowadays, it is still a challenge to detect low-abundance miRNAs. Here, we present a magnetic fluorescent miRNA sensing system for the rapid and sensitive detection of miRNAs from cell lysates and serum samples. In this system, albumin nanoparticles (Alb NPs) were prepared from inherent biocompatible bovine serum albumin (BSA). A large number of fluorescent dyes were loaded into Alb NPs to make Alb NPs serve as signal molecular nanocarriers for signal amplification. Benefited from the reactive functional groups-carboxyl groups of Alb NPs, p19 protein, a viral protein that can bind and sequester short RNA duplex effectively and selectively, was modified successfully to the surface of the fluorescent dyes-loaded Alb NPs, thus enabling the probe:target miRNA duplex recognition and binding. Followed by the introduction of gold nanoparticles coated magnetic microbeads (Au NPs-MBs), which were prepared through a novel and simple method, the system combined the merits of the rapid and efficient collection given by MBs with the good affinities to attach probe molecules endowed by the coated gold layer. A broad linear detection range of 10 fM–10 nM and a low detection limit of 9 fM were obtained within 100 min by detecting a model target miRNA-21. The feasibility of this method for rapid and sensitive quantification might advance the use of miRNAs as biomarkers in clinical praxis significantly.Download high-res image (445KB)Download full-size image
Co-reporter:Suli Liu; Qinghua Zhang; Long Zhang; Lin Gu; Guizheng Zou; Jianchun Bao
Journal of the American Chemical Society 2016 Volume 138(Issue 4) pp:1154-1157
Publication Date(Web):January 19, 2016
DOI:10.1021/jacs.5b12727
The research of highly active electrochemiluminescence (ECL) materials with low toxicity and good solubility remains a substantial challenge. In this work, we present a synthesis method to prepare soluble wurtzite (WZ) ZnSe nanocrystals (NCs), which exhibit good ECL properties. Using high-angle annular-dark-field imaging together with electron hologram methods, we observe that the WZ ZnSe NCs exhibit an unusual symmetry-breaking phenomenon, where the translational symmetry of the polarized Zn–Se bond is broken. The formation of a symmetry-breaking region leads to an accumulation of charge. The good ECL response originates from the increased efficiency of electron–hole recombination by the excess charge redistribution in WZ ZnSe NCs. This study of the relationship between ECL behavior and the architecture of NCs suggests that careful control over the NC structures of semiconductors can tailor their charge distribution via symmetry breaking, which opens new avenues for the design of novel classes of agents for optoelectronic applications.
Co-reporter:Yuliang Jiang, Zhaoyin Wang, and Zhihui Dai
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 6) pp:3644
Publication Date(Web):October 26, 2015
DOI:10.1021/acsami.5b08089
A novel nanocomposite, silicon–carbon-based dots@dopamine (Si-CDs@DA) was prepared using (3-aminopropyl) triethoxysilane, glycerol, and dopamine as raw materials via a rapid microwave-assisted irradiation. This type of Si-CDs@DA exhibited ultrabright fluorescence emission (quantum yield of 12.4%) and could response to Ag+ selectively and sensitively. Moreover, the obtained Si-CDs@DA can be further applied in sensing intracellular Ag+ and cell imaging, because of its photostability, salt stability, and low cytotoxicity. This study provides a simple and efficient approach for preparing novel Ag+ fluorescent probes, which could expand the application of carbon nanomaterials in designing related biosensors.Keywords: carbon-based dots; cell imaging; fluorescent probe; intracellular Ag+ sensing; Si-CDs@DA
Co-reporter:Zhaoyin Wang, Jian Zhao, Jianchun Bao, and Zhihui Dai
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 1) pp:827
Publication Date(Web):December 15, 2015
DOI:10.1021/acsami.5b10165
In this work, a new kind of peroxidase-mimicking DNAzyme (G-quadruplex-hemin DNAzyme, G4-hemin) was constructed by using hemin-modified G-rich DNA (hemin-G-DNA). Experimental results demonstrated that the G-rich DNA can form a G-quadruplex structure by the inducement of terminally modified hemin, rendering the assembly of hemin and G-quadruplex structure spontaneously and efficiently. As a result, G-hemin revealed higher peroxidase activity than traditional G-quadruplex/hemin DNAzyme (G4/hemin). Besides, different from G4/hemin, G4-hemin was constructed in one step without the participation of metal ions and adscititious hemin. Accordingly, the construction procedure was significantly simplified and the background signal from dissociative hemin was remarkably reduced. In a proof-of-concept trial, according to the colorimetric signals of G4-hemin, a novel biosensor for the detection of S1 nuclease activity was established, which provides a novel perspective for designing peroxidase-mimicking DNAzyme-based biosensors.Keywords: colorimetric biosensor; hemin-modified DNA; metal ion-free; peroxidase-mimicking DNAzyme; S1 nuclease
Co-reporter:Tianxiang Wei, Dan Du, Mei-Jun Zhu, Yuehe Lin, and Zhihui Dai
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 10) pp:6329
Publication Date(Web):February 19, 2016
DOI:10.1021/acsami.5b11834
Protein–inorganic nanoflowers, composed of protein and copper(II) phosphate (Cu3(PO4)2), have recently grabbed people’s attention. Because the synthetic method requires no organic solvent and because of the distinct hierarchical nanostructure, protein–inorganic nanoflowers display enhanced catalytic activity and stability and would be a promising tool in biocatalytical processes and biological and biomedical fields. In this work, we first coimmobilized the enzyme, antibody, and Cu3(PO4)2 into a three-in-one hybrid protein–inorganic nanoflower to enable it to possess dual functions: (1) the antibody portion retains the ability to specifically capture the corresponding antigen; (2) the nanoflower has enhanced enzymatic activity and stability to produce an amplified signal. The prepared antibody–enzyme–inorganic nanoflower was first applied in an enzyme-linked immunosorbent assay to serve as a novel enzyme-labeled antibody for Escherichia coli O157:H7 (E. coli O157:H7) determination. The detection limit is 60 CFU L–1, which is far superior to commercial ELISA systems. The three-in-one antibody (anti-E. coli O157:H7 antibody)–enzyme (horseradish peroxidase)–inorganic (Cu3(PO4)2) nanoflower has some advantages over commercial enzyme–antibody conjugates. First, it is much easier to prepare and does not need any complex covalent modification. Second, it has fairly high capture capability and catalytic activity because it is presented as aggregates of abundant antibodies and enzymes. Third, it has enhanced enzymatic stability compared to the free form of enzyme due to the unique hierarchical nanostructure.Keywords: E. coli O157:H7; ELISA; enzyme-labeled antibody; protein−inorganic nanoflower; ultrasensitive
Co-reporter:Yuanyuan Xu, Li Liu, Zhaoyin Wang, and Zhihui Dai
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 29) pp:18669-18674
Publication Date(Web):July 1, 2016
DOI:10.1021/acsami.6b01883
A stable and reusable electrochemical biosensor for the label-free detection of poly(ADP-ribose) polymerase (PARP) is designed in this work. C-kit-1, a thiol-modified G-quadruplex oligonucleotide, is first self-assembled on a gold electrode surface. The G-quadruplex structure of c-kit-1 can specifically tether and activate PARP, resulting in the generation of negatively charged poly(ADP-ribose) polymer (PAR). On the basis of electrostatic attraction, PAR facilitates the surface accumulation of positively charged electrochemical signal molecules. Through the characterization of electrochemical signal molecules, the label-free quantification of PARP is simply implemented. On the basis of the proposed method, selective quantification of PARP can be achieved over the linear range from 0.01 to 1 U with a calculated detection limit of 0.003U. Further studies also demonstrate the applicability of the proposed method to biosamples revealing the broad potential in practical applications. Furthermore, inhibitor of PARP has also been detected with this biosensor. Meanwhile, benefited from self-assembly on solid surface, this biosensor possesses two important features, i.e., reusability and stability, which are desirable in related biosensors.
Co-reporter:Wenwen Tu, Huijuan Cao, Long Zhang, Jianchun Bao, Xuhui Liu, and Zhihui Dai
Analytical Chemistry 2016 Volume 88(Issue 21) pp:10459
Publication Date(Web):October 10, 2016
DOI:10.1021/acs.analchem.6b02381
Using Au nanoparticles (NPs)-decorated, water-soluble, ZnSe-COOH nanoflakes (NFs), an ultrasensitive photoelectrochemical (PEC) biosensing strategy based on the dual signal amplification was proposed. As a result of the localized surface plasmon resonance (SPR) of Au NPs, the ultraviolet–visible absorption spectrum of Au NPs overlapped with emission spectrum of ZnSe-COOH NFs, which generated efficient resonant energy transfer (RET) between ZnSe-COOH NFs and Au NPs. The RET improved photoelectric conversion efficiency of ZnSe-COOH NFs and significantly amplified PEC signal. Taking advantage of the specificity and high affinity of p19 protein for 21–23 bp double-stranded RNA, p19 protein was introduced. P19 protein could generate remarkable steric hindrance, which blocked interfacial electron transfer and impeded the access of the ascorbic acid to electrode surface for scavenging holes. This led to the dramatic decrease of photocurrent intensity and the amplification of PEC signal change versus concentration change of target. Using microRNA (miRNA)-122a as a model analyte, an ultrasensitive signal-off PEC biosensor for miRNA detection was developed under 405 nm irradiation at −0.30 V. Owing to RET and remarkable steric hindrance of p19 protein as dual signal amplification, the proposed strategy exhibited a wide linear range from 350 fM to 5 nM, with a low detection limit of 153 fM. It has been successfully applied to analyze the level of miRNA-122a in HeLa cell, which would have promising prospects for early diagnosis of tumor.
Co-reporter:Xiaoying Wang, Li Liu, Zhaoyin Wang, Zhihui Dai
Journal of Electroanalytical Chemistry 2016 Volume 781() pp:351-355
Publication Date(Web):15 November 2016
DOI:10.1016/j.jelechem.2016.10.031
Graphene quantum dots (GQDs), an alternative of conventional luminescent reagents, has been widely used in electrochemiluminescent (ECL) analysis because of its low cost, non-toxicity and ease of preparation. To further improve the ECL signal of GQDs, we herein succeeded in synthesizing hydrazide modified graphene quantum dots (HM-SGQDs). In comparison with GQDs, HM-SGQDs possessed abundant luminol like units, thus greatly enhancing the ECL intensity. On the other hand, luminol involved ECL system typically needed the participation of H2O2 as a coreactant, while hemin/G-quadruplex DNAzyme (hGQ) DNAzyme could efficiently catalyze the decomposition of H2O2. Accordingly, taking p53 gene as a model, a novel ECL DNA biosensor was developed based on HM-SGQDs and hGQ DNAzyme. The experimental results indicated target DNA can be quantified in a linear range from 100 fM to 100 nM with a detection limit of 66 fM (S/N = 3). Meanwhile, the discrimination of single-base mismatch was also achieved with the proposed analytical approach, suggesting broad potential applications of nucleic acid-related clinical diagnosis.
Co-reporter:Ji-Sen Li, Hui-Qing Dong, Shun-Li Li, Run-Han Li, Zhi-Hui Dai, Jian-Chun Bao and Ya-Qian Lan
New Journal of Chemistry 2016 vol. 40(Issue 2) pp:914-918
Publication Date(Web):30 Jul 2015
DOI:10.1039/C5NJ01659B
A polyoxometalate (POM)-assisted fabrication of Pd nanoparticle/reduced graphene oxide (rGO) nanocomposite is reported. The hybrid exhibits enhanced catalytic activity and excellent methanol-tolerance capacity compared to its counterparts, due to the synergistic effect of Pd, POM, and rGO.
Co-reporter:Yuliang Jiang, Guo Wei, Wenjie Zhang, Ziyu Wang, Yixiang Cheng, Zhihui Dai
Sensors and Actuators B: Chemical 2016 Volume 234() pp:15-20
Publication Date(Web):29 October 2016
DOI:10.1016/j.snb.2016.04.124
In this study, carbon dots (CDs) were first obtained by using solid phase reaction method (SPRM). Compared with other methods, SPRM shows remarkable advantages on simple, rapid, and large scale CDs' fabrication without post-treatment and solvent-free. In addition, the obtained CDs can be employed as ideal fluorescent Fe3+ probe and fluorescent ink. By taking advantage of its low-cytotoxicity, the CDs can be further applied in cell imaging successfully. This strategy offers a simple and efficient approach for preparing CDs in large-scale and lays a foundation for its further multi-purpose application.
Co-reporter:Yu-Yun Chen, Yun Zhang, Wen-Jie Jiang, Xing Zhang, Zhihui Dai, Li-Jun Wan, and Jin-Song Hu
ACS Nano 2016 Volume 10(Issue 9) pp:8851
Publication Date(Web):September 12, 2016
DOI:10.1021/acsnano.6b04725
Well-defined pomegranate-like N,P-doped Mo2C@C nanospheres were prepared by simply using phosphomolybdic acid (PMo12) to initiate the polymerization of polypyrrole (PPy) and as a single source for Mo and P to produce N,P-doped Mo2C nanocrystals. The existence of PMo12 at the molecular scale in the polymer network allows the formation of pomegranate-like Mo2C@C nanospheres with a porous carbon shell as peel and Mo2C nanocrystals well-dispersed in the N-doped carbon matrix as seeds. This nanostructure provides several favorable features for hydrogen evolution application: (1) the conductive carbon shell and matrix effectively prevent the aggregation of Mo2C nanocrystals and facilitate electron transportation; (2) the uniform N,P-doping in the carbon shell/matrix and plenty of Mo2C nanocrystals provide abundant catalytically highly active sites; and (3) nanoporous structure allows the effective exposure of active sites and mass transfer. Moreover, the uniform distribution of P and Mo from the single source of PMo12 and N from PPy in the polymeric PPy–PMo12 precursor guarantees the uniform N- and P-co-doping in both the graphitic carbon matrix and Mo2C nanocrystals, which contributes to the enhancement of electrocatalytic performance. As a result, the pomegranate-like Mo2C@C nanospheres exhibit extraordinary electrocatalytic activity for the hydrogen evolution reaction (HER) in terms of an extremely low overpotential of 47 mV at 10 mA cm–2 in 1 M KOH, which is one of the best Mo-based HER catalysts. The strategy for preparing such nanostructures may open up opportunities for exploring low-cost high-performance electrocatalysts for various applications.Keywords: electrocatalysis; HER; molybdenum carbide; nanostructures; nanostructures
Co-reporter:Xia Liu
The Journal of Physical Chemistry C 2016 Volume 120(Issue 6) pp:3214-3220
Publication Date(Web):January 28, 2016
DOI:10.1021/acs.jpcc.5b11926
Antimony is a promising high-capacity anode material in sodium-ion batteries, but it generally shows poor cycling stability because of its large volume changes during sodium ion insertion and extraction processes. To alleviate or even overcome this problem, we develop a hybrid carbon encapsulation strategy to improve the anode performance of antimony through the combination of antimony/nitrogen-doped carbon (Sb/N-carbon) hybrid nanostructures and the carbon nanotube (CNT) network. When evaluated as an anode material for sodium-ion batteries, the as-synthesized Sb/N-carbon + CNT composite exhibits superior cycling stability and rate performance in comparison with Sb/N-carbon or Sb/CNT composite. A high charge capacity of 543 mA h g–1 with initial charge capacity retention of 87.7% is achieved after 200 cycles at a current density of 0.1 A g–1. Even under 10 A g–1, a reversible capacity of 258 mA h g–1 can be retained. The excellent sodium storage properties can be attributed to the formation of Sb–N bonding between the antimony nanoparticle and the nitrogen-doped carbon shell in addition to the electronically conductive and flexible CNT network. The hybrid carbon encapsulation strategy is simple yet very effective, and it also provides new avenues for designing advanced anode materials for sodium-ion batteries.
Co-reporter:Tianxiang Wei; Tingting Dong; Zhaoyin Wang; Jianchun Bao; Wenwen Tu
Journal of the American Chemical Society 2015 Volume 137(Issue 28) pp:8880-8883
Publication Date(Web):July 6, 2015
DOI:10.1021/jacs.5b04348
A novel concept is proposed for converting liquid-phase colorimetric assay into enhanced surface-tethered electrochemical analysis, which is based on the analyte-induced formation of a network architecture of metal nanoparticles (MNs). In a proof-of-concept trial, thymine-functionalized silver nanoparticle (Ag-T) is designed as the sensing unit for Hg2+ determination. Through a specific T-Hg2+-T coordination, the validation system based on functionalized sensing units not only can perform well in a colorimetric Hg2+ assay, but also can be developed into a more sensitive and stable electrochemical Hg2+ sensor. In electrochemical analysis, the simple principle of analyte-induced aggregation of MNs can be used as a dual signal amplification strategy for significantly improving the detection sensitivity. More importantly, those numerous and diverse colorimetric assays that rely on the target-induced aggregation of MNs can be augmented to satisfy the ambitious demands of sensitive analysis by converting them into electrochemical assays via this approach.
Co-reporter:Suli Liu; Qinghua Zhang; Yafei Li; Min Han; Lin Gu; Cewen Nan; Jianchun Bao
Journal of the American Chemical Society 2015 Volume 137(Issue 8) pp:2820-2823
Publication Date(Web):January 28, 2015
DOI:10.1021/ja5129154
The synthesis of highly active oxygen reduction reaction (ORR) catalysts with good durability and low cost is highly desirable but still remains a significant challenge. In this work, we present the synthesis of five-fold twinned Pd2NiAg nanocrystals (NCs) with a Ni-terminal surface which exhibit excellent electrocatalytic performance for ORR in alkaline media, even better than the performance of the commercial Pt/C catalyst. Using high-angle annular-dark-field imaging together with density functional theory calculations, it is found that the surfaces of the five-fold twinned Pd2NiAg NCs exhibit an unusual valence electron density. The maximum catalytic activity originates from the increased availability of surface Ni sites in five-fold twinned Pd2NiAg NCs and the features of twinned structural defects. This study provides an explanation of the enhanced ORR from the special structure of this novel material, which opens up new avenues for the design of novel classes of electrocatalysts for fuel cells and metal–air batteries.
Co-reporter:Zhaoyin Wang and Zhihui Dai
Nanoscale 2015 vol. 7(Issue 15) pp:6420-6431
Publication Date(Web):09 Mar 2015
DOI:10.1039/C5NR00585J
Carbon materials on the nanoscale exhibit diverse outstanding properties, rendering them extremely suitable for the fabrication of electrochemical biosensors. Over the past two decades, advances in this area have continuously emerged. In this review, we attempt to survey the recent developments of electrochemical biosensors based on six types of carbon nanomaterials (CNs), i.e., graphene, carbon nanotubes, carbon dots, carbon nanofibers, nanodiamonds and buckminsterfullerene. For each material, representative samples are introduced to expound the different roles of the CNs in electrochemical bioanalytical strategies. In addition, remaining challenges and perspectives for future developments are also briefly discussed.
Co-reporter:Shanshan Liu, Huijuan Cao, Zhaoyin Wang, Wenwen Tu and Zhihui Dai
Chemical Communications 2015 vol. 51(Issue 75) pp:14259-14262
Publication Date(Web):31 Jul 2015
DOI:10.1039/C5CC04092B
A universal and label-free photoelectrochemical cytosensing strategy was designed based on resonance energy transfer (RET) between carbon dots and cysteamine capped gold nanoparticles. RET promoted photo-to-current conversion efficiency and enhanced detection sensitivity. This proposed photoelectrochemical cytosensing platform exhibited a good performance for the assay of tumor cells with overexpressed receptors on cells.
Co-reporter:Ji-Sen Li, Shun-Li Li, Yu-Jia Tang, Min Han, Zhi-Hui Dai, Jian-Chun Bao and Ya-Qian Lan
Chemical Communications 2015 vol. 51(Issue 13) pp:2710-2713
Publication Date(Web):05 Jan 2015
DOI:10.1039/C4CC09062D
A novel nitrogen-doped Fe/Fe3C@graphitic layer/carbon nanotube hybrid derived from MOFs has been first fabricated by a facile approach. The hybrid exhibited outstanding bifunctional electrocatalytic activity for ORR and OER, due to the merits of graphitic layer/carbon nanotube structures with highly active N and Fe/Fe3C sites.
Co-reporter:Yulin Zheng, Shulin Zhao, Suli Liu, Huanhuan Yin, Yu-Yun Chen, Jianchun Bao, Min Han, and Zhihui Dai
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 9) pp:5347
Publication Date(Web):February 19, 2015
DOI:10.1021/acsami.5b01541
Exploring low-cost, high-activity, and long-durability hybrid electrocatalysts for cathodic oxygen reduction reaction (ORR) is vital to advance fuel cells technologies. In this paper, a series of graphene (G)–CuxPdy (Cu4Pd, Cu3Pd, CuPd, CuPd3, CuPd4) nanocomposites (G–CuxPdy NCPs) is obtained by assembly of CuxPdy alloy nanocrystals (NCs) with controlled component ratios on G nanosheets using the “dispersing–mixing–vaporizing solvent” strategy and used as electrocatalysts for ORR. Compared with pure CuxPdy NCs, greatly enhanced interfacial electron transfer dynamics are observed in G–CuxPdy NCPs, which show a strong correlation with the alloy compositions of the NCPs. The electrocatalytic experiments in alkaline solution reveal that the ORR activities of those G–CuxPdy NCPs are also strongly dependent on alloy components and exhibit a double-volcano feature with variations of alloy components. Among them, G–Cu3Pd NCPs possess the highest electrocatalytic activity, which is much better than some reported electrocatalysts and commercial Pd/C catalyst and close to Pt/C catalyst. By correlating the Pd 3d binding energies and the sizes of CuxPdy NCs with the mass-specific activities of G–CuxPdy NCPs and considering the interfacial electron transfer dynamics, the best catalytic activity of G–Cu3Pd NCPs may result from the unique electronic structure and the smallest size of Cu3Pd NCs as well as the strong synergistic effect between G and Cu3Pd NCs. Moreover, the durability of G–Cu3Pd NCPs is superior to that of Pt/C catalyst, indicating that they are promising cathodic electrocatalysts for using in alkaline fuel cells.Keywords: assembly; bimetallic nanocrystals; electrocatalysis; graphene; nanocomposites; oxygen reduction reaction
Co-reporter:Jing Lou, Zhaoyin Wang, Xiao Wang, Jianchun Bao, Wenwen Tu and Zhihui Dai
Chemical Communications 2015 vol. 51(Issue 78) pp:14578-14581
Publication Date(Web):11 Aug 2015
DOI:10.1039/C5CC06156C
A “signal-on” electrochemiluminescent DNA biosensing platform was proposed based on the dual quenching and strand displacement reaction. This novel “signal-on” detection strategy revealed its sensitivity in achieving a detection limit of 2.4 aM and its selectivity in distinguishing single nucleotide polymorphism of target DNA.
Co-reporter:Yuyun Chen, Min Han, Yujia Tang, Jianchun Bao, Shunli Li, Yaqian Lan and Zhihui Dai
Chemical Communications 2015 vol. 51(Issue 62) pp:12377-12380
Publication Date(Web):23 Jun 2015
DOI:10.1039/C5CC02717A
Novel polypyrrole–polyoxometalate/reduced graphene oxide ternary nanohybrids (TNHs) are synthesized via a one-pot redox relay strategy. The TNHs exhibit high areal specific capacitance (2.61 mF cm−2), and the fabricated solid device also exhibits good rate capability, excellent flexibility and mechanical stability.
Co-reporter:Ling Yuan, Wenwen Tu, Jianchun Bao, and Zhihui Dai
Analytical Chemistry 2015 Volume 87(Issue 1) pp:686
Publication Date(Web):December 10, 2014
DOI:10.1021/ac5034903
On the basis of a DNAzyme and a restriction-endonuclease-assisted target recycling strategy using Pd–Au alloy nanocrystals to immobilize probe DNA on an electrode and catalyze the reduction of H2O2 which amplified signal and promoted the detection sensitivity, a versatile biosensing platform for DNA detection was proposed. Using p53 and oral cancer genes as models, hemin/G-quadruplex simultaneously acted as a reduced nicotinamide adenine dinucleotide (NADH) oxidase and a horseradish peroxidase (HRP)-mimicking DNAzyme, and a versatile DNA biosensor was designed for the first time based on the good electrocatalytic activity of Pd–Au alloy nanocrystals. Hemin/G-quadruplex catalyzed the reduction of H2O2, which was generated from NADH in the presence of O2, to produce an electrochemical signal when thionine functioned as the electron mediator. Moreover, the nicking endonuclease N.BstNB I caused the target DNA to cycle for multiple rounds and further amplified the electrochemical response. This versatile DNA biosensor exhibited linear ranges for the detection of p53 and oral cancer genes from 0.1 fmol L–1 to 0.1 nmol L–1 and 0.1 fmol L–1 to 1 nmol L–1, respectively. The detection limits, established as 3σ, were estimated to be 0.03 and 0.06 fmol L–1 for the p53 and oral cancer genes, respectively. The as-prepared biosensor could discriminate mismatched sequences, indicating a satisfactory selectivity and validating the feasibility of the proposed strategy. More importantly, simply by changing the helper DNA, this versatile DNA biosensor could detect different target DNA species, which could create a new avenue for the potential diagnosis of cancer.
Co-reporter:Jing Lou, Shanshan Liu, Wenwen Tu, and Zhihui Dai
Analytical Chemistry 2015 Volume 87(Issue 2) pp:1145
Publication Date(Web):December 19, 2014
DOI:10.1021/ac5037318
A novel strategy for highly sensitive electrochemiluminescence (ECL) detection of DNA was proposed based on site-specific cleavage of BamHI endonuclease combined with the excellent ECL activity of graphene quantum dots (GQDs) and bidentate chelation of the dithiocarbamate DNA (DTC-DNA) probe assembly. The difference between photoluminescence and ECL spectral peaks suggested that a negligible defect existed on the GQDs surface for generation of an ECL signal. The formed DTC-DNA was directly attached to the gold surface by bidentate anchoring (S–Au–S bonds), which conferred a strong affinity between the ligands and the gold surface, increasing the robustness of DNA immobilization on the gold surface. BamHI endonuclease site-specifically recognized and cleaved the duplex symmetrical sequence, which made the double-stranded DNA fragments and GQDs break off from the electrode surface, inducing a decrease of the ECL signal. Using hepatitis C virus-1b genotype complementary DNA (HCV-1b cDNA) as a model, a novel signal-off ECL DNA biosensor was developed based on variation of the ECL intensity before and after digestion of the DNA hybrid. Electrochemical impedance spectroscopy confirmed the successful fabrication of the ECL DNA biosensor. This ECL biosensor for HCV-1b cDNA determination exhibited a linear range from 5 fM to 100 pM with a detection limit of 0.45 fM at a signal-to-noise ratio of 3 and showed satisfactory selectivity and good stability, which validated the feasibility of the designed strategy. The proposed strategy may be conveniently combined with other specific biological recognition events for expansion of the biosensing application, especially in clinical diagnoses.
Co-reporter:Can Zhang, Jing Lou, Wenwen Tu, Jianchun Bao and Zhihui Dai
Analyst 2015 vol. 140(Issue 2) pp:506-511
Publication Date(Web):29 Oct 2014
DOI:10.1039/C4AN01284D
A universal and sensitive electrochemical biosensing platform for the detection and identification of DNA using CdSe quantum dots (CdSe QDs) as signal markers was designed. The detection mechanism was based on the specific recognition of MspI endonuclease combined with the signal amplification of gold nanoparticles (AuNPs). MspI endonuclease could recognize its specific sequence in the double-strand DNA (dsDNA) and cleave the dsDNA fragments linked with CdSe QDs from the electrode. The remaining attached CdSe QDs can be easily read out by square-wave voltammetry using an electrodeposited bismuth (Bi) film-modified glass carbon electrode. The concentrations of target DNA could be simultaneously detected by the signal of metal markers. Using mycobacterium tuberculosis (Mtb) DNA as a model, under the optimal conditions, the proposed biosensor could detect Mtb DNA down to 8.7 × 10−15 M with a linear range of 5 orders of magnitude (from 1.0 × 10−14 to 1.0 × 10−9 M) and discriminate mismatched DNA with high selectivity. This strategy presented a universal and convenient biosensing platform for DNA assay, and its satisfactory performances make it a potential candidate for the early diagnosis of gene-related diseases.
Co-reporter:Ji-Sen Li, Yu-Jia Tang, Shun-Li Li, Shu-Ran Zhang, Zhi-Hui Dai, Ling Si and Ya-Qian Lan
CrystEngComm 2015 vol. 17(Issue 5) pp:1080-1085
Publication Date(Web):24 Nov 2014
DOI:10.1039/C4CE02020K
Metal–organic frameworks (MOFs) hybrid composites, combining the advantages of both MOFs and nanoparticles, may exhibit unprecedented properties. Herein, carbon nanodots (Cdots) functional UMCM-1 composites (Cdots@UMCM-1a) were successfully synthesized by a stepwise synthetic approach for the first time. The hybrids retain the intact structure of MOFs with high luminescence and longer stability. Due to the interactions between polar functional groups at the surface of the Cdots and H2 molecules, Cdots@UMCM-1a efficiently enhanced H2 storage capacity. Most importantly, Cdots@UMCM-1a exhibited highly fluorescent sensing for nitroaromatic explosives owing to the double effect of porous MOFs and fluorescent Cdots. This work will pave new avenues for the fabrication of novel and multifunctional MOFs composites.
Co-reporter:Long Zhang;Shulin Zhao;Yafei Li;Yaqian Lan;Min Han;Jianchun Bao
European Journal of Inorganic Chemistry 2015 Volume 2015( Issue 13) pp:2229-2236
Publication Date(Web):
DOI:10.1002/ejic.201500008
Abstract
We have developed a simple and facile approach to the fabrication of monoclinic Cu2Se nanocrystals and Cu2Se/Pd heterostructures. [(C2H5)4N]2[CuCl4] was chosen as the copper source and SeO2/terpineol was used as the Se–II precursor for the generation of hexagonal CuSe and cubic Cu2–xSe through the “hot-injection” and “one-pot” methods, respectively. Both CuSe and Cu2–xSe could be further transformed into monoclinic Cu2Se through heat treatment with trioctylphosphine (TOP) at 220 °C. Cu2Se/Pd as well as CuSe/Pd and Cu2–xSe/Pd were readily obtained by simply mixing copper selenides and Pd(NO3)2 in a 2-propanol solution. The Pd nanoparticles were distributed on the surface of the copper selenides. The effect of certain reaction parameters on the formation of copper selenides was studied. The amount of terpineol used played an important role in the phase-selective synthesis of CuSe and Cu2–xSe. The surface-enhanced Raman scattering (SERS) performance of the heterostructures was investigated with 4-mercaptopyridine (4-Mpy) as a probe molecule. Owing to the strong synergistic effects between Cu2Se and Pd, Cu2Se/Pd showed greater SERS performance than pure Pd or Cu2Se. Moreover, compared to those of CuSe/Pd and Cu2–xSe/Pd, Cu2Se/Pd exhibited the highest SERS sensitivity to 4-Mpy with a detection limit as low as 1.0 × 10–9 M, which revealed its phase- and composition-dependent characteristics. This Cu2Se/Pd heterostructure exhibits potential applications in the chemical and biological sensing fields.
Co-reporter:Suli Liu, Tianxiang Wei, Qian Liu, Wenwen Tu, Yaqian Lan, Min Han, Jianchun Bao and Zhihui Dai
Analytical Methods 2015 vol. 7(Issue 8) pp:3466-3471
Publication Date(Web):23 Mar 2015
DOI:10.1039/C4AY01857E
We develop a novel strategy for the biosensing application of hydrogen peroxide (H2O2) using nanoscaled Au–horseradish peroxidase (HRP) composite thin film synthesized by a liquid–liquid interface reaction. Through the interaction between Au nanoparticles and NH2-terminated HRP, HRP is effectively combined with Au in the thin film. The nanocomposite membrane is extracted on the surface of the ITO electrode directly, retaining its bioactivity during the immobilization process, which can detect the substrate in situ. The immobilized HRP displays an excellent electrocatalytic response to the reduction of H2O2, with a fast amperometric response (within 5 s), wide linear range (7.9 μM to 3.6 mM), low detection limit (0.035 μM), and a good affinity (Kappm = 0.14 mM) to H2O2. The prepared biosensor also exhibits high sensitivity, good reproducibility and long-term stability. Furthermore, it can be successfully exploited for the determination of H2O2 released from living cells directly adhered on the modified electrode surface.
Co-reporter:Xia Liu
The Journal of Physical Chemistry C 2015 Volume 119(Issue 11) pp:5848-5854
Publication Date(Web):March 3, 2015
DOI:10.1021/jp512152f
Silicon-based lithium-ion battery anodes have brought encouraging results to the current state-of-the-art battery technologies due to their high theoretical capacity, but their large-scale application has been hampered by a large volume change (>300%) of silicon upon lithium insertion and extraction, which leads to severe electrode pulverization and capacity degradation. Polymeric surfactants directing the combination of silicon nanoparticles and reduced graphene oxide have attracted great interest as promising choices for accommodating the huge volume variation of silicon. However, the influence of different polymeric surfactants on improving the electrochemical performance of silicon/reduced graphene oxide (Si/RGO) anodes remains unclear because of the different structural configurations of polymeric surfactants. Here, we systematically study the effect of different polymeric surfactants on enhancing the Si/RGO anode performance. Three of the most well-known polymeric surfactants, poly(sodium 4-styrenesulfonate) (PSS), poly(diallydimethylammonium chloride) (PDDA), and polyvinylpyrrolidone (PVP), were used to direct the combination of silicon nanoparticles and RGO through van der Waals interaction. The Si/RGO anodes made from these composites act as ideal models to investigate and compare how the van der Waals forces between polymeric surfactants and GO affect the final silicon anode performance from both experimental observations and theoretical simulations. We found that the capability of these three surfactants in enhancing long-term cycling stability and high-rate performance of the Si/RGO anodes decreased in the order of PVP > PDDA > PSS.
Co-reporter:Pengzi Wang
The Journal of Physical Chemistry C 2015 Volume 119(Issue 37) pp:21336-21344
Publication Date(Web):September 1, 2015
DOI:10.1021/acs.jpcc.5b05443
In contrast to the extensive investigation of the electrochemical performance of conventional carbon materials in sodium-ion batteries, there has been scarcely any study of sodium storage property of fluorine-doped carbon. Here we report for the first time the application of fluorine-doped carbon particles (F-CP) synthesized through pyrolysis of lotus petioles as anode materials for sodium-ion batteries. Electrochemical tests demonstrate that the F-CP electrode delivers an initial charge capacity of 230 mA h g–1 at a current density of 50 mA g–1 between 0.001 and 2.8 V, which greatly outperforms the corresponding value of 149 mA h g–1 for the counterpart banana peels-derived carbon (BPC). Even under 200 mA g–1, the F-CP electrode could still exhibit a charge capacity of 228 mA h g–1 with initial charge capacity retention of 99.1% after 200 cycles compared to the BPC electrode with 107 mA h g–1 and 71.8%. The F-doping and the large interlayer distance as well as the disorder structure contribute to a lowering of the sodium ion insertion–extraction barrier, thus promoting the Na+ diffusion and providing more active sites for Na+ storage. In specific, the F-CP electrode shows longer low-discharge-plateau and better kinetics than does the common carbon-based electrode. The unique electrochemical performance of F-CP enriches the existing knowledge of the carbon-based electrode materials and broadens avenues for rational design of anode materials in sodium-ion batteries.
Co-reporter:Yunxia Liu
The Journal of Physical Chemistry C 2015 Volume 119(Issue 49) pp:27316-27321
Publication Date(Web):November 16, 2015
DOI:10.1021/acs.jpcc.5b09553
Although lithium–selenium batteries have attracted significant attention for high-energy-density energy storage systems due to their high volumetric capacity, their implementation has been hampered by the dissolution of polyselenide intermediates into electrolyte. Herein, we report a novel selenium/microporous carbon nanofiber composite as a high-performance cathode for lithium–selenium batteries through binding selenium in microporous carbon nanofibers. Under vacuum and heat treatment, selenium particles are easily transformed into chainlike Sen molecules that chemically bond with the inner surfaces of microporous carbon nanofibers. This chemical bonding can not only promote robust and intimate contact between selenium and carbonaceous nanofiber matrix but also alleviate the active material dissolution during cycling. Moreover, selenium is homogeneously distributed in the micropores of the highly conductive carbonaceous nanofiber matrix, which is favorable for the fast diffusions of both lithium ions and electrons. As a result, a high reversible capacity of 581 mA h g–1 in the first cycle at 0.1 C and over 400 mA h g–1 after 2000 cycles at 1 C with excellent cyclability and high rate performance (over 420 mA h g–1 at 5 C, 3.39 A g–1) are achieved with the selenium/microporous carbon nanofibers composite as a cathode for lithium–selenium batteries, performing among the best of current selenium–carbon cathodes. This simple preparation method and strongly coupling hybrid nanostructure can be extended to other selenium-based alloy cathode materials for lithium–selenium batteries.
Co-reporter:Suli Liu, Jinxing Zhang, Wenwen Tu, Jianchun Bao and Zhihui Dai
Nanoscale 2014 vol. 6(Issue 4) pp:2419-2425
Publication Date(Web):05 Dec 2013
DOI:10.1039/C3NR05944H
Using ruthenium polypyridyl functionalized ZnO mesocrystals as bionanolabels, a universal biological recognition and biosensing platform based on gold nanoparticle (AuNP) dotted reduced graphene oxide (rGO) composite was developed. AuNP–rGO accelerated electron transfer between the detection probe and the electrode, and increased the surface area of the working electrode to load greater amounts of the capture antibodies. The large surface area of ZnO mesocrystals was beneficial for loading a high content ruthenium polypyridyl complex, leading to an enhanced electrochemiluminescence signal. Using α-fetoprotein (AFP) as a model, a simple and sensitive sandwich-type electrochemiluminescence biosensor with tripropylamine (TPrA) as a coreactant for detection of AFP was constructed. The designed biosensor provided a good linear range from 0.04 to 500 ng mL−1 with a low detection limit of 0.031 ng mL−1 at a S/N of 3 for AFP determination. The proposed biological recognition and biosensing platform extended the application of ruthenium polypyridyl functionalized ZnO mesocrystals, which provided a new promising prospect.
Co-reporter:Yunxia Liu, Ling Si, Xiaosi Zhou, Xia Liu, Yan Xu, Jianchun Bao and Zhihui Dai
Journal of Materials Chemistry A 2014 vol. 2(Issue 42) pp:17735-17739
Publication Date(Web):11 Sep 2014
DOI:10.1039/C4TA03141E
A novel selenium–carbon composite has been fabricated by embedding selenium in metal–organic framework-derived microporous carbon polyhedra. Such interconnected microporous carbon polyhedra possess a large surface area and pore volume to effectively confine Se, and suppress the dissolution of polyselenides in the electrolyte. This selenium–carbon composite shows ultrastable cycling performance when used as a cathode material for lithium–selenium batteries.
Co-reporter:Jisen Li, Yuyun Chen, Yujia Tang, Shunli Li, Huiqing Dong, Kui Li, Min Han, Ya-Qian Lan, Jianchun Bao and Zhihui Dai
Journal of Materials Chemistry A 2014 vol. 2(Issue 18) pp:6316-6319
Publication Date(Web):29 Jan 2014
DOI:10.1039/C3TA15335E
A novel MOF-templated nitrogen and sulphur co-doped porous material has been synthesized as an efficient electrocatalyst for oxygen reduction reactions (ORRs) for the first time. The representative NS(3:1)–C-MOF-5 catalyst shows the highest onset potential, and is even comparable to commercial Pt–C catalyst, due to the synergistic effect of N and S co-doping.
Co-reporter:Huanhuan Yin, Suli Liu, Chunli Zhang, Jianchun Bao, Yulin Zheng, Min Han, and Zhihui Dai
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 3) pp:2086
Publication Date(Web):January 6, 2014
DOI:10.1021/am405164f
In this paper, a series of well-coupled graphene (G) and MPd3 (M = Fe, Cu, Ag, Au, Cr, Mo, W) nanocrystals nanocomposites (G-MPd3 NCPs) have been synthesized via a versatile electrostatic assembly and hydrogen reduction strategy, i.e., sequential assembly of coordination anions and cations on excess cationic polymer modified graphene oxide to form composite precursors and then thermal treating under H2/Ar gases atmosphere. In those NCPs, the MPd3 components are uniform and smaller than 10 nm, which are well anchored on G with “naked” or “clean” surfaces. By adjusting reaction temperature, the interplay of MPd3 nanocrystals and G can be well-controlled. Below 700 °C, no sintering phenomena are observed, indicating the unprecedented dispersion and stability effect of G for MPd3 nanocrystals. All the obtained NCPs can be directly used to catalyze oxygen reduction reaction in alkaline media. Compared with single component, monometallic, and some reported non-Pt catalysts, greatly enhanced electrocatalytic performances are observed in those NCPs due to strong synergistic or coupling of their constituents. Among them, G-FePd3 NCPs exhibit the highest catalytic activity, but their current density needs to be improved compared with G-CrPd3, G-MoPd3, and G-WPd3 ones. This work not only provides a general strategy for fabricating well-coupled G-MPd3 NCPs but also paves the way for future designing multicomponent NCPs with multiple interfaces to apply in alkaline fuel cells.Keywords: bimetallic nanocrystals; electrocatalysis; electrostatic assembly; graphene; hydrogen reduction; nanocomposites;
Co-reporter:Jing Li, Wenwen Tu, Hongbo Li, Jianchun Bao and Zhihui Dai
Chemical Communications 2014 vol. 50(Issue 17) pp:2108-2110
Publication Date(Web):02 Jan 2014
DOI:10.1039/C3CC49109A
A robust aptasensor for Ag+ was proposed for the first time using an enhanced ZnO nanorod-based photoelectrochemistry by in situ generated AgBr via layer-by-layer assembly. This work opens up new avenues for application of one-dimensional ZnO nanorod arrays in photoelectrochemical sensing. Additionally, the strategy of employing in situ generated narrow-bandgap semiconductors paves a new way for photoelectrochemical sensing.
Co-reporter:Tianxiang Wei, Yuyun Chen, Wenwen Tu, Yaqian Lan and Zhihui Dai
Chemical Communications 2014 vol. 50(Issue 66) pp:9357-9360
Publication Date(Web):26 Jun 2014
DOI:10.1039/C4CC03555K
A versatile label-free, stable, low-cost and simple electrochemical biosensing platform has been developed based on a phosphomolybdic acid anion probe by jointly taking advantages of its native electronegativity, electrochemical activity and chemisorption with graphene oxide.
Co-reporter:Xianxiang Zeng, Wenwen Tu, Jing Li, Jianchun Bao, and Zhihui Dai
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 18) pp:16197
Publication Date(Web):August 25, 2014
DOI:10.1021/am5043164
An innovative photoelectrochemical (PEC) biosensor platform was designed based on the in situ generation of CdS quantum dots (QDs) on graphene oxide (GO) using an enzymatic reaction. Horseradish peroxidase catalyzed the reduction of sodium thiosulfate with hydrogen peroxide to generate H2S, which reacted with Cd2+ to form CdS QDs. CdS QDs could be photoexcited to generate an elevated photocurrent as a readout signal. This strategy offered a “green” alternative to inconvenient presynthesis procedures for the fabrication of semiconducting nanoparticles. The nanomaterials and assembly procedures were characterized by microscopy and spectroscopy techniques. Combined with immune recognition and on the basis of the PEC activity of CdS QDs on GO, the strategy was successfully applied to a PEC assay to detect carcinoembryonic antigen and displayed a wide linear range from 2.5 ng mL–1 to 50 μg mL–1 and a detection limit of 0.72 ng mL–1 at a signal-to-noise ratio of 3. The PEC biosensor showed satisfactory performance for clinical sample detection and was convenient for determining high concentrations of solute without dilution. This effort offers a new opportunity for the development of numerous rapid and convenient analytical techniques using the PEC method that may be applied in the design and preparation of various solar-energy-driven applications.Keywords: biosensing; enzyme catalysis; graphene oxide; photoelectrochemistry; quantum dots
Co-reporter:Jing Li, Wenwen Tu, Hongbo Li, Min Han, Yaqian Lan, Zhihui Dai, and Jianchun Bao
Analytical Chemistry 2014 Volume 86(Issue 2) pp:1306
Publication Date(Web):December 30, 2013
DOI:10.1021/ac404121c
A novel in situ-generated nanogold plasmon-enhanced photoelectrochemical aptasensor for Hg2+ ions was fabricated using a perylene-3,4,9,10-tetracarboxylic acid/graphene (PTCA-GR) heterojunction. The fabricated photoelectrochemical aptasensor was based on thymine–Hg2+–thymine coordination chemistry and the plasmonic near-field absorption enhancement effect of the subsequent specific catalytic formation of nanogold. The energetic electrons from the surface plasmons of the nanogold were injected into the LUMO orbit of the organic PTCA semiconductor and then rapidly transferred to the electrode through GR due to the possible Hg2+-DNA molecular wires following irradiation with the visible light (λ > 450 nm) and at a bias voltage of 0.2 V. The fabricated aptasensor was linear in its response to the concentration of Hg2+ ions in the range of 5–500 pmol L–1, with a detection limit of 2 pmol L–1. The presence of up to 200-fold greater concentrations of other common metal ions did not interfere with the detection of Hg2+ ions in an aqueous system, and the results corresponded well with those obtained by ICP-MS. This novel plasmon-enhanced photoelectrochemical aptasensor exhibited good performance with its high sensitivity, good selectivity, low cost, and portable features. The strategy of the localized surface plasmon resonance through the in situ generation of noble metal nanoparticles paves the way for improvements in PEC aptasensor performance.
Co-reporter:Ling Yuan, Suli Liu, Wenwen Tu, Zengsong Zhang, Jianchun Bao, and Zhihui Dai
Analytical Chemistry 2014 Volume 86(Issue 10) pp:4783
Publication Date(Web):April 28, 2014
DOI:10.1021/ac403920q
Photopolymerization strategy, as one of the immobilization methods, has attracted considerable interest because of some advantages, such as easy operation, harmlessness to the biomolecules, and long storage stability. (E)-4-(4-Formylstyryl) pyridine (formylstyrylpyridine) was prepared through Heck reaction and used as a photopolymer material to immobilize biomimetic superoxide dismutase under ultraviolet irradiation (UV) irradiation in a short time. The styrylpyridinium moiety of Formylstyrylpyridine was photoreactive and formed a dimer under UV irradiation. Mn2P2O7 multilayer sheet, a novel superoxide dismutase mimic, was synthesized. The formed photopolymer can immobilize Mn2P2O7 firmly under UV irradiation. On the basis of high catalytic activity of Mn2P2O7 biomimetic enzyme and long-term stability of Mn2P2O7–formylstyrylpyridine film, after introducing multiwalled carbon nanotubes (MWCNTs), a novel electrochemical biosensing platform called MWCNTs/Mn2P2O7–formylstyrylpyridine for superoxide anion (O2•–) detection was constructed. The biosensor displayed good performance for O2•– detection and provided a reliable platform to adhere living cells directly on the modified electrode surface. Therefore, the biosensor was successfully applied to vitro determination of O2•– released from living cells, which had a promising prospect for living cells monitoring and diagnosis of reactive oxygen species-related diseases.
Co-reporter:Suli Liu, Long Zhang, Yanrong Li, Min Han, Zhihui Dai, and Jianchun Bao
Inorganic Chemistry 2014 Volume 53(Issue 16) pp:8548-8554
Publication Date(Web):August 1, 2014
DOI:10.1021/ic501128n
PbS/PbI2 nanocomposites were prepared by choosing K[PbI3] as both a lead salt and an iodide precursor and acetone/water as a reaction medium. It was found that the amount of the PbI2 component could be controlled, to some extent, by varying the amount of water used. Further, this simple bicomponent precursor-based synthetic route can be extended to prepare other lead-containing nanocomposites such as Pb3O4/PbI2 and PbSe/PbI2. Because of the heavy-atom effect, PbS/PbI2 nanocomposites exhibited good and composition-dependent electrogenerated chemiluminescence (ECL) performance, demonstrating their potential in the development of novel ECL sensors for analytical and clinical applications. These interesting findings would encourage us to gain deep insight on these phenomena, which could lead to the further development of these new inorganic materials and their applications.
Co-reporter:Xiaosi Zhou ; Xiaoshu Zhu ; Xia Liu ; Yan Xu ; Yunxia Liu ; Zhihui Dai ;Jianchun Bao
The Journal of Physical Chemistry C 2014 Volume 118(Issue 39) pp:22426-22431
Publication Date(Web):September 7, 2014
DOI:10.1021/jp5064403
Hard carbons have been extensively investigated as anode materials for sodium-ion batteries due to their disordered structure and large interlayer distance, which facilitates sodium-ion uptake and release. Herein, we report a graphene-templated carbon (GTC) hybrid via a facile two-step strategy involving a graphene oxide-directed self-assembly process and subsequent pyrolysis treatment. When evaluated as an anode material for sodium-ion batteries, the GTC electrode exhibits ultralong cycling stability and excellent rate capability. A reversible capacity of 205 mA h g–1 and more than 92% capacity retention were achieved after 2000 cycles at a current density of 200 mA g–1. Even at 10 A g–1 a high reversible capacity of 45 mA h g–1 can be obtained. The superior electrochemical performance is due to the strong coupling effect between graphitic nanocrystallites and the graphene template and the large interlayer distance of the graphitic nanocrystallites, both of which can not only effectively relieve the sodiation-induced stress and preserve the electrode integrity during cycling but also promote the electron and sodium-ion transport.
Co-reporter:Yan Xu ; Xiaoshu Zhu ; Xiaosi Zhou ; Xia Liu ; Yunxia Liu ; Zhihui Dai ;Jianchun Bao
The Journal of Physical Chemistry C 2014 Volume 118(Issue 49) pp:28502-28508
Publication Date(Web):November 21, 2014
DOI:10.1021/jp509783h
Ge nanoparticles/C composites are desirable electrode materials for high energy and power density lithium-ion batteries. However, the production of well-dispersed Ge nanoparticles in a carbon network remains a challenge because of rapid grain growth during high-temperature thermal reduction. Herein, we report a PVP-assisted hydrolysis approach for fabricating a Ge nanoparticles/reduced graphene oxide composite (denoted as Ge/RGO) made of ∼5 nm Ge nanoparticles that are uniformly distributed within a nitrogen-doped RGO carbon matrix. The Ge/RGO composite exhibits an initial discharge capacity of 1475 mA h g–1 and a reversible capacity of 700 mA h g–1 after 200 cycles at a current density of 0.5 A g–1. Moreover, Ge/RGO shows a capacity of 210 mA h g–1 even at a high current density of 10 A g–1. The excellent performance of the Ge/RGO composite is attributed to its unique nanostructure, including Ge nanoparticles, homogeneous particle distribution, and highly conductive RGO carbon matrix. These properties alleviate the pulverization problem, prevent Ge particle aggregation, and facilitate electron and lithium-ion transportation.
Co-reporter:Xianxiang Zeng, Jianchun Bao, Min Han, Wenwen Tu, Zhihui Dai
Biosensors and Bioelectronics 2014 Volume 54() pp:331-338
Publication Date(Web):15 April 2014
DOI:10.1016/j.bios.2013.10.057
•A low-potential and competitive photoelectrochemical biosensor was constructed under visible light irradiation.•The nanocomposites of CdSe quantum dots and TiO2 decorated reduced graphene oxide exhibited high photovoltaic conversion efficiency.•Enzymatic biocatalytic precipitation and competitive non-productive absorption of HRP were used for signal amplification.A low potential and competitive photoelectrochemical biosensing platform was developed using quantum dots sensitized titanium dioxide decorated reduced graphene oxide (TiO2–RGO) nanocomposites. The nanocomposites were prepared through electrostatic interaction between mercaptoacetic acid wrapped CdSe quantum dots with negative charge and TiO2–RGO hybrids with positive charge obtained via ultrasonic and acid treatments. Electron microscopes and spectroscopes were used to characterize the functionalized nanocomposites films of CdSe/TiO2–RGO, and the fabrication process of the photoelectrochemical biosensor. Based on the high photovoltaic conversion efficiency of CdSe/TiO2–RGO nanocomposites films, after introducing biological recognition and competitive immunoreaction, a low potential and competitive photoelectrochemical biosensor for carcinoembryonic antigen (CEA) detection was fabricated. The synergic effect of horseradish peroxide and benzo-4-chlorohexadienone decreased the background signal, leading to signal amplification. Under the light irradiation of 430 nm and the applied potential of 0 V, the biosensor detected CEA with a linear range from 0.003 to 100 ng mL−1 and the detection limit was estimated to be 1.38 pg mL−1 at a S/N of 3. It was satisfactory for clinical sample detection. The proposed competitive and low potential photoelectrochemical biosensor under irradiation of visible light exhibited good performance, which has a promising prospect in clinical diagnose.
Co-reporter:Xianxiang Zeng, Shishi Ma, Jianchun Bao, Wenwen Tu, and Zhihui Dai
Analytical Chemistry 2013 Volume 85(Issue 24) pp:11720
Publication Date(Web):November 20, 2013
DOI:10.1021/ac403408y
On the basis of the absorption and emission spectra overlap, an enhanced resonance energy transfer caused by excition-plasmon resonance between reduced graphene oxide (RGO)-Au nanoparticles (AuNPs) and CdTe quantum dots (QDs) was obtained. With the synergy of AuNPs and RGO as a planelike energy acceptor, it resulted in the enhancement of energy transfer between excited CdTe QDs and RGO-AuNPs nanocomposites. Upon the novel sandwichlike structure formed via DNA hybridization, the exciton produced in CdTe QDs was annihilated. A damped photocurrent was obtained, which was acted as the background signal for the development of a universal photoelectrochemical (PEC) platform. With the use of carcinoembryonic antigen (CEA) as a model which bonded to its specific aptamer and destroyed the sandwichlike structure, the energy transfer efficiency was lowered, leading to PEC response augment. Thus a signal-on PEC aptasensor was constructed. Under 470 nm irradiation at −0.05 V, the PEC aptasensor for CEA determination exhibited a linear range from 0.001 to 2.0 ng mL–1 with a detection limit of 0.47 pg mL–1 at a signal-to-noise ratio of 3 and was satisfactory for clinical sample detection. Since different aptamers can specifically bind to different target molecules, the designed strategy has an expansive application for the construction of versatile PEC platforms.
Co-reporter:Min Han, Min Fang, Lili Liu, Jianchun Bao, Zhihui Dai
Electrochemistry Communications 2013 Volume 35() pp:94-96
Publication Date(Web):October 2013
DOI:10.1016/j.elecom.2013.07.046
•The anodic ECL of SBA-15 in aqueous system was obtained for the first time.•The analytical application based on the ECL of SBA-15 was reported.•The detection of DA based on the ECL of SBA-15 had good selectivity.•ECL of SBA-15 can be extended to be applied in many other mesoporous silica.The anodic electrogenerated chemiluminescence (ECL) of one kind of mesoporous silica − SBA-15 in aqueous system and its analytical application based on the ECL were reported for the first time. A stable and intensive anodic ECL emission of SBA-15 with a peak value at + 1.6 V (vs Ag/AgCl) in air saturated, 0.1 M pH 8.0 PBS at an indium tin oxide was obtained. Using dopamine as an analyte model, it can efficiently quench the ECL intensity of SBA-15 by energy transfer. Both ascorbic acid and uric acid and some cations, which were common interferences, did not interfere the detection in practical biological samples. Most important and interesting aspect of this work was that the ECL of SBA-15 could be extended to be applied in many other mesoporous silica. SBA-15 had an enhanced anodic electrochemiluminescence which would promote the application in fabricating sensors for chemical and biochemical analysis.Most important and interesting aspect of this work is that the ECL of SBA-15 could be extended to be applied in many other mesoporous silica.
Co-reporter:Jinxing Zhang, Suli Liu, Jianchun Bao, Wenwen Tu and Zhihui Dai
Analyst 2013 vol. 138(Issue 18) pp:5396-5403
Publication Date(Web):24 Jun 2013
DOI:10.1039/C3AN00705G
A novel electrochemiluminescence (ECL) immunosensor for highly sensitive detection of α-fetoprotein (AFP) based on a dual signal amplification strategy was developed. Zinc oxide (ZnO) nanoparticles were employed as the carriers for immobilizing the capture AFP antibody (Ab1) and CdSe quantum dots (QDs). CdSe QDs-functionalized ZnO nanoparticles were used as the tracer to label the signal AFP antibody (Ab2). CdSe QDs-functionalized ZnO nanoparticles were prepared through an amide dehydration reaction and they were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The Ab2 was bound to the CdSe QDs-functionalized ZnO nanoparticles to obtain the detection probe. ZnO nanoparticles could accelerate electron transfer between the detection probe and the electrode, and their large surface area was beneficial for loading more CdSe QDs, leading to an enhanced ECL signal (0.9-fold increase) by a sandwich immunoreaction. This also indicated efficient association of the detection probe on the immunosensor surface. The designed immunoassay showed a wide linear range from 0.5 to 600 ng mL−1 with a detection limit of 0.48 ng mL−1 at a S/N ratio of 3 for AFP detection. The ECL immunosensor exhibited good analytical performance and was successfully applied to clinical sample detection, showing a promising application in ECL biosensing.
Co-reporter:Ling Yuan, Yaqian Lan, Min Han, Jianchun Bao, Wenwen Tu and Zhihui Dai
Analyst 2013 vol. 138(Issue 11) pp:3131-3134
Publication Date(Web):28 Mar 2013
DOI:10.1039/C3AN00041A
A label-free electrochemical biosensing platform has been developed for the first time using carbon nanotubes for facile detection of malondialdehyde, showing high sensitivity and acceptable selectivity with a low detection limit of 0.047 μmol L−1 and a linear response ranging from 0.1 to 90 μmol L−1.
Co-reporter:Kun Wang, Tianxiang Wei, Wenwen Tu, Min Han and Zhihui Dai
Analytical Methods 2013 vol. 5(Issue 8) pp:1909-1914
Publication Date(Web):28 Feb 2013
DOI:10.1039/C3AY26541B
A sandwich-type electrochemical immunosensor for the detection of alpha-fetoprotein based on a Au–antibody nanocomposite thin film as an electrode platform which was prepared by a liquid–liquid interface method was developed.
Co-reporter:Suli Liu, Zengsong Zhang, Jianchun Bao, Yaqian Lan, Wenwen Tu, Min Han, and Zhihui Dai
The Journal of Physical Chemistry C 2013 Volume 117(Issue 29) pp:15164-15173
Publication Date(Web):June 28, 2013
DOI:10.1021/jp4044122
The rich phase structure of Cu2Se may provide good opportunities for modulating and optimizing their catalytic properties. However, chemical synthesis of Cu2Se nanostructures with different crystal phases still is a key challenge, and their catalytic application in energy fields has not been studied. In this paper, pure tetragonal and cubic phases Cu2Se nanowires (NWs) that assembled by small nanocubes have been controllably synthesized via a simple solid–liquid phase chemical transformation method, i.e., thermal treatment of presynthesized Cu NWs in Se precursor solution containing proper surfactant and 1-octadecene. Besides reaction temperature and ripening time, the functional groups and alkyl chain length of used surfactant greatly affect the kinetics of the transformation reaction and phase structure control of Cu2Se NWs. The trioctylphosphine is found to be the optimal surfactant, which not only accelerates the transformation reaction but also improves the stable temperature of tetragonal phase Cu2Se NWs about 80 °C compared with that of their bulk counterparts. Electrochemical tests reveal that both the obtained Cu2Se NWs can be used to catalyze oxygen reduction reaction (ORR) in alkaline media. But the catalytic performance of tetragonal phase Cu2Se NWs is much higher than that of cubic phase ones, which is even better than that of commercial Pd/C and some reported non-Pt electrocatalysts. The diverse catalytic performances of those Cu2Se NWs result from their distinct spatial arrangement means of Cu and Se atoms that lead to different adsorption and activation of O2 molecules approaches, as evidenced by electrocatalytic dynamic experiments. The ORR on tetragonal phase Cu2Se NWs abides by the direct 4e– mechanism, whereas that on cubic phase ones complies with dual-path mechanism comprising both 2e– and 4e– pathways.
Co-reporter:Xiaosi Zhou, Jianchun Bao, Zhihui Dai, and Yu-Guo Guo
The Journal of Physical Chemistry C 2013 Volume 117(Issue 48) pp:25367-25373
Publication Date(Web):November 20, 2013
DOI:10.1021/jp409668m
Tin possesses a high theoretical specific capacity as anode materials for Li-ion batteries, and considerable efforts have been contributed to mitigating the capacity fading along with its huge volume expansion during lithium insertion and extraction processes, mainly through nanostructured material design. Herein, we present Sn nanoparticles encapsulated in nitrogen-doped graphene sheets through heat-treatment of the SnO2 nanocrystals/nitrogen-doped graphene hybrid. The specific architecture of the as-prepared Sn@N-RGO involves three advantages, including a continuous graphene conducting network, coating Sn surface through Sn–N and Sn–O bonding generated between Sn nanoparticles and graphene, and porous and flexible structure for accommodating the large volume changes of Sn nanoparticles. As an anode material for lithium-ion batteries, the hybrid exhibits a reversible capacity of 481 mA h g–1 after 100 cycles under 0.1 A g–1 and a charge capacity as high as 307 mA h g–1 under 2 A g–1.
Co-reporter:Min Han, Suli Liu, Linyan Zhang, Can Zhang, Wenwen Tu, Zhihui Dai, and Jianchun Bao
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 12) pp:6654
Publication Date(Web):November 16, 2012
DOI:10.1021/am301814y
In this article, the novel octopus-tentacle-like Cu nanowire-Ag nanocrystals heterostructures have been fabricated in solution phase via heterogeneous nucleation and growth of Ag nanocrystals on presynthesized Cu nanowires. The growth environment and dynamic factors of Ag nanocrystals play an important role for formation of such heterostructures. Combined the physical constants of Cu and Ag with a series of control experiments, the epitaxial growth means of Ag nanocrystals on Cu nanowire is found to abide by “layer-plus-island” (Stranski-Krastanow) mode. Because of the presence of multiple junctions and strong synergistic effect of their constituents, the obtained heterostructures exhibit greatly enhanced electrocatalytic performance toward oxygen reduction reaction compared with that of pure Ag nanocrystals, Cu nanowires, and mechanically mixed dual components as well as recently reported some non-Pt materials, which can be served as an alternative cathodic electrocatalyst to apply in alkaline fuel cells. Moreover, our method can be extended to fabricate octopus-tentacle-like Cu nanowire-Au nanocrystals and Cu nanowire-Pd nanocrystals heterostructures.Keywords: Ag nanocrystals; Cu nanowires; electrocatalysis; heterogeneous nucleation and growth; heterostructure; oxygen reduction reaction;
Co-reporter:Xiuhua Wang, Min Han, Jianchun Bao, Wenwen Tu, Zhihui Dai
Analytica Chimica Acta 2012 Volume 717() pp:61-66
Publication Date(Web):2 March 2012
DOI:10.1016/j.aca.2011.12.045
The direct electron transfer of superoxide dismutase (SOD) was greatly facilitated by sodium alginate (SA) sol–gel film with the formal potential of 0.14 V, which was just located between O2−/O2 and O2−/H2O2. The preparation of the SOD/SA modified electrode was simple without any mediators or promoters. Based on bimolecular recognition for specific reactivity of SOD/SA toward O2−, the SOD modified electrode was utilized to measure O2− with good analytical performance, such as low applied potential (0 V), high selectivity (no obvious interference), wide linear range (0.44–229.88 μM) and low detection limit (0.23 μM) in pH 7.0 phosphate buffer solution. Furthermore, it could be successfully exploited for the determination of O2− released from living cells directly adhered on the modified electrode surface. Thus, the proposed O2− biosensor, combining with the properties of SA sol–gel film, provided a novel approach for protein immobilization, direct electron transfer study of the immobilized protein and real-time determination of O2− released from living cells.Graphical abstractHighlights► The direct electron transfer of SOD was facilitated on SA sol–gel film. ► O2− sensor has high selectivity, stability and sensitivity. ► The proposed measurement for O2− can be applied in living cells.
Co-reporter:Can Zhang, Tianxiang Wei, Min Han, Wenwen Tu, Zhihui Dai
Electrochemistry Communications 2012 Volume 22() pp:133-136
Publication Date(Web):August 2012
DOI:10.1016/j.elecom.2012.06.017
A novel and universal electrochemical strategy for monitoring DNA was developed based on specific cleavage of MspI endonuclease combining with streptavidin–horseradish peroxidase (SA–HRP) conjugate. By introducing the strategy to mycobacterium tuberculosis (MTB) DNA detection, the probe DNA was immobilized on Au electrode via AuS bond and SA–HRP conjugate was linked to probe DNA by biotin–SA specific interaction, which led to the first application in MTB DNA electrochemical detection. This proposed electrochemical method exhibited satisfactory performance which could detect MTB DNA linearly ranging from 10 pM to 100 nM with a detection limit of 2.3 pM. The novel strategy of DNA analysis showed a promising application in clinic diagnostics.Highlights► A signal amplification strategy using MspI endonuclease and HRP was designed. ► A novel and universal electrochemical platform for monitoring DNA was developed. ► A wide concentration range and low detection limit toward detection of MTB DNA.
Co-reporter:Min Han, Suli Liu, Xiaopeng Nie, Dan Yuan, Peipei Sun, Zhihui Dai and Jianchun Bao
RSC Advances 2012 vol. 2(Issue 14) pp:6061-6067
Publication Date(Web):01 May 2012
DOI:10.1039/C2RA20119D
In this paper, small-sized monodisperse Ag nanocrystals (NCs) have been successfully synthesized at gram-scale by thermal reduction of a large amount of solid AgNO3 (more than 10 mmol) with dodecylamine in 1-octadecene solvent. The formation process of the Ag NCs is different from that of a conventional homogeneous phase synthetic system. According to the temperature- and time-dependent experiments, a high temperature “digestive ripening” mechanism is suggested to elucidate their formation process. The size of Ag NCs can be easily controlled by the amount of solid AgNO3 added and the reaction temperature. Furthermore, the obtained Ag NCs are found to possess extraordinary catalytic activity, which can catalyze a series of Sonogashira reactions with high yield. Interestingly, under identical conditions, their catalytic activities are higher than that of similar sized Pd NCs, showing great promise for the substitution of conventional Pd-based catalysts to apply in the Sonogashira reaction. This developed synthetic strategy together with the fundamental understanding of heterogeneous nucleation and growth has great potential towards the contriving rational route for mass production of nanomaterials for advanced catalytic and other functional applications.
Co-reporter:Min Han, Dan Yuan, Suli Liu, Jianchun Bao, Zhihui Dai, Jianming Zhu
Materials Research Bulletin 2012 47(12) pp: 4438-4444
Publication Date(Web):
DOI:10.1016/j.materresbull.2012.09.044
Co-reporter:Min Han, Suli Liu, Jianchun Bao, Zhihui Dai
Biosensors and Bioelectronics 2012 Volume 31(Issue 1) pp:151-156
Publication Date(Web):15 January 2012
DOI:10.1016/j.bios.2011.10.008
The spherical porous Pd nanoparticle assemblies (NPAs) have been successfully synthesized by starch-assisted chemical reduction of Pd(II) species at room temperature. Such Pd NPAs are not simply used to enlarge the surface area and to promote the electron transfer. They also catalyze the reduction of H2O2 which are regarded as horseradish peroxidase (HRP) substitutes in electron transfer process. By using them as electrocatalysts, as low as 6.8 × 10−7 M H2O2 can be detected with a linear range from 1.0 × 10−6 to 8.2 × 10−4 M. Moreover, through co-immobilization of such Pd NPAs and glucose oxidase (GOx), a sensitive and selective glucose biosensor is developed. The detection principle lies on measuring the increase of cathodic current by co-reduction of dissolved oxygen and the in situ generated H2O2 during the enzymatic reaction. Under optimal conditions, the detection limit is down to 6.1 × 10−6 M with a very wide linear range from 4.0 × 10−5 to 2.2 × 10−2 M. The proposed biosensor shows a fast response, good stability, high selectivity and reproducibility of serum glucose level. It provides a promising strategy to construct fast, sensitive, stable and anti-interferential amperometric biosensors for early diagnosis and prevention of diabetes.Highlights► The spherical porous Pd nanostructures have been synthesized by a simple method. ► Such Pd can promote the electron transfer and catalyze the reduction of H2O2. ► They are used as horseradish peroxidase substitutes in electron transfer process. ► Based on the Pd and glucose oxidase, a sensitive glucose biosensor is developed. ► This biosensor provides a strategy for early diagnosis and prevention of diabetes.
Co-reporter:Xuelin Fang, Min Han, Guofei Lu, Wenwen Tu, Zhihui Dai
Sensors and Actuators B: Chemical 2012 Volume 168() pp:271-276
Publication Date(Web):20 June 2012
DOI:10.1016/j.snb.2012.04.022
A competitive immunosensor using CdSe quantum dots (QDs) as a label was highly proposed for the detection of a tumor marker. CdSe QDs were characterized by transmission electron microscope image, photoluminescence spectra and ultraviolet–visible absorption spectra. The fabrication process of the immunosensor was traced with electrochemical impedance spectra. Using α-fetoprotein (AFP) as a model, a simple electrochemiluminescence immunosensing platform based on CdSe QDs using competitive binding between conjugated antibody-CdSe QDs and free AFP with immobilized AFP on Au electrode was developed. Under the optimum conditions, the proposed electrochemiluminescence method could detect AFP ranging from 0.05 to 100 μg/L with a detection limit of 0.005 μg/L. The proposed immunosensor showed good analytical performance and was successfully applied to detecting level of AFP in human serum samples, which would provide a new and promising direction for clinical application.
Co-reporter:Yanfen Li, Min Han, Hongyan Bai, Yong Wu, Zhihui Dai, Jianchun Bao
Electrochimica Acta 2011 Volume 56(Issue 20) pp:7058-7063
Publication Date(Web):1 August 2011
DOI:10.1016/j.electacta.2011.05.119
A novel aptamer biosensor with easy operation and good sensitivity, specificity, stability and reproducibility was developed by immobilizing the aptamer on water soluble CdSe quantum dots (QDs) modified on the top of the glassy carbon electrode (GCE). Methylene blue (MB) was intercalated into the aptamer sequence and used as an electrochemical marker. CdSe QDs improved the electrochemical signal because of their larger surface area and ion centers of CdSe QDs may also had a major role on amplifying the signal. The higher ion concentration caused more combination of aptamer which caused larger signal. The thrombin was detected by differential pulse voltammetry (DPV) quantitatively. Under optimal conditions, the two linear ranges were obtained from 3 to 13 μg mL−1 and from 14 to 31 μg mL−1, respectively. The detection limit was 0.08 μg mL−1 at 3σ. The constructed biosensor had better responses compared with that in the absence of the CdSe QDs immobilizing. The control experiment was also carried out by using BSA, casein and IgG in the absence of thrombin. The results showed that the aptasensor had good specificity, stability and reproducibility to the thrombin. Moreover, the aptasensor could be used for detection of real sample with consistent results in comparison with those obtained by fluorescence method which could provide a promising platform for fabrication of aptamer based biosensors.
Co-reporter:Qian Liu, Min Han, Jianchun Bao, Xiaoqing Jiang and Zhihui Dai
Analyst 2011 vol. 136(Issue 24) pp:5197-5203
Publication Date(Web):27 Sep 2011
DOI:10.1039/C1AN15581D
A sensitive and specific immunoassay method for detecting α-fetoprotein (AFP) based on electrogenerated chemiluminescence (ECL) was described. ECL could perform detection for a series of different concentrations of AFP. CdSe quantum dots (QDs) were used as labels and were linked to AFP antibody (anti-AFP, the secondary antibody, Ab2*). Immunoassay was carried out on a modified electrode using a sandwich assay approach, where anti-AFP (Ab1) was covalently bound to the surface of an Au electrode to be allowed to capture AFP specifically. Afterwards, Ab2* was allowed to bind selectively to the captured AFP. The non-specific adsorption was negligible. In the presence of H2O2, the ECL intensity increased with the increase of AFP, which indicated that an immunosensor for AFP was constructed. The detection of AFP based on measuring the ECL intensity of CdSe without the enzyme and mediator can promote the stability of the immunosensor. The linear range of the AFP assay was from 0.002 to 32 ng mL−1. Furthermore, the immunosensor showed high sensitivity, good precision, stability, and reproducibility and could be used for the detection of real samples with consistent results in comparison with those obtained by the enzyme-linked immunosorbent assay (ELISA) method. The strategy was successfully demonstrated as a simple, cost-effective, specific, and potential method to detect AFP in practical samples.
Co-reporter:Yanfen Li, Jianchun Bao, Min Han, Zhihui Dai, Huaisheng Wang
Biosensors and Bioelectronics 2011 Volume 26(Issue 8) pp:3531-3535
Publication Date(Web):15 April 2011
DOI:10.1016/j.bios.2011.01.039
A simple method to amplify the electrochemical signal by an aptamer with 22 bases modified with CdS hollow nanospheres (CdSHNs) was described. Using the thrombin as a model, the interaction between the aptamer and CdSHNs was characterized by cyclic voltammetry, electrochemical impedance spectroscopy and circular dichroism spectroscopy. CdSHNs promoted the electron transfer between the gold electrode and K3[Fe(CN)6] and facilitated the conformation conversion of the aptamer from hairpin to G-quadruplex after the aptamer interacted with thrombin. Under optimal conditions, the modified electrode could be used for the determination of thrombin from 0 to 33 μg mL−1 and the sensitivity was 1.34 μA mL μg−1 cm−2, while the linear range of the modified electrode without the immobilization of CdSHNs was from 2.75 to 27.5 μg mL−1 and the sensitivity was 0.062 μA mL μg−1 cm−2. This constructed biosensor also had a good stability, specificity, reproducibility and accuracy which could provide a promising platform for fabrication of aptamer based biosensors.
Co-reporter:Dr. Min Han;Yanrong Li;Hongyan Niu;Lili Liu; Kunji Chen; Jianchun Bao; Zhihui Dai; Jianming Zhu
Chemistry - A European Journal 2011 Volume 17( Issue 13) pp:3739-3745
Publication Date(Web):
DOI:10.1002/chem.201002066
Abstract
Spherical PbSe hollow nanostructure assemblies (HNSAs) were synthesized by a simple one-pot solid/liquid-phase reaction in which solid KPbI3⋅2 H2O and SeO2 are heated in oleic acid/dodecylamine/1-octadecene at 250 °C for 30 min. XRD analysis shows that the obtained product is cubic-phase PbSe and well crystallized. FESEM and TEM images reveal that the obtained spherical PbSe assemblies are made up of small, irregular, and fused hollow nanostructure building blocks. On the basis of temperature- and time-dependent investigations as well as control experiments, molten-salt corrosion of solid PbSe nanocrystal aggregates formed in situ during the high-temperature ripening stage is suggested to explain the formation of such novel assemblies. Moreover, when the reaction temperature is further increased to 280 or 320 °C with other conditions unchanged, cubic and orthorhombic mixed-phase PbSe HNSAs is generated. The obtained PbSe HNSAs exhibit excellent electrogenerated chemiluminescence (ECL) performance. Two strong and stable emission peaks at about −1.4 and +1.5 V (vs. Ag/AgCl) are observed. In particular, the ECL intensity is influenced by the crystal phase of PbSe.
Co-reporter:Hongyan Bai, Min Han, Yuezhi Du, Jianchun Bao and Zhihui Dai
Chemical Communications 2010 vol. 46(Issue 10) pp:1739-1741
Publication Date(Web):07 Jan 2010
DOI:10.1039/B921004K
Porous tubular palladium nanostructures were synthesized by electrodeposition of palladium into a CdS modified alumina template and subsequent removal of CdS; the nanostructures provided a promising platform for the fabrication of nonenzymatic glucose sensors.
Co-reporter:Qinshu Zhu, Min Han, Huaisheng Wang, Lili Liu, Jianchun Bao, Zhihui Dai and Jian Shen
Analyst 2010 vol. 135(Issue 10) pp:2579-2584
Publication Date(Web):09 Aug 2010
DOI:10.1039/C0AN00306A
The electrogenerated chemiluminescence (ECL) from nanometre-sized CdS hollow spheres and carbon nanofiber (CdSHS-CNF) nanocomposites in aqueous solution and their sensing applications were studied by entrapping them in carbon paste. The CdSHS-CNF nanocomposites exhibited a peak at −1.02 V (vs. Ag/AgCl) in 0.1 M pH 8.0 PBS containing 20 mM H2O2 during the cyclic sweep between 0 and −1.2 V at 40 mV s−1. Compared with CdS hollow spheres (CdSHS), carbon nanofiber (CNF) and CdS nanocrystals and carbon nanofiber (CdSNC-CNF) nanocomposites, CdSHS-CNF not only enhanced the electrochemiluminescent intensity but also decreased the ECL starting potentials. Furthermore, by immobilizing cholesterol oxidase (ChOx) on CdSHS-CNF nanocomposites modified electrode, a sensitive and selective method was developed for detection of cholesterol using oxygen as a coreactant which captured more electrons from electrochemically reduced CdSHS-CNF than H2O2. Under optimal conditions, the sensor could be used for the determination of cholesterol from 1 × 10−6 to 4.4 × 10−4 M with a correlation coefficient of 0.9991 and a detection limit was 8 × 10−7 M at 3σ. The unique ECL intensity and stability of CdSHS-CNF would promote the application of nanometre-sized semiconductor hollow spheres based composites in fabricating sensors for chemical and biochemical analysis.
Co-reporter:Yanfen Li, Hongyan Bai, Qian Liu, Jianchun Bao, Min Han, Zhihui Dai
Biosensors and Bioelectronics 2010 Volume 25(Issue 10) pp:2356-2360
Publication Date(Web):15 June 2010
DOI:10.1016/j.bios.2010.03.036
Porous tubular silver (Ag) nanoparticles were successfully synthesized by electrodeposition of Ag into cadmium sulfide (CdS) modified porous anodic alumina (PAA) template and removal of CdS subsequently. Only the solid nanorods were obtained without CdS. The strong affinity between S2− and Ag (I) caused preferential deposition of Ag on the pore walls to form tubular Ag. After removal of CdS, porous tubular Ag nanoparticles were obtained. This novel nanostructure was characterized by XRD, TEM, FESEM, EDS and nitrogen adsorption–desorption isotherms. Using porous tubular Ag nanoparticles modified glassy carbon electrode (GCE) as a working electrode, a good nonenzymatic cholesterol sensor was constructed, which showed markedly improved electrocatalytic activity toward cholesterol oxidation compared to that of solid Ag nanorods. Under optimal detection conditions, the constructed sensor had a linear response range of 2.8 × 10−4 M to 3.3 × 10−2 M and the detection limit was 1.8 × 10−4 M at a signal-to-noise ratio of 3. The biosensor showed an acceptable reproducibility, good stability and low interferences. To the best of our knowledge, it is the first example of a nonenzymatic cholesterol biosensor based on Ag nanoparticles. The experimental results demonstrated that porous tubular Ag nanoparticles provided a promising platform for rational design and fabrication of nonenzymatic cholesterol sensors.
Co-reporter:YanRong Li;ZhiYong Gan;YanFen Li;Qian Liu;JianChun Bao
Science China Chemistry 2010 Volume 53( Issue 4) pp:820-825
Publication Date(Web):2010 April
DOI:10.1007/s11426-010-0105-0
This paper reports a simple method for immobilization of acetylcholinesterase (AChE) on one-dimensional (1D) gold (Au) nanoparticles for detection of organophosphorous (OP) insecticides. 1D Au nanoparticles were prepared by electrodeposition in the pores of an alumina template which was subsequently removed by 2.0 M NaOH solution. They were characterized by XRD and FESEM. The immobilized AChE retained its biological activity and catalyzed the hydrolysis of acetylthiocholine to form thiocholine, which was subsequently oxidized to produce detectable signals. Based on the inhibition toward the enzymatic activity of AChE by OP insecticides, sensitive detection of methamidophos (an OP insecticide) was performed. Under optimal conditions, the sensors could be used for the determination of methamidophos ranging from 0.004 to 24 μg/mL with the detection limit of 0.001 μg/mL. The developed OP insecticide biosensors exhibited satisfactory stability and reproducibility. This work demonstrated that 1D Au nanoparticles could serve as an ideal carrier for immobilization of AChE to fabricate the corresponding biosensor.
Co-reporter:Yucui Han, Shaohua Liu, Min Han, Jianchun Bao and Zhihui Dai
Crystal Growth & Design 2009 Volume 9(Issue 9) pp:3941-3947
Publication Date(Web):July 10, 2009
DOI:10.1021/cg900066z
The dendritic Ag nanostructure with ordered branches and a “clean” surface has been successfully prepared via a facile surfactant-free and acetone-based mixed solvents route at room temperature. Experiments and structural characterizations reveal that the dendritic Ag nanostructure is evolved from the initially generated triangular nanoplates by the reaction of AgNO3 with l-ascorbic acid to the dendrites through both the Ostwald ripening and the oriented attachment growth processes. The acetone plays the key role in controlling the nucleation, growth, conversion, and assembly of the Ag nanoparticles. In the absence of acetone, only the polyhedral particles can be obtained. The yield of the dendrites is dependent on the volume ratio of acetone to water. The present work provides an example for the synthesis of a novel metal nanostructure by simply adjusting the solvent components, which is important for the qualitative understanding of the solvent effect on the morphology of nanostructures and the controllable synthesis of desired nanostructures. The dendritic Ag nanostructure possesses surface-enhanced Raman scattering (SERS) performance similar to that from triangular Ag nanoplates, and they both show much better SERS enhancement ability than that of polyhedral Ag particles which might be relative to their different geometric shapes and microstructures. It is expected that the dendritic Ag nanostructure may find potential applications such as in catalysis, molecular probe, and biological sensing.
Co-reporter:Zhihui Dai, Guojian Shao, Jianmin Hong, Jianchun Bao, Jian Shen
Biosensors and Bioelectronics 2009 Volume 24(Issue 5) pp:1286-1291
Publication Date(Web):1 January 2009
DOI:10.1016/j.bios.2008.07.047
A tetragonal pyramid-shaped porous ZnO (TPSP-ZnO) nanostructure is used for the immobilization, direct electrochemistry and biosensing of proteins. The prepared ZnO has a large surface area and good biocompatibility. Using glucose oxidase (GOD) as a model, this shaped ZnO is tested for immobilization of proteins and the construction of electrochemical biosensors with good electrochemical performances. The interaction between GOD and TPSP-ZnO is examined by using AFM, N2 adsorption isotherms and electrochemical methods. The immobilized GOD at a TPSP-ZnO-modified glassy carbon electrode shows a good direct electrochemical behavior, which depends on the properties of the TPSP-ZnO. Based on a decrease of the electrocatalytic response of the reduced form of GOD to dissolved oxygen, the proposed biosensor exhibits a linear response to glucose concentrations ranging from 0.05 to 8.2 mM with a detection limit of 0.01 mM at an applied potential of −0.50 V which has better biosensing properties than those from other morphological ZnO nanoparticles. The biosensor shows good stability, reproducibility, low interferences and can diagnose diabetes very fast and sensitively. Such the TPSP-ZnO nanostructure provides a good matrix for protein immobilization and biosensor preparation.
Co-reporter:Jianmin Hong, Zhihui Dai
Sensors and Actuators B: Chemical 2009 Volume 140(Issue 1) pp:222-226
Publication Date(Web):18 June 2009
DOI:10.1016/j.snb.2009.04.032
Hemoglobin (Hb) was immobilized on one-dimensional (1D) gold (Au) nanoparticles to construct a novel amperometric biosensor for hydrogen peroxide (H2O2) and nitrite (NO2−). 1D Au nanoparticles were prepared by electrodepositon in the pores of an alumina template and were characterized by XRD and TEM. The immobilized Hb retained its biological activity well and displayed a good response to the reduction of both H2O2 and NO2−. Its apparent Michaelis–Menten constants for H2O2 and NO2− were 10.8 and 35.3 μM, respectively, showing a good affinity. Under optimal conditions, the biosensors could be used for the determination of H2O2 ranging from 0.6 to 12.4 μM and NO2− ranging from 0.4 to 14.8 μM. The detection limits were 2.4 × 10−8 and 6.5 × 10−8 M at 3σ, respectively. 1D Au nanoparticles provided a good matrix for protein immobilization and biosensor preparation.
Co-reporter:Li-li Liu, Jian-chun Bao, Min Fang, Lai-fa Li, Zhi-hui Dai
Sensors and Actuators B: Chemical 2009 Volume 139(Issue 2) pp:527-531
Publication Date(Web):4 June 2009
DOI:10.1016/j.snb.2009.02.066
A novel electrogenerated chemiluminescence (ECL) sensor for the detection of amino acid based on the immobilized Ru(bpy)32+ on dendritic Pd nanoparticle was firstly developed. The primary amino acid (leucine) was derivatized by reacting with acetaldehyde. The electrochemical and ECL behaviors of the immobilized Ru(bpy)32+ were investigated. The modified electrode showed an increased electrocatalytic response to the oxidation of the derivatized leucine, producing a sensitized ECL signal probably since a high fraction of surface atoms located on the tips of the dendrites and a large amount of Ru(bpy)32+ was immobilized on the electrode. Under optimal conditions, the sensor could be used for the determination of leucine with a linear range from 3.0 to 182 μM and a detection limit of 1.0 μM at 3σ. Furthermore, the present ECL sensor displayed a long-term stability. Our interference experiments indicated that acetaldehyde derivatives of other amino acids, such as proline and valine can be completely separated by electrophoresis (CE).
Co-reporter:Z.-H. Dai;F.-X. Liu;G.-F. Lu;J.-C. Bao
Journal of Solid State Electrochemistry 2008 Volume 12( Issue 2) pp:175-180
Publication Date(Web):2008 February
DOI:10.1007/s10008-007-0378-1
The oxidation of NADH on electropolymerizing methylene green (MG)-modified glassy carbon electrode (GCE) is described. The modified electrode shows an excellent electrocatalytic activity toward NADH oxidation, reducing its overpotential by about 650 mV and exhibits a wide linear range of 5.6–420 μM NADH with the detection limit of 3.8 μM. The electrode displays a good reproducibility and stability and the coexisting species does not affect the determination of NADH. The application in the amperometric biosensing of ethanol using alcohol dehydrogenase enzyme (ADH) also has been demonstrated with this electrode. MG-modified GCE can not only be used to detect NADH in biochemical reaction, but also can be used as the potential matrix of the construction of dehydrogenases biosensor.
Co-reporter:Zhihui Dai, Jianchun Bao, Xiaodi Yang, Huangxian Ju
Biosensors and Bioelectronics 2008 Volume 23(Issue 7) pp:1070-1076
Publication Date(Web):28 February 2008
DOI:10.1016/j.bios.2007.10.015
A novel bienzyme-channeling sensor was constructed by entrapping glucose oxidase (GOD) and horseradish peroxidase (HRP) in the mesopores of well-ordered hexagonal mesoporous silica structures (SBA-15). The SBA-15 mesoporous materials accelerated the electron transfer between the entrapped HRP and electrode. Both HRP and GOD retained their catalytic activities in the bienzyme-entrapped SBA-15 film. In presence of glucose the enzymatic reaction of GOD-glucose-dissolved oxygen system generated hydrogen peroxide in the bienzyme-entrapped mesopores, which was immediately reduced at −0.40 V by an electrocatalytic reaction with the HRP entrapped in the same mesopore to lead to a sensitive and fast amperometric response. Thus the bienzyme channeling could be used for the detection of glucose with excellent performance without the addition of any mediator. Optimization of the experimental parameters was performed with regard to pH, operating potential and temperature. The detection limit was down to 2.7 × 10−7 M with a very wide linear range from 3.0 × 10−6 to 3.4 × 10−2 M. The constructed bienzyme channeling provided a strategy for amperometric detection of oxidase substrates by co-entrapping the corresponding oxidase and HRP in the mesoporous materials.
Co-reporter:Zhihui Dai, Min Fang, Jianchun Bao, Huaisheng Wang, Tianhong Lu
Analytica Chimica Acta 2007 Volume 591(Issue 2) pp:195-199
Publication Date(Web):22 May 2007
DOI:10.1016/j.aca.2007.03.063
We have constructed a glucose biosensor by immobilizing glucose oxidase (GOD) on titanium-containing MCM-41 (Ti-MCM-41) modified screen-printed electrodes. The strategy of the sensing method is to monitor the extent of the decrease of the reduction current of O2 upon adding glucose at a selected potential. The detection can be done at the applied potential of −0.50 V and can efficiently exclude the interference from commonly coexisted substances. The constructed sensor has a high sensitivity to glucose (5.4 mAM−1 cm−2) and a linear response range of 0.10–10.0 mM. The detection limit is 0.04 mM at a signal-to-noise ratio of 3. The sensor also shows high stability and remains its catalytic activity up to 60 °C. The biocompatibility of Ti-MCM-41 means that this immobilization matrix not only can be used for immobilizing GOD but also can be extended to other enzymes and bioactive molecules, thus providing a promising platform for the development of biosensors.
Co-reporter:Jisen Li, Yuyun Chen, Yujia Tang, Shunli Li, Huiqing Dong, Kui Li, Min Han, Ya-Qian Lan, Jianchun Bao and Zhihui Dai
Journal of Materials Chemistry A 2014 - vol. 2(Issue 18) pp:NaN6319-6319
Publication Date(Web):2014/01/29
DOI:10.1039/C3TA15335E
A novel MOF-templated nitrogen and sulphur co-doped porous material has been synthesized as an efficient electrocatalyst for oxygen reduction reactions (ORRs) for the first time. The representative NS(3:1)–C-MOF-5 catalyst shows the highest onset potential, and is even comparable to commercial Pt–C catalyst, due to the synergistic effect of N and S co-doping.
Co-reporter:Tianxiang Wei, Yuyun Chen, Wenwen Tu, Yaqian Lan and Zhihui Dai
Chemical Communications 2014 - vol. 50(Issue 66) pp:NaN9360-9360
Publication Date(Web):2014/06/26
DOI:10.1039/C4CC03555K
A versatile label-free, stable, low-cost and simple electrochemical biosensing platform has been developed based on a phosphomolybdic acid anion probe by jointly taking advantages of its native electronegativity, electrochemical activity and chemisorption with graphene oxide.
Co-reporter:Yuyun Chen, Min Han, Yujia Tang, Jianchun Bao, Shunli Li, Yaqian Lan and Zhihui Dai
Chemical Communications 2015 - vol. 51(Issue 62) pp:NaN12380-12380
Publication Date(Web):2015/06/23
DOI:10.1039/C5CC02717A
Novel polypyrrole–polyoxometalate/reduced graphene oxide ternary nanohybrids (TNHs) are synthesized via a one-pot redox relay strategy. The TNHs exhibit high areal specific capacitance (2.61 mF cm−2), and the fabricated solid device also exhibits good rate capability, excellent flexibility and mechanical stability.
Co-reporter:Ji-Sen Li, Shun-Li Li, Yu-Jia Tang, Min Han, Zhi-Hui Dai, Jian-Chun Bao and Ya-Qian Lan
Chemical Communications 2015 - vol. 51(Issue 13) pp:NaN2713-2713
Publication Date(Web):2015/01/05
DOI:10.1039/C4CC09062D
A novel nitrogen-doped Fe/Fe3C@graphitic layer/carbon nanotube hybrid derived from MOFs has been first fabricated by a facile approach. The hybrid exhibited outstanding bifunctional electrocatalytic activity for ORR and OER, due to the merits of graphitic layer/carbon nanotube structures with highly active N and Fe/Fe3C sites.
Co-reporter:Shanshan Liu, Huijuan Cao, Zhaoyin Wang, Wenwen Tu and Zhihui Dai
Chemical Communications 2015 - vol. 51(Issue 75) pp:NaN14262-14262
Publication Date(Web):2015/07/31
DOI:10.1039/C5CC04092B
A universal and label-free photoelectrochemical cytosensing strategy was designed based on resonance energy transfer (RET) between carbon dots and cysteamine capped gold nanoparticles. RET promoted photo-to-current conversion efficiency and enhanced detection sensitivity. This proposed photoelectrochemical cytosensing platform exhibited a good performance for the assay of tumor cells with overexpressed receptors on cells.
Co-reporter:Jing Lou, Zhaoyin Wang, Xiao Wang, Jianchun Bao, Wenwen Tu and Zhihui Dai
Chemical Communications 2015 - vol. 51(Issue 78) pp:NaN14581-14581
Publication Date(Web):2015/08/11
DOI:10.1039/C5CC06156C
A “signal-on” electrochemiluminescent DNA biosensing platform was proposed based on the dual quenching and strand displacement reaction. This novel “signal-on” detection strategy revealed its sensitivity in achieving a detection limit of 2.4 aM and its selectivity in distinguishing single nucleotide polymorphism of target DNA.
Co-reporter:Jing Li, Wenwen Tu, Hongbo Li, Jianchun Bao and Zhihui Dai
Chemical Communications 2014 - vol. 50(Issue 17) pp:NaN2110-2110
Publication Date(Web):2014/01/02
DOI:10.1039/C3CC49109A
A robust aptasensor for Ag+ was proposed for the first time using an enhanced ZnO nanorod-based photoelectrochemistry by in situ generated AgBr via layer-by-layer assembly. This work opens up new avenues for application of one-dimensional ZnO nanorod arrays in photoelectrochemical sensing. Additionally, the strategy of employing in situ generated narrow-bandgap semiconductors paves a new way for photoelectrochemical sensing.
Co-reporter:Hongyan Bai, Min Han, Yuezhi Du, Jianchun Bao and Zhihui Dai
Chemical Communications 2010 - vol. 46(Issue 10) pp:NaN1741-1741
Publication Date(Web):2010/01/07
DOI:10.1039/B921004K
Porous tubular palladium nanostructures were synthesized by electrodeposition of palladium into a CdS modified alumina template and subsequent removal of CdS; the nanostructures provided a promising platform for the fabrication of nonenzymatic glucose sensors.
Co-reporter:Yunxia Liu, Ling Si, Xiaosi Zhou, Xia Liu, Yan Xu, Jianchun Bao and Zhihui Dai
Journal of Materials Chemistry A 2014 - vol. 2(Issue 42) pp:NaN17739-17739
Publication Date(Web):2014/09/11
DOI:10.1039/C4TA03141E
A novel selenium–carbon composite has been fabricated by embedding selenium in metal–organic framework-derived microporous carbon polyhedra. Such interconnected microporous carbon polyhedra possess a large surface area and pore volume to effectively confine Se, and suppress the dissolution of polyselenides in the electrolyte. This selenium–carbon composite shows ultrastable cycling performance when used as a cathode material for lithium–selenium batteries.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 8) pp:
Publication Date(Web):
DOI:10.1039/C3AY26541B
A sandwich-type electrochemical immunosensor for the detection of alpha-fetoprotein based on a Au–antibody nanocomposite thin film as an electrode platform which was prepared by a liquid–liquid interface method was developed.
![Benzaldehyde, 4-[(1E)-2-(4-pyridinyl)ethenyl]-](http://img.cochemist.com/ccimg/118600/118528-62-4.png)
![Benzaldehyde, 4-[(1E)-2-(4-pyridinyl)ethenyl]-](http://img.cochemist.com/ccimg/118600/118528-62-4_b.png)
