Co-reporter:Xiaowen Xu and Xiurong Yang
Chemical Communications 2014 vol. 50(Issue 7) pp:805-807
Publication Date(Web):14 Nov 2013
DOI:10.1039/C3CC47102K
Herein we report the reversion of DNA strand displacement using functional nucleic acids as toeholds.
Co-reporter:Hui Zhu;Jiao Yin;Xiaolei Wang;Hongyu Wang;Xiurong Yang
Advanced Functional Materials 2013 Volume 23( Issue 10) pp:1305-1312
Publication Date(Web):
DOI:10.1002/adfm.201201643
Abstract
Heteroatom-doped carbon (HDC) has attracted tremendous attention due to its promising application in energy conversion and storage. Herein, due to its abundance high rate of reproduction, the microorganism, Bacillus subtilis, is selected as a precursor. An effective ionothermal process is adopted to produce the HDCs. Using acid activation, the obtained sample exhibits excellent electrocatalytic activity, long-term stability, and excellent resistance to crossover effects in oxygen reduction. Additionally, the base-treated sample exhibits superior performance in capacitors to most commercially available carbon materials. Even at a high current density, a relatively high capacitance is retained, indicating a great potential for direct application in energy storage.
Co-reporter:Xiaolei Wang, Hui Zhu, Xuexia Liu and Xiurong Yang
Journal of Materials Chemistry A 2013 vol. 1(Issue 11) pp:1573-1578
Publication Date(Web):10 Jan 2013
DOI:10.1039/C3TB00005B
Artificial magnetotactic probiotics (AMPs) are developed to combine living probiotic benefits with magnetic targeting properties. Experimental investigations are carried out to study their surface nano-modification process, viability and magnetic motility behavior. Subsequent in vivo studies indicate that AMPs can be applied to inhibit different invasive pathogens, including some antibiotic-resistant strains. Compared with conventional antibiotic therapy, AMPs represent an efficient and accurate alternative treatment for dealing with microbial threats, and have the potential to minimize a wide range of adverse effects.
Co-reporter:Jian Feng, Hui Zhu and Xiurong Yang
Nanoscale 2013 vol. 5(Issue 14) pp:6318-6322
Publication Date(Web):10 Jun 2013
DOI:10.1039/C3NR00878A
A new type of doped Cd:In2S3 NC, which exhibits bright white-light emission with a QY of about 18%, synthesized by a one-pot G-doping synthesis approach is presented. The successful realization of temporal separation of nucleation doping and growth doping makes this approach a facile method to synthesize the In2S3/Cd:In2S3 core/shell nanostructure.
Co-reporter:Jia Zhang, Chuanxia Chen, Xiaowen Xu, Xiaolei Wang and Xiurong Yang
Chemical Communications 2013 vol. 49(Issue 26) pp:2691-2693
Publication Date(Web):15 Feb 2013
DOI:10.1039/C3CC38298B
We have developed a Boolean NAND logic gate for the fluorescent detection of nitrite ions by using bovine serum albumin (BSA) functionalized gold nanoclusters.
Co-reporter:Jia Zhang, Cheng Yang, Chuanxia Chen and Xiurong Yang
Analyst 2013 vol. 138(Issue 8) pp:2398-2404
Publication Date(Web):11 Feb 2013
DOI:10.1039/C3AN00080J
Contamination of food and drinking water by dangerous levels of nitrite has always been of strong concern and toxicity of this inorganic anion calls for convenient detection methods. Although some visible approaches were developed to deal with this problem, using environmentally incompatible organic reagents or functionalized nanoparticles may greatly limit their wide applications. In this article, we report a method to visibly detect nitrite in less than 1 min at room temperature. The efficacy of the method relies on a specific reaction of HNO2 with H2O2 to produce peroxynitrous acid (HOONO), which oxidizes colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to its golden yellow diimine product in seconds, with the regeneration of HNO2. Therefore, HNO2 can be regarded as a catalyst for the oxidation of TMB by H2O2. Because color visualization of the TMB–H2O2 system (system I) is dependent upon the concentration of HNO2, it offers a unique avenue for the determination of nitrite. With this method, 1 μM of nitrite could be detected by the perception of yellow color in solution and less than 0.5 μM of nitrite be quantified with a spectrophotometer. The limit of detection (LOD) was 0.1 μM (S/N = 3). More interestingly, we found that the TMB–HNO2 system (system II) could be reversibly designed to detect H2O2 and then glucose with the help of glucose oxidase. We evaluated the applicability of the TMB–HOONO platform in the determination of nitrite in drinking water and urinary glucose, obtaining satisfactory results. Being sensitive, selective, time-efficient, and cost-effective, the two methods derived from the three-component reaction platform are feasible for quantification of nitrite and glucose in routine laboratory practice or rapid assay outside the laboratory.
Co-reporter:Jia Zhang and Xiurong Yang
Analyst 2013 vol. 138(Issue 2) pp:434-437
Publication Date(Web):14 Nov 2012
DOI:10.1039/C2AN36287B
We present a method for the rapid visible assay of bromate and hypochlorite in drinking water within 5 min. The assay utilizes a commercially common reagent and allows the determination of bromate and hypochlorite at several ppb levels with remarkably high selectivity over other ions.
Co-reporter:Xuexia Liu, Xiaowen Xu, Hui Zhu and Xiurong Yang
Analytical Methods 2013 vol. 5(Issue 9) pp:2298-2304
Publication Date(Web):07 Mar 2013
DOI:10.1039/C3AY26458K
Herein, we report on the production of poly(diallydimethylammonium chloride) (PDDA) functionalized reduced graphene oxide (PDDA-rGO) with the use of PDDA as a reducing and stabilizing agent. Atomic force microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the resulting PDDA-rGO nanosheets. The PDDA-rGO nanosheets could be modified with Ag nanoparticles (AgNPs) by direct adsorption of preformed, negatively charged AgNPs. It was found that the AgNPs were distributed uniformly on the PDDA-rGO nanosheets and the obtained PDDA-rGO/AgNPs nanocomposites exhibited prominent electrocatalytic activity for the detection of hydrogen peroxide (H2O2) with a wide linear range from 100 μM to 41 mM (r = 0.997) and a rapid response upon the addition of H2O2. The detection limit was estimated to be 35 μM. Furthermore, the fabricated nonenzymatic H2O2 electrochemical sensor demonstrated excellent stability and reproducibility.
Co-reporter:Fan YANG, Xiu-Rong YANG
Chinese Journal of Analytical Chemistry 2013 Volume 41(Issue 5) pp:664-669
Publication Date(Web):May 2013
DOI:10.1016/S1872-2040(13)60647-7
The kinetic analysis of interaction between tumor necrosis factor (TNF) and its two soluble extracellular receptors was carried out by using surface plasmon resonance (SPR) technique in the present study. Two immobilization strategies were used. For the first one, TNF was covalently immobilized on the CM5 sensor chip by amine coupling method, and the interaction between TNF and its soluble receptors were analyzed. For the second one, Protein A was first covalently immobilized on the CM5 sensor chip by amine coupling method, and TNF sR I/Fc Chimera or TNF sR II/Fc Chimera was subsequently captured on the sensor chip through the specific interaction of their Fc moiety with Protein A. The kinetics of immobilized soluble receptors interacted with TNF was studied by surface plasmon resonance. The experiment results showed that the kinetic parameters obtained from these two strategies agreed well. The affinity constant KD of TNF with its soluble receptors was in the magnitude of 10−9 M, indicating a higher affinity than that of the antibody-antigen interaction (KD: 10−5–10−7 M)
Co-reporter:Lixia Lu, Jia Zhang, Xiurong Yang
Sensors and Actuators B: Chemical 2013 Volume 184() pp:189-195
Publication Date(Web):31 July 2013
DOI:10.1016/j.snb.2013.04.073
By fully utilizing the strong oxidation property of hypochlorite (OCl−), we develop a facile colorimetric approach for the detection of hypochlorite with unmodified gold nanoparticles (AuNPs). This method based on the anti-aggregation of AuNPs takes advantage of the cross-linking capability of dithiothreitol (DTT). DTT could cause AuNPs to aggregate owing to the strong covalent SAu bond, with a clear color change of solution from red to blue. In the presence of hypochlorite, however, the thiol groups would readily be oxidized, and thus a red solution was observed after the subsequent addition of Au suspension owing to incapability of the oxidative derivatives of being chemisorbed on the negatively charged AuNP surface. With this colorimetric method, 2 μM of OCl− can be easily visualized by naked eye within 5 min. We applied this method to test the hypochlorite level in real water samples and satisfactory results were obtained. This sensitive and selective colorimetric assay might provide a convenient approach to detect OCl−/HOCl in various water samples.
Co-reporter:Cheng Yang, Vasilica Lates, Beatriz Prieto-Simón, Jean-Louis Marty, Xiurong Yang
Talanta 2013 Volume 116() pp:520-526
Publication Date(Web):15 November 2013
DOI:10.1016/j.talanta.2013.07.011
•Ochratoxin A, a possible human carcinogen from the mycotoxins group, was detected.•A DNAzyme–aptamer conjugate and a blocker were designed as bio-recognition element.•The unhybridized DNAzyme activity was linearly correlated with the OTA concentration.•The achieved LOD (4 nM) was suitable for OTA detection in different food samples.•A double liquid–liquid extraction method was developed to purify OTA from wine.We report a new label-free colorimetric aptasensor based on DNAzyme–aptamer conjugate for rapid and high-throughput detection of Ochratoxin A (OTA, a possible human carcinogen, group 2B) in wine. Two oligonucleotides were designed for this detection. One is N1 for biorecognition, which includes two adjacent sequences: the OTA-specific aptamer sequence and the horseradish peroxidase (HRP)-mimicking DNAzyme sequence. The other is a blocking DNA (B2), which is partially complementary to a part of the OTA aptamer and partially complementary to a part of the DNAzyme. The existence of OTA reduces the hybridization between N1 and B2. Thus, the activity of the non-hybridized DNAzyme is linearly correlated with the concentration of OTA up to 30 nM with a limit of detection of 4 nM (3σ). Meanwhile, a double liquid–liquid extraction (LLE) method is accordingly developed to purify OTA from wine. Compared with the existing HPLC-FD or immunoassay methods, the proposed strategy presents the most appropriate balance between accuracy and facility, resulting in a considerable improvement of real-time quality control, and thereby, preventing chronic poisoning caused by OTA contained red wine.
Co-reporter:Hui Zhu;Xiaolei Wang;Xuexia Liu ;Xiurong Yang
Advanced Materials 2012 Volume 24( Issue 48) pp:6524-6529
Publication Date(Web):
DOI:10.1002/adma.201202461
Co-reporter:Xiaolei Wang, Hui Zhu, Jia Zhang, Xuexia Liu, Fan Yang and Xiurong Yang
Nanoscale 2012 vol. 4(Issue 12) pp:3629-3634
Publication Date(Web):24 Apr 2012
DOI:10.1039/C2NR30766A
A selected region functionalized strategy was proposed and realized here to combine the advantages of nanotechnology and living fungi activities.
Co-reporter:Yong Wang, Yu Zheng, Fan Yang and Xiurong Yang
Chemical Communications 2012 vol. 48(Issue 23) pp:2873-2875
Publication Date(Web):06 Feb 2012
DOI:10.1039/C2CC16279B
A real-time, label-free dual polarisation interferometry technique was used to investigate the interaction of Hg2+ with a 21-mer T-rich oligonucleotide and further construct a Hg2+ biosensor based on thymine–Hg2+–thymine coordination chemistry.
Co-reporter:Jian Feng, Hui Zhu, Xiaolei Wang and Xiurong Yang
Chemical Communications 2012 vol. 48(Issue 44) pp:5452-5454
Publication Date(Web):26 Apr 2012
DOI:10.1039/C2CC31702H
This communication describes a new type of alloyed Cd–In–S quantum dots (CdIS QDs) with ultra small particle size and broadly tunable fluorescence emission from 450 to 700 nm. The band gap of CdIS QDs was mainly controlled by their composition rather than their particle size. The CdIS–ZnS core–shell nanocrystals exhibited significantly improved optical properties and chemical stabilities, with the PL quantum yield (QY) of up to 60%.
Co-reporter:Yong Wang, Juan Wang, Fan Yang, and Xiurong Yang
Analytical Chemistry 2012 Volume 84(Issue 2) pp:924
Publication Date(Web):December 8, 2011
DOI:10.1021/ac2019443
We incorporated the specific recognition of adenine-rich singled-stranded DNA (ssDNA) into dual polarization interferometry (DPI) measurements for direct, selective, and sensitive detection of the small molecule coralyne, and we simultaneously employed the real-time and label-free technique for detailed investigation of the interaction between coralyne and adenine-rich ssDNA. Data from UV–visible spectroscopy, circular dichroism (CD) spectroscopy, and DNA melting firmly confirmed that 48-mer homoadenine ssDNA oligonucleotide (A48) had highly specific recognition for coralyne, whereas 48-mer homothymine ssDNA oligonucleotide (T48) as the control had no such recognition. The immobilization of ssDNA (A48 or T48) on a silicon oxynitride chip could be achieved through a preadsorbed poly(ethylenimine) (PEI) layer. Mass, thickness, and refractive index (RI) changes resolved by DPI during the whole process of ssDNA immobilization suggested that most ssDNA molecules were likely to lie on the PEI surface mainly in the form of a flat monolayer and insert themselves partly into the PEI layer. Qualitative and quantitative analysis of mass, thickness, and RI changes in A48/PEI layer upon addition of different concentrations of coralyne revealed that A48 most likely underwent a conformational change from single-stranded to double-stranded structure. By evaluation of the binding curves from changes in mass, the association rate constant (ka), dissociation rate constant (kd), and association constant (KA) between coralyne and A48 were determined to be 4.95 × 103 M–1 s–1, 0.031 s–1, and 1.6 × 105 M–1, respectively. Good linear correlations between coralyne concentrations ranging from 0.5 to 12 μM and three parameters (mass, thickness, and RI) resolved by the response to coralyne binding were obtained. The detection limits were 0.22 μM for mass calibration, 0.14 μM for thickness calibration, and 0.32 μM for RI calibration. The high selectivity of the biosensor to coralyne at the A48/PEI interface was successfully confirmed by using the other two interfaces (T48/PEI and PEI) and three typical intercalators (ethidium bromide, daunomycin, and methylene blue). It is expected that the biosensing platform may be extended to simultaneously detect and characterize the interactions of a variety of target molecules with functional DNA molecules with high sensitivity.
Co-reporter:Yali Li, Xiurong Yang, Fan Yang, Yingping Wang, Peihua Zheng, Xiaoxu Liu
Electrochimica Acta 2012 Volume 66() pp:188-192
Publication Date(Web):1 April 2012
DOI:10.1016/j.electacta.2012.01.087
Phosphomolybdic acid anion ([PMo12O40]3−) was used for the immobilization of ruthenium(II) tris(bipyridine) (Ru(bpy)32+) on an electrode surface to yield a sensitive solid-state electrogenerated chemiluminescence (ECL) sensor. [PMo12O40]3− anion in the prepared sensor had catalytic ability to the NADH oxidation. The ECL signal of the Ru(bpy)32+/[PMo12O40]3− film was about 3-fold enhancement than that for the Ru(bpy)32+/Nafion film to NADH determination. The resulting ECL sensor exhibited a wide linear range from 2.5 × 10−7 to 5.0 × 10−3 M (R = 0.99) with the detection limit of 1.67 × 10−8 M (S/N = 3). In addition, it had good reproducibility and excellent long-term stability, and the relative average deviation was 0.77% of ECL intensity–time curve under continuous potential scanning for 21 cycles; after being used in two weeks, the sensor was able to keep over 90% activity toward 25 μM NADH. Fabrication of the ECL sensor by this method is simple and easy. Such superior properties will promote the application of polyoxometalates in fabricating sensors for using in electroanalytical and biochemical analysis.
Co-reporter:Jiying Pei, Hui Zhu, Xiaolei Wang, Hanchang Zhang, Xiurong Yang
Analytica Chimica Acta 2012 Volume 757() pp:63-68
Publication Date(Web):13 December 2012
DOI:10.1016/j.aca.2012.10.037
High-quality cysteamine-coated CdTe quantum dots (CA-CdTe QDs) were successfully synthesized in aqueous phase by a facile one-pot method. Through hydroxylamine hydrochloride-promoted kinetic growth strategy, water-soluble CA-CdTe QDs could be obtained conveniently in a conical flask by a stepwise addition of raw materials. The photoluminescence quantum yield (PL QY) of the obtained QDs reached 9.2% at the emission peak of 520 nm. The optical property and the morphology of the QDs were characterized by UV–vis absorption spectra, photoluminescence spectra (PL) and transmission electron microscopy (TEM) respectively. Furthermore, the fluorescence of the resultant QDs was quenched by copper (II) (Cu2+) and mercury (II) (Hg2+) meanwhile. It is worthy of note that to separately detect Hg2+, cyanide ion could be used to eliminate the interference of Cu2+. Under the optimal conditions, the response was linearly proportional to the logarithm of Hg2+ concentration over the range of 0.08–3.33 μM with a limit of detection (LOD) of 0.07 μM.Graphical abstractHighlights► High-quality CA-CdTe QDs were synthesized with a kinetic-growth strategy. ► The synthesis procedures were very simple. ► The obtained QDs were used to detect Hg2+ without the interference of Cu2+.
Co-reporter:Jia Zhang, Xiaowen Xu and Xiurong Yang
Analyst 2012 vol. 137(Issue 7) pp:1556-1558
Publication Date(Web):08 Feb 2012
DOI:10.1039/C2AN16307A
Colorimetric recognition and sensing of sulfide with high selectivity by virtue of glutathione-modified gold nanoparticle (GSH-AuNP) is presented. The assay is developed based on a specific anion-for-molecule ligand exchange reaction, through which sulfide replaces glutathione self-assembled on the AuNP. The unique feature of the GSH-AuNP probe makes it a novel colorimetric sensor for sulfide.
Co-reporter:Yue Yuan, Jia Zhang, Gaolin Liang and Xiurong Yang
Analyst 2012 vol. 137(Issue 8) pp:1775-1778
Publication Date(Web):12 Mar 2012
DOI:10.1039/C2AN16166D
Here we report a facile immunoassay for detecting a synthetic peptide fragment of neurogenin3 (amino acid sequence: SKQRRSRRKKANDRERNRMH) by harnessing the aggregation-dependent fluorescence property of antibody-conjugated CdTe quantum dots in the presence of the target.
Co-reporter:Jia Zhang, Xiaolei Wang and Xiurong Yang
Analyst 2012 vol. 137(Issue 12) pp:2806-2812
Publication Date(Web):25 Apr 2012
DOI:10.1039/C2AN35239G
In this article, we report a colorimetric approach for the determination of hypochlorite (OCl−) with gold nanoparticles (Au NPs). The test proceeds as two individual steps and selectivity is developed based on the strong oxidizing ability of hypochlorite. In concentrated phosphate buffer (PB), the red solution of citrate-capped Au NPs could be stabilized by the chemisorption of 11-mercaptoundecanoic acid (MUA), without which the colloidal suspension turned blue because of salt-induced particles aggregation. However, by its oxidizing power, OCl− converted the alkanethiol to a sulfonate derivative, which could not protect Au NPs from aggregation, thereby a blue solution was observed after the subsequent addition of Au suspension. With this method and under the optimal conditions (28 nm Au NP, 50 mM PB, pH 7.0, and 10 min for the colorimetric response), 1.5 μM of OCl− can be easily visualized by the naked eye. This sensitive and selective colorimetric assay opens up a fresh insight of facile, rapid, and reliable detection of OCl−, and may find its future application in the monitoring of OCl−/HOCl in waters sanitized by chlorine or hypochlorite compounds.
Co-reporter:Jia Zhang, Cheng Yang, Xiaolei Wang and Xiurong Yang
Analyst 2012 vol. 137(Issue 14) pp:3286-3292
Publication Date(Web):14 May 2012
DOI:10.1039/C2AN35204D
A colorimetric sensor for nitrite ion with high selectivity and sensitivity by unmodified citrate-capped gold nanoparticles (Au NPs) is presented. Recognition of nitrite is developed on the basis of a highly specific diazo reaction between nitrite and phenylenediamine (PDA). PDA caused the Au NPs to aggregate owing to the strong covalent NH–Au bond, with a clear color change of solution from red to blue being visualized. In the presence of phosphoric acid and nitrite, the amines of PDA would readily be converted to diazo bonds, and a red solution was observed after the subsequent addition of Au suspension due to the much less strength of electrostatic interaction between the positive diazo groups and the negative citrate-capped Au NPs. With this colorimetric “light-up” method, <1 ppm of nitrite can be easily detected within 5 min at room temperature without instrumentation. Since the diazo reaction and the colorimetric response are separate, this approach features the use of pristine Au NPs in an assay where acidic environment is a necessity, making it a more convenient and cost-effective method for the sensing of nitrite when compared with those utilizing chemically modified Au NPs.
Co-reporter:Jia Zhang, Xiaowen Xu and Xiurong Yang
Analyst 2012 vol. 137(Issue 15) pp:3437-3440
Publication Date(Web):30 May 2012
DOI:10.1039/C2AN35609K
Colorimetric recognition and sensing of sulfite by melamine-modified gold nanoparticle is reported, using Tris–HCl as the operating buffer. Furthermore, indirect determination of hypochlorite is accomplished by its oxidation of sulfite.
Co-reporter:Yue Yuan, Jia Zhang, Hanchang Zhang and Xiurong Yang
Analyst 2012 vol. 137(Issue 2) pp:496-501
Publication Date(Web):24 Nov 2011
DOI:10.1039/C1AN15875A
Neurogenin 1 (ngn1), with the functions of controlling the differentiation of neurons, determining specific neuronal subtype, and inhibiting glial differentiation, is quantitatively detected for the first time. By using specifically modified silver nanoparticles (AgNP) as the signaling element, a label-free, rapid and sensitive colorimetric immunoassay for the synthetic peptide fragment of ngn1 (amino acid sequence: AQDDEQERRRRRGRTR) is reported. The detection procedure is based on an anti-aggregation mechanism, by which ngn1 inhibits the aggregation of the probe in the presence of salt (NaClO4). The anti-ngn1 antibody conjugated AgNP (denoted as AgNP-Ab) is negatively charged, and mono-binding of the like-charged ngn1 to the probe will increase the surface charge density, hence enhancing the interparticular electrostatic repulsion. Along with the increase of ngn1 concentration, the color of the solution varies from red to yellow, thereby developing a feasible approach for the detection of ngn1. Using a UV/vis spectrophotometer, this assay exhibits a linear response range of two orders of magnitude, from 50 to 800 ng mL−1, and a detection limit of 30 ng mL−1. On the basis of these qualities, the antibody-conjugated AgNP may become a useful tool for point-of-care diagnosis of ngn1 and such a method offers a new insight on the detection of the analogous antigen fragment as well.
Co-reporter:Jia Zhang, Yue Yuan, Xiaolei Wang and Xiurong Yang
Analytical Methods 2012 vol. 4(Issue 6) pp:1616-1618
Publication Date(Web):04 Apr 2012
DOI:10.1039/C2AY25181G
A colorimetric sulfite sensor endowed with high selectivity has been developed, using melamine as the anionic binding site and gold nanoparticles as the signaling reporter.
Co-reporter:Cheng Yang, Vasilica Lates, Beatriz Prieto-Simón, Jean-Louis Marty, Xiurong Yang
Biosensors and Bioelectronics 2012 Volume 32(Issue 1) pp:208-212
Publication Date(Web):15 February 2012
DOI:10.1016/j.bios.2011.12.011
We report an aptasensor for biosensing of Ochratoxin A (OTA) using aptamer-DNAzyme hairpin as biorecognition element. The structure of this engineered nucleic acid includes the horseradish peroxidase (HRP)-mimicking DNAzyme and the OTA specific aptamer sequences. A blocking tail captures a part of these sequences in the stem region of the hairpin. In the presence of OTA, the hairpin is opened due to the formation of the aptamer–analyte complex. As a result, self-assembly of the active HRP-mimicking DNAzyme occurs. The activity of this DNAzyme is linearly correlated with OTA concentration up to 10 nM, showing a limit of detection of 2.5 nM.Highlights► Ochratoxin A, a possible human carcinogen from the mycotoxins group, was detected. ► An aptamer-DNAzyme (HRP-mimicking) hairpin was designed as bio-recognition element. ► The DNAzyme activity depends on the hairpin opening due to the OTA–aptamer complex. ► The achieved LOD (2.5 nM) is suitable for OTA detection in different food samples. ► This simple assay is a rapid (1 h for 96 samples) and cost-effective protocol.
Co-reporter:Hui Zhu;Xiaolei Wang;Fan Yang ;Xiurong Yang
Advanced Materials 2011 Volume 23( Issue 24) pp:2745-2748
Publication Date(Web):
DOI:10.1002/adma.201100901
Co-reporter:Jian Feng, Ming Sun, Fan Yang and Xiurong Yang
Chemical Communications 2011 vol. 47(Issue 22) pp:6422-6424
Publication Date(Web):09 May 2011
DOI:10.1039/C1CC11754H
A facile approach to synthesize ZnxCuyInS1.5+x+0.5y nanocrystal emitters was presented. The compositions of these nanocrystals were precisely controlled, and the relative PL quantum yields were up to 40%, with tunable emissions in 450–640 nm.
Co-reporter:Xiaowen Xu, Jia Zhang, Fan Yang and Xiurong Yang
Chemical Communications 2011 vol. 47(Issue 33) pp:9435-9437
Publication Date(Web):21 Jul 2011
DOI:10.1039/C1CC13459K
Herein we report the “OR” and “AND” colorimetric logic gates for small molecules using split/integrated aptamers and unmodified gold nanoparticles, which generate visually observed outputs according to Boolean operations.
Co-reporter:Jia Zhang, Yue Yuan, Xiaowen Xu, Xiaolei Wang, and Xiurong Yang
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 10) pp:4092
Publication Date(Web):September 26, 2011
DOI:10.1021/am200972g
Recognition and sensing of anions in aqueous media have been of considerable interest while remaining a challenging task up to date. In this document, we wish to present a simple yet sensitive method to detect inorganic anions by colorimetry based on the citrate-stabilized core/shell Cu@Ag nanoparticle (NP). It was found that the NP could discriminate some specific anions (Cl–, Br–, I–, S2–, and SCN–) from a wide range of environmentally dominant anions (F–, SO42–, H2PO4–, CO32–, NO3–, etc), identified by the change in the color of the buffered NP solution or the surface plasmon resonance (SPR) absorbance band in the UV–vis spectrum. Among the recognized anions, four types of variation in the SPR absorption band were revealed. It was strongly enhanced for Cl– and Br– and was strongly damped for S2–. For I–, it first was slightly enhanced at lower concentrations and then gradually was damped at higher concentrations. For SCN–, it first was slightly damped at lower concentrations and then was strongly enhanced at higher concentrations. In response to the optical change, the color of the NP solution turned from brown to bright yellow for Cl– (1 mM), Br– (10 μM), and SCN– (50 μM) to brownish orange for I– (10 μM) and to reddish orange for S2– (50 μM). The reason for these phenomena was postulated by the evidence of transmission electron microscope (TEM) images, X-ray photoelectron spectroscopy (XPS), and zeta potentials. In view of the importance of anions in the environment and for human health, the Cu@Ag NP colorimetric platform may have some applications, such as discriminating household table salt (NaCl) from industrial salt (NaNO2), testing the quality and extent of a variety of waters, and so forth.Keywords: anions; colorimetry; Cu@Ag nanoparticle; halides; sulfide; thiocyanate;
Co-reporter:Jia Zhang, Xiaowen Xu, Yue Yuan, Cheng Yang, and Xiurong Yang
ACS Applied Materials & Interfaces 2011 Volume 3(Issue 8) pp:2928
Publication Date(Web):July 25, 2011
DOI:10.1021/am2007678
As an extension of our previous work, which described the unique ability of the core/shell Cu@Au nanoparticle (NP) to selectively recognize iodide,(1) herein, we wish to report the development of an alternatively sensitive and selective colorimetric detection for sulfide anion and cysteine based upon the Cu@Au NP by a competition avenue. In the absence of sulfide anion or cysteine, iodide can induce an appreciable color change of the Cu@Au NP solution from purple to red by transforming the clusters of NP to single, nearly spherical, and larger ones. However, the transformation is severely interfered by the presence of sulfide or cysteine because of a higher binding strength of the S–Au bond than the I–Au one. As a result, the clear purple-to-red color change induced by iodide is affected as a correlation with the concentration of sulfide or cysteine. By taking advantage of this fact, we can detect a concentration of 3 μM for sulfide and 0.4 μM for cysteine with the naked eye or 0.3 μM (10 ppb) for sulfide and 50 nM (6 ppb) for cysteine aided by a UV/vis spectrometer. Given the detrimental effect of hydrogen sulfide and the biological importance of cysteine, the assay may become useful in the environment monitoring, water quality inspection and biomedical diagnosis as well.Keywords: anions; colorimetry; competition assay; Cu@Au nanoparticle; cysteine; sulfide;
Co-reporter:Jia Zhang, Xiaowen Xu, Cheng Yang, Fan Yang, and Xiurong Yang
Analytical Chemistry 2011 Volume 83(Issue 10) pp:3911
Publication Date(Web):March 30, 2011
DOI:10.1021/ac200480r
In the light of the significance and urgency for the recognition and sensing of anions specifically, especially those of biological relevance, herein, we wish to demonstrate a novel colorimetric avenue for highly selective iodide recognition and sensing using simple citrate-stabilized core/shell Cu@Au nanoparticles. No other ions than iodide can induce an appreciable color change of the Cu@Au nanoparticles solution from purple to red by transforming the interconnected, irregularly shaped nanoparticles to the single, separated, and nearly spherical ones, as confirmed by the transmission electron microscopy (TEM). On the basis of the optical spectra and TEM studies, a mechanism of iodide-induced aggregating/fusion, fragmentation, and reorganization of atoms is proposed. With this strategy, 6 μM (0.76 ppm) of iodide can be recognized within 20 min by naked-eye observation. This sensitive and selective colorimetric assay opens up a fresh insight of facile, rapid, and reliable detection of iodide and may find its future application in the analysis of the total iodine in edible salt as well as the clinical diagnosis of urinary iodide.
Co-reporter:Zhanxia Zhang, Xiaolei Wang and Xiurong Yang
Analyst 2011 vol. 136(Issue 23) pp:4960-4965
Publication Date(Web):03 Oct 2011
DOI:10.1039/C1AN15602K
A sensitive choline biosensor using Fe3O4 magnetic nanoparticles and a choline oxidase modified gold electrode was developed. Fe3O4 magnetic nanoparticles as peroxidase mimics used in the choline biosensor can not only improve the sensitivity of the response signal, but also possess the favorable properties of stability, magnetic separation and easy preparation, etc. When using the reduction currents of square wave voltammetry as the detection signals, the interferences of ascorbic acid and uric acid to the choline biosensor can be reduced effectively. The reduction currents of the square wave voltammetry were increased with the logarithm values of the choline chloride concentration (from 10−9 to 10−2 M), the detection limit was estimated to be 0.1 nM (S/N = 3). This choline biosensor also exhibited favorable selectivity and stability in the determination of choline chloride.
Co-reporter:Jia Zhang, Yong Wang, Xiaowen Xu and Xiurong Yang
Analyst 2011 vol. 136(Issue 19) pp:3865-3868
Publication Date(Web):10 Aug 2011
DOI:10.1039/C1AN15175D
A colorimetric probe based on 2-mercaptosuccinic acid-functionalized gold nanoparticles has been developed to exhibit selectivity towards Ca2+, Sr2+, and Ba2+ ions over other metallic cations under specified conditions and finds its practical application in detecting Ca2+ levels in water.
Co-reporter:Xiaowen Xu and Xiurong Yang
Analytical Methods 2011 vol. 3(Issue 5) pp:1056-1059
Publication Date(Web):24 Mar 2011
DOI:10.1039/C1AY05042G
We have developed a facile colorimetric glucose detection method based on an organic Fenton reaction. The color of the solution gradually turned from pale yellow to purple along with the increase of glucose concentration.
Co-reporter:Xiaolei Wang, Hui Zhu, Yi Bao, Fan Yang, and Xiurong Yang
ACS Nano 2011 Volume 5(Issue 4) pp:3250
Publication Date(Web):March 2, 2011
DOI:10.1021/nn2003794
Inspired from the ancient movable type printing, we proposed a three-dimensional tunable method for the replicable patterning of uniform patterned framework. Different sized magnetic particles were utilized as the “type-heads” for patterning. The patterning area can be precisely defined by using commercial inkjet printer. Various materials, from multicomponent inorganic structures to well-defined microporous polymers, can be readily processed by this general strategy. As a practical example, we designed and constructed an intelligent multilevel hierarchy with versatile protective capabilities.Keywords: magnetic particles; microporous polymer; patterned structure; ZnO nanoarrays
Co-reporter:Yue Yuan, Jia Zhang, Hanchang Zhang, Xiurong Yang
Biosensors and Bioelectronics 2011 Volume 26(Issue 10) pp:4245-4248
Publication Date(Web):15 June 2011
DOI:10.1016/j.bios.2011.04.021
Neurogenin3 (ngn3), as a marker for pancreatic endocrine precursor cells and an essential ingredient in the development of islet cells, was quantitatively detected for the first time. Based on a non-cross-linking specific interaction mechanism, a label-free colorimetric immunoassay for the synthetic peptide fragment of ngn3 (SKQRRSRRKKAND) using glutathione (-Glu-Cys-Gly, GSH) functionalized gold nanoparticles (GNPs) is reported. The anti-ngn3 antibody conjugated GNPs (GNP-Ab) was formed through electrostatic interaction upon the addition of anti-ngn3 antibody to the GSH-modified GNPs solution. Monobinding of the positively charged ngn3 to the negatively charged GNP-Ab will minimize the electrostatic repulsion between nanoparticles by neutralizing the surface charge, and then agglomeration is induced by an increasing salt concentration. Under the optimal conditions, the assay showed a linear response range of 50–300 ng/mL for the peptide with a detection limit being 20 ng/mL. The preliminary study on ngn3 opens up an innovative insight to detect short synthetic peptide fragment of antigen, and may own an opportunity for practical applications in clinical diagnosis and therapeutics.
Co-reporter:Yu Zheng, Yong Wang, Xiurong Yang
Sensors and Actuators B: Chemical 2011 Volume 156(Issue 1) pp:95-99
Publication Date(Web):10 August 2011
DOI:10.1016/j.snb.2011.03.077
A simple, sensitive and selective colorimetric biosensor for the detection of dopamine (DA) was demonstrated with a 58-mer dopamine-binding aptamer (DBA) as recognition element and unmodified gold nanoparticles (AuNPs) as probes. Upon the addition of DA, the conformation of DBA would change from a random coil structure to a rigid tertiary structure like a pocket and this change has been demonstrated by circular dichroism spectroscopic experiments. Besides, the conformational change of DBA could facilitate salt-induced AuNP aggregation and lead to the color change of AuNPs from red to blue. The calibration modeling showed that the analytical linear range covered from 5.4 × 10−7 M to 5.4 × 10−6 M and the corresponding limit of detection (LOD) was 3.6 × 10−7 M. Some common interferents such as 3,4-dihydroxyphenylalanine (DOPA), catechol, epinephrine (EP), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and ascorbic acid (AA) showed no or just a little interference in the determination of DA.
Co-reporter:Xuexia Liu, Hui Zhu, Xiurong Yang
Talanta 2011 Volume 87() pp:243-248
Publication Date(Web):15 December 2011
DOI:10.1016/j.talanta.2011.10.004
In this article, poly(diallydimethylammonium chloride) (PDDA) functionalized graphene-Fe3O4 (PDDA-G/Fe3O4)n multilayer films were fabricated with layer-by-layer assembly of negatively charged Fe3O4 nanoparticles (Fe3O4 NPs) and positively charged PDDA-G through the electrostatic interaction to construct a H2O2 chemical sensor. The multilayer films were characterized with UV–vis spectroscopy, atomic force microscopy and cyclic voltammetry. The participation of PDDA-G improved the catalytic ability of Fe3O4 NPs due to its high surface area and excellent electric conductivity. Based on this, the obtained H2O2 chemical sensor exhibited prominent electrocatalytic activity for the detection of H2O2 with a wide linear range from 20 μM to 6.25 mM, a rapid response upon the addition of H2O2 and a low detection limit of 2.5 μM with the signal to noise ratio of three. Furthermore, the fabricated nonenzymatic H2O2 chemical sensor exhibited excellent stability and reproducibility.Highlights► A novel H2O2 chemical sensor (PDDA-G/Fe3O4)5 multilayer films modified ITO electrode. ► Fabricated by means of the layer-by-layer assembly method. A wide linear range from 20 μM to 6.25 mM. ► Much wider than some reported biosensors based on horseradish peroxidase.
Co-reporter:Wen Yang, Yong Wang, Jing Li and Xiurong Yang
Energy & Environmental Science 2010 vol. 3(Issue 1) pp:144-149
Publication Date(Web):13 Nov 2009
DOI:10.1039/B916423E
We reported an effective and environmentally friendly method of decorating Pt nanoflowers (Pt NFs) on the surface of carbon nanotubes (CNTs). By reduction of K2PtCl4 with L-ascorbic acid in an aqueous solution, Pt nanoparticles with a flower-like morphology were deposited onto the surface of poly(sodium 4-styrenesulfonate) wrapped CNTs (PSS-CNTs). PSS plays a dual role: dispersing stable CNTs into solution in water, and providing functional groups that bind metal ions and metal nanoparticles. As-prepared Pt NFs/PSS-CNTs showed a large electroactive specific surface area, and presented excellent electrocatalytic activity for oxygen reduction. Au and Pd nanoparticles could also be deposited on PSS-CNTs. This method could be extended to the synthesis of different kinds of metal nanoparticles on other polymer wrapped CNTs. As-prepared metal nanoparticle/CNT nanocomposites could find use as electrocatalysts in polymer electrolyte membrane fuel cells.
Co-reporter:Yong Wang, Fan Yang and Xiurong Yang
ACS Applied Materials & Interfaces 2010 Volume 2(Issue 2) pp:339
Publication Date(Web):February 4, 2010
DOI:10.1021/am9007243
A sensitive and selective colorimetric detection method for mercury(II) has been well-established in this paper. It was based on the conformation change of mercury-specific oligonucleotides (MSO) from random coil structure to hairpin structure upon the addition of Hg2+ and the phenomenon of salt-induced unmodified silver nanoparticles (AgNPs) aggregation. The calibration curve showed that the net absorption ratio value at 395 and 570 nm increased linearly over the Hg2+ concentration range of 25−500 nM with a limit of detection of 17 nM. The other environmentally relevant metal ions did not interfere with the determination of Hg2+.Keywords: colorimetry; mercury(II) ion; mercury-specific oligonucleotides; thymine−Hg2+−thymine coordination; unmodified silver nanoparticles
Co-reporter:Juan Wang, Paul D. Coffey, Marcus J. Swann, Fan Yang, Jian R. Lu and Xiurong Yang
Analytical Chemistry 2010 Volume 82(Issue 13) pp:5455
Publication Date(Web):June 4, 2010
DOI:10.1021/ac9027164
We demonstrate the use of both optical extinction and phase measurements for probing the interactions between DNA and small molecules by dual polarization interferometry. On binding to DNA at the interface, mitoxantrone (MTX) and methylene blue (MB) induced reversible concentration-dependent optical extinction due to light absorption, which clearly revealed the association and dissociation of small molecules with DNA in real time. The binding constants of MTX−DNA and MB−DNA determined from the masses derived from optical extinction are 1.8 × 105 and 4.2 × 104 M−1, respectively, and shown to be buffer salt concentration-dependent. Apart from optical extinction, phase measurements reflected the overall change of the interaction; namely, a combined result of the binding of small molecules and any changes in DNA structure. The masses derived from phase could be very different from those derived from optical extinction. The structural changes detected by phase measurements showed a contraction and densification of DNA upon intercalation by MTX or MB. The combination of optical extinction and phase measurements allows a detailed understanding of the interaction process.
Co-reporter:Yali Li, Jia Zhang, Hui Zhu, Fan Yang, Xiurong Yang
Electrochimica Acta 2010 Volume 55(Issue 18) pp:5123-5128
Publication Date(Web):15 July 2010
DOI:10.1016/j.electacta.2010.04.017
Aggregates of gold nanoparticles (AuNPs) that mediate the assembly of manganese dioxide nanoparticles (nano-MnO2) for hydrogen peroxide (H2O2) amperometric sensing have been developed. The aggregates were prepared by directly mixing citric-capped AuNPs and poly(allylamine hydrochloride) (PAH)-capped nano-MnO2 using an electrostatic self-assembly strategy. The prepared sensor exhibited excellent electrochemical behaviors and a wide linear range from 7.80 × 10−7 to 8.36 × 10−4 M with a detection limit of 4.68 × 10−8 M (S/N = 3) because of the synergistic influence of excellent catalytic ability of MnO2 and good electrical conductivity of AuNPs. In addition, its applicability to practical samples for measuring H2O2 in toothpastes has obtained a satisfactory result. Due to the ease of preparation and excellent properties of the sensor, indicating the MnO2–AuNP material may be a potential H2O2 sensor.
Co-reporter:Zhanxia Zhang, Xiaolei Wang, Yong Wang and Xiurong Yang
Analyst 2010 vol. 135(Issue 11) pp:2960-2964
Publication Date(Web):08 Sep 2010
DOI:10.1039/C0AN00359J
A simple and sensitive approach for the recognition of single base mismatches in duplex DNA was developed. The single base mismatched double-strand (ds) DNA and the completely complementary dsDNA can quench the fluorescence of methylene blue to the different values, so the point mutation dsDNA can be identified from the duplex DNA effectively. The fluorescence intensity was decreased with the increasing dsDNA concentration in the range of 10∼1000 nM, the detection limit was estimated to be 50 nM (S/N = 3). The contrast experiment showed that this method possesses the universality for the distinction of other single base mismatches in duplex DNA. Moreover, the interaction mechanism between methylene blue and dsDNA was also discussed in detail. The UV-Visible absorption and the fluorescence experiments indicated that the interaction of methylene blue and dsDNA had at least two effective modes: the electrostatic binding and the intercalation binding. When more methylene blue molecules bound onto mismatched dsDNA, the fluorescence intensity of methylene blue would decrease to a lower value than that of completely complementary dsDNA. Therefore, single base mismatched dsDNA can be recognized from duplex DNA effectively.
Co-reporter:Jia Zhang, Jing Li, Fan Yang, Bailin Zhang, Xiurong Yang
Journal of Electroanalytical Chemistry 2010 Volume 638(Issue 1) pp:173-177
Publication Date(Web):5 January 2010
DOI:10.1016/j.jelechem.2009.10.019
In this communication, electroless deposition of Prussian blue (PB) on the electrode promoted by Pt nanoparticles (Ptnano) is proposed for detecting H2O2 with adjustable sensitivity. Ptnano/carbon nanotubes hybrid was initially used to modify the working electrode, followed by immersing it into the Fe3+[FeIII(CN)6] aqueous solution for electroless deposition of PB through a simple chemical reaction, which was catalyzed by Ptnano. The amount of PB deposit was controllable through varying the deposition time or the Ptnano amount on carbon nanotubes. Detection of H2O2 was successfully realized, sensitivity being dependent upon the amount of PB in the system. This work first demonstrates the feasibility of controlling the sensitivity of PB-based amperometric sensors through nanoparticles-assisted chemical deposition of PB, offering new insight into the development of electrochemical sensors using PB as the transducer.
Co-reporter:Yong Wang, Fan Yang, Xiurong Yang
Biosensors and Bioelectronics 2010 Volume 25(Issue 8) pp:1994-1998
Publication Date(Web):15 April 2010
DOI:10.1016/j.bios.2010.01.014
A colorimetric assay for the determination of mercury(II) (Hg2+) in the presence of lead(II) (Pb2+) was demonstrated with unmodified gold nanoparticles (AuNPs) as probes and 15-mer thrombin-binding aptamer (TBA, 5’-GGTTGGTGTGGTTGG-3’) as sensing elements. Upon the addition of Hg2+ or Pb2+, TBA consisting of six thymidine units and nine guanosine units interacted specifically with both ions to form a hairpin-like or a quadruplex structure, respectively. As a result, these conformation changes facilitated the salt-induced AuNP aggregation. Subsequently, to eliminate Pb2+ interference in the determination of Hg2+, a novel technique by the use of a characteristic wavelength of aggregated AuNPs instead of the universal masking agent of Pb2+ (2,6-pyridinedicarboxylic acid, PDCA) was herein proposed. A comparison of the absorption spectra of the aggregated AuNPs in the presence of Hg2+ and Pb2+ showed that the characteristic wavelength of the aggregated AuNPs (800 nm) facilitated the determination of Hg2+ in the presence of Pb2+. The calibration curve showed that the absorbance value at 800 nm increased linearly over the Hg2+ concentration range of 0.39–8.89 μM with a limit of detection of 200 nM. Then, the assay was successfully employed to determine Hg2+ in several water samples.
Co-reporter:Zhanxia Zhang, Juan Wang, Xiaolei Wang, Yong Wang, Xiurong Yang
Talanta 2010 Volume 82(Issue 2) pp:483-487
Publication Date(Web):15 July 2010
DOI:10.1016/j.talanta.2010.04.061
A sensitive biosensor with supramolecular architecture was designed and implemented here to detect choline. Choline oxidase and horseradish peroxidase were assembled onto the polymer of thiolated β-cyclodextrin and platinum nanoparticles modified gold electrode through 1-adamantane carboxylic acid coupling. Square wave voltammetry showed that the reduction currents at 0.38 mV had a linear relationship with the logarithms of choline concentrations in the range of 10−9–10−2 M, and the detection limit was down to 0.1 nM. Such biosensor also exhibited excellent selectivity, reproducibility and stability.
Co-reporter:Zhanxia Zhang, Zhongjun Wang, Xiaolei Wang, Xiurong Yang
Sensors and Actuators B: Chemical 2010 Volume 147(Issue 2) pp:428-433
Publication Date(Web):3 June 2010
DOI:10.1016/j.snb.2010.02.013
Employed as a peroxidase mimic, chitosan modified Fe3O4 magnetic nanoparticles (MNPs) were synthesized via solvothermal method. This alternative model evidenced a remarkable catalytic activity in presence of hydrogen peroxide/3,3′,5,5′-tetramethylbenzidine (TMB) solution. Fe3O4 peroxidase mimic has the merits of stability, magnetic separation and enrichment. Enzyme-linked immunosorbent assay (ELISA) was used to detect thrombin by employing the catalytic properties of the as-synthesized chitosan modified Fe3O4 MNPs. The results showed that the absorption values at 652 nm increased with the thrombin concentrations, a linear range from 1 to 100 nM and 1 nM thrombin (S/N = 3) could be detected. The proposed approach confirmed that the Fe3O4 MNPs not only possessed peroxidase activity but also showed potential application in varieties of simple, robust, and cost-effective analytical methods in the future.
Co-reporter:Xiaolong Xu, Jianbo Jia, Xiurong Yang and Shaojun Dong
Langmuir 2010 Volume 26(Issue 10) pp:7627-7631
Publication Date(Web):January 25, 2010
DOI:10.1021/la904245q
A templateless, surfactantless, simple electrochemical route to prepare dendritic gold nanostructure is reported. The morphology, composition, and structure of as-prepared dendritic gold nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The whole nanostructure was constructed by pristine metallic gold. The formation mechanism related to experimental conditions was discussed. The synthesis promises indium tin oxide (ITO) electrode can be easily modified with the dendritic pristine gold nanostructure. The as-prepared modified ITO electrode has excellent catalytic activity to oxygen reduction in neutral KCl solution.
Co-reporter:Xiaolei Wang;Hui Zhu;Fan Yang;Xiurong Yang
Advanced Materials 2009 Volume 21( Issue 27) pp:2815-2818
Publication Date(Web):
DOI:10.1002/adma.200802598
Co-reporter:Hui Zhu, Xiaolei Wang, Yali Li, Zhongjun Wang, Fan Yang and Xiurong Yang
Chemical Communications 2009 (Issue 34) pp:5118-5120
Publication Date(Web):16 Jul 2009
DOI:10.1039/B907612C
We present a facile, economical microwave pyrolysis approach to synthesize fluorescent carbon nanoparticles with electrochemiluminescence properties.
Co-reporter:Juan Wang, Xiaowen Xu, Zhanxia Zhang, Fan Yang and Xiurong Yang
Analytical Chemistry 2009 Volume 81(Issue 12) pp:4914
Publication Date(Web):May 14, 2009
DOI:10.1021/ac900591k
The structural changes of genomic DNA upon interaction with small molecules have been studied in real time using dual-polarization interferometry (DPI). Native or thermally denatured DNA was immobilized on the silicon oxynitride surface via a preadsorbed poly(ethylenimine) (PEI) layer. The mass loading was similar for both types of DNA; however, native DNA formed a looser and thicker layer due to its rigidity, unlike the more flexible denatured DNA, which mixed with PEI to form a denser and thinner layer. Ethidium bromide (EtBr), a classical intercalator, induced the large thickness decrease and density increase of native DNA (double-stranded), but a slight increase in both the thickness and density of denatured DNA (partial single-stranded). Spermine that electrostatically binds DNA induced the increase in layer thickness and decrease in the density of both native and denatured DNA. However, the looser structure of native DNA made it more accessible to spermine, leading to a higher binding amount and larger thickness increase. For native DNA, EtBr induced a slow and less reversible contraction of DNA owing to intercalation, while spermine induced a fast and reversible expansion of DNA owing to electrostatic interaction. DPI offers an effective means for real-time study of DNA structural changes during the interactions.
Co-reporter:Yali Li, Fan Yang and Xiurong Yang
Analyst 2009 vol. 134(Issue 10) pp:2100-2105
Publication Date(Web):05 Aug 2009
DOI:10.1039/B903434J
A novel Ruthenium(II) tris(bipyridine)-based solid-state electrochemiluminescence (ECL) sensor was developed in this paper. The sensor was fabricated by immobilising tris(2,2′-bipyridyl) ruthenium(II) (Ru(bpy)32+) in sulfonic-functionalised porous titania (TiO2–SO3H) nanoparticlesvia an ion exchange strategy, followed by employing environment friendly and stable biopolymer chitosan (CHIT) to entrap Ru(bpy)32+/TiO2–SO3H onto the ITO electrode. The prepared ECL sensor exhibited excellent ECL behaviors and a wide linear range from 7.5 × 10−9 to 2.5 × 10−3 M (R = 0.98) with a detection limit of 1.67 × 10−10 M (S/N = 3) towards 2-(dibutylamino)-ethanol (DBAE) detection. In addition, it had good reproducibility, and the relative average deviation was 0.95% of ECL intensity-time curve under continuous potential scanning for 34 cycles. It also had good long-term stability for the DBAE detection. After being used in three weeks, the sensor was able to keep over 80% activity towards 2.5 × 10−4 M of DBAE. Fabrication of the ECL sensor by this method is simple and easy, and hence has potential applications in ECL analysis and detection.
Co-reporter:Ai-Xue LI, Xiao-Qiang CUI, Fan YANG, Xiu-Rong YANG
Chinese Journal of Analytical Chemistry 2009 Volume 37(Issue 1) pp:25-29
Publication Date(Web):January 2009
DOI:10.1016/S1872-2040(08)60080-8
Actin is a ubiquitous cytoskeletal protein involved in many fundamental cellular processes. In a cell, actin generally performs its functions in its polymerized form (F-actin). It is well known that the interior membrane of the natural membranes contains a large amount of negatively charged lipids, so the study of the interaction between F-actin and negatively charged lipids would bring some insight on the interaction between the cytoskeleton and the cell membrane in vivo. The interaction of F-actin and negatively charged lipids membrane has been investigated by surface plasmon resonance and electrochemical impedance spectroscopy. The result shows that F-actin can interact with the negatively charged lipids membrane directly without any intermediate linker protein. Ca2+ can effectively promote this interaction, indicating that in this case, the divalent cations played an important role. High concentrations of KCl will inhibit this interaction significantly, indicating that the interaction between F-actin and negatively charged lipid membrane is mainly dominated by electrostatic interactions, although other forces also involved. The results indicate that two mechanisms of the interaction between F-actin and the lipids membrane may exist: direct interaction with lipids and interaction through other membrane protein.
Co-reporter:Xiaowen Xu, Juan Wang, Kui Jiao, Xiurong Yang
Biosensors and Bioelectronics 2009 Volume 24(Issue 10) pp:3153-3158
Publication Date(Web):15 June 2009
DOI:10.1016/j.bios.2009.03.025
Here, we report a simple and sensitive colorimetric detection method for Hg2+ ions with a tunable detection range based on DNA oligonucleotides and unmodified gold nanoparticles (DNA/AuNPs) sensing system. Complementary DNA strands with T–T mismatches could effectively protect AuNPs from salt-induced aggregation. While in the presence of Hg2+ ions T–Hg2+–T coordination chemistry leads to the formation of DNA duplexes, and AuNPs are less well protected thus aggregate at the same salt concentration, accompanying by color change from red to blue. By rationally varying the number of T–T mismatches in DNA oligonucleotides, the detection range could be tuned. Employing duplex oligonucleotides with 4 T–T mismatches in the sensing system, a sensitive linear range for Hg2+ ions from 0 to 5 μM and a detection limit of 0.5 μM are obtained. Adding the number of T–T mismatches to 6 and 8, the assay region is enlarged and linear range is tuned. A low proportion of T–T mismatches makes the detection range narrow but the sensitivity high while a high proportion influences the detection limit but enlarges assay region. Besides, the sensor also shows a good selectivity for Hg2+.
Co-reporter:Juan Wang, Xiurong Yang
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2009 Volume 74(Issue 2) pp:421-426
Publication Date(Web):1 October 2009
DOI:10.1016/j.saa.2009.06.038
It is noteworthy to understand the details of interactions between antitumor drugs and DNA because the binding modes and affinities affect their antitumor activities. Here, The interaction of toluidine blue (TB), a potential antitumor drug for photodynamic therapy of tumor, with calf thymus DNA (ctDNA) was explored by UV–vis, fluorescence, circular dichroism (CD) spectroscopy, UV-melting method and surface-enhance Raman spectroscopy (SERS). The experimental results suggest that TB could bind to ctDNA via both electrostatic interaction and partial intercalation. The fluorescence quenching of TB by ctDNA was static and due to electron transfer from bases to the excited singlet state of TB. At low [TB]/[DNA] ratio, TB mainly partially intercalated into ctDNA resulting in the slight increase of base stacking degree; at high [TB]/[DNA] ratio, excessive TB externally stacked along the helix surface via coupling with partially intercalated ones, thereby inducing B-A transition of ctDNA. The conformational transition of DNA was confirmed by the obvious improvement of the thermal stability of ctDNA. The SERS spectra suggest that TB could partially intercalate into DNA basepairs with its ring C1NC1′ side buried.
Co-reporter:Zhongjun Wang, Lei Qian, Xiaolei Wang, Hui Zhu, Fan Yang, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 Volume 332(2–3) pp:164-171
Publication Date(Web):15 January 2009
DOI:10.1016/j.colsurfa.2008.09.016
Hollow deoxyribonucleic acid (DNA)/poly-l-lysine (PLL) capsules were successfully fabricated through a layer-by-layer (LbL) self-assembly of DNA and PLL on porous CaCO3 microparticles, followed by removal of templates with ethylenediamine tetraacetic acid disodium salt (EDTA). The enzymatic degradation of the capsules in the presence of α-chymotrypsin was explored. The higher the enzyme concentration, the higher is the degradation rate of hollow capsules. In addition, glutaric dialdehyde (GA) cross-linking was found to be another way to manipulate degradation rate of hollow capsules. DNA/PLL capsules with a higher GA cross-linking density degraded at a lower rate. Dextran, as a model drug, was then encapsulated into DNA/PLL microcapsules via spontaneous deposition mechanism, and the loading process was observed by the confocal microscope using fluorescence labeled dextran. This capsule system showed a high loading capacity for Dextran. The resultant capsules were then used as dual carriers for DNA and dextran by enzymatic degradation, and they could effectively discharge drug payloads. This dual carrier system is expected to find applications in biomedical fields owing to their good biocompatibility and high transport efficiency of drug, and utilization of the cooperative effect of DNA and non-gene drug.
Co-reporter:Zhongjun Wang, Hui Zhu, Wen Yang, Xiaolei Wang, Juan Wang, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 Volume 348(1–3) pp:137-144
Publication Date(Web):20 September 2009
DOI:10.1016/j.colsurfa.2009.07.008
Dextran sulfate (DS)/poly-l-lysine (PLL) microcapsules are fabricated by an in situ coacervation method using DS-doped CaCO3 microparticles as templates. Twinned superstructures or spherical CaCO3 microparticles are produced depending on DS concentration in the starting solution. DS/PLL microcapsules with ellipsoidal or spherical outline are obtained after removal of templates in disodium ethylene diamine tetraacetate dehydrate (EDTA) without PLL. Their shell thickness and negative surface charges increase with the DS weight percentage in the templates. The surface potential of DS/PLL microcapsules, fabricated by core removal in an EDTA/PLL solution, can be easily tuned by altering PLL concentration in template removal solution. DS/PLL microcapsules fabricated by template removal in solution with or without PLL are both degraded by α-chymotrypsin, and different degradation profiles are observed because of shell thickness differences. DS/PLL may be used as transport vehicles for various compounds regardless of their charge sign in biomedical fields.
Co-reporter:Wen Yang, Cheng Yang, Ming Sun, Fan Yang, Ying Ma, Zhanxia Zhang, Xiurong Yang
Talanta 2009 Volume 78(Issue 2) pp:557-564
Publication Date(Web):30 April 2009
DOI:10.1016/j.talanta.2008.12.009
We reported a simple and effective green chemistry route for facile synthesis of nanowire-like Pt nanostructures at one step. In the reaction, dextran acted as a reductive agent as well as a protective agent for the synthesis of Pt nanostructures. Simple mixing of precursor aqueous solutions of dextran and K2PtCl4 at 80 °C could result in spontaneous formation of the Pt nanostructures. Optimization of the experiment condition could yield nanowire-like Pt nanostructures at 23:1 molar ratio of the dextran repeat unit to K2PtCl4. Transmission electron microscopy results revealed that as-prepared nanowire-like Pt nanostructures consisted of individual Pt nanoparticles with the size range from 1.7 to 2.5 nm. Dynamic light scattering analysis indicated that as-prepared nanowire-like nanostructures have already formed in solution. The as-prepared nanowire-like Pt nanostructures were further characterized by UV–vis spectroscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. In addition, the ratio dependence and temperature dependence of this reaction have also been investigated. The as-prepared nanowire-like Pt nanostructures can be immobilized on glassy carbon electrodes using an electrochemical coupling strategy, and the resulting nanowire-like Pt nanostructures modified film exhibited an excellent electrocatalytic activity for the reduction of oxygen and the oxidation of NADH.
Co-reporter:Zhanxia Zhang, Wen Yang, Juan Wang, Cheng Yang, Fan Yang, Xiurong Yang
Talanta 2009 Volume 78(4–5) pp:1240-1245
Publication Date(Web):15 June 2009
DOI:10.1016/j.talanta.2009.01.034
A label-free and highly sensitive impedimetric aptasensor based on a polyamidoamine dendrimer modified gold electrode was developed for the determination of thrombin. Amino-terminated polyamidoamine dendrimer was firstly covalently attached to the cysteine functionalized gold electrode through glutaraldehyde coupling. Subsequently, the dendrimer was activated with glutaraldehyde, and amino-modified thrombin aptamer probe was immobilized onto the activated dendrimer monolayer film. The layer-by-layer assembly process was traced by surface plasmon resonance and electrochemical impedance spectroscopy. After electrode preparation, the detection of thrombin was investigated in the presence of the reversible [Fe(CN)6]3−/4− redox couple using impedance technique. The results showed that the charge-transfer resistance (Rct) value had a linear relationship with the concentrations of thrombin in the range of 1–50 nM, and the detection limit (S/N = 3) as low as 0.01 nM was obtained. The covalent immobilization of dendrimer on the electrode surface not only improved the immobilization capacity of probe molecules but also magnified the response signal. The aptasensor exhibited favorable regeneration ability, selectivity and stability. It also showed the detectability in biological fluid.
Co-reporter:Jia Zhang, Jing Li, Fan Yang, Bailin Zhang, Xiurong Yang
Sensors and Actuators B: Chemical 2009 Volume 143(Issue 1) pp:373-380
Publication Date(Web):4 December 2009
DOI:10.1016/j.snb.2009.08.018
In this study, the fabrication of an efficient amperometric hydrogen peroxide sensor with favorable properties is presented. Prussian blue (PB) was catalytically synthesized by Pt nanoparticles (Ptnano) from ferric ferricyanide aqueous solution to form PB@Ptnano hybrid, and it was confirmed by transmission electron microscope (TEM) and optical spectra. The electrochemical behavior of PB@Ptnano was highly improved through its integration with poly(diallyldimethylammonium chloride) modified carbon nanotubes (PCNTs). The obtained PB@Ptnano/PCNTs composite was used to modify the glassy carbon (GC) electrode, developing an electrochemical sensor for detecting H2O2. In the optimized operational conditions (E = 0.1 V, pH 2.0), the response time and detection limit (S/N = 3) of this sensor were determined to be below 2 s and 0.15 μM, respectively. Compared with the PB@Ptnano sensing system, the determination by the PB@Ptnano/PCNTs sensor was much more improved, with a wider linear range, a lower limit of detection, and a higher sensitivity. Interference study and operational stability of the sensor were investigated, meanwhile, influence of the amount of PB@Ptnano upon the sensor sensitivity was also discussed.
Co-reporter:Jing Li, Wen Yang, Hui Zhu, Xiaolei Wang, Fan Yang, Bailin Zhang, Xiurong Yang
Talanta 2009 Volume 79(Issue 3) pp:935-939
Publication Date(Web):15 August 2009
DOI:10.1016/j.talanta.2009.05.029
Co-reporter:Yali Li, Hui Zhu, Xiurong Yang
Talanta 2009 Volume 80(Issue 2) pp:870-874
Publication Date(Web):15 December 2009
DOI:10.1016/j.talanta.2009.08.008
In order to solidify the electrochemiluminescence (ECL) luminophor tris(2,2′-bipyridyl) ruthenium(II) ([Ru(bpy)3]2+) onto the electrode surfaces robustly, the negative charged heteropolyacids (HPAs) moieties were utilized to attract and bond cations [Ru(bpy)3]2+ via an adsorption method. The compositions and microstructures of the hybrid complexes were characterized by elemental analysis (EDS), spectroscopic techniques (UV–vis, FTIR) and field-emission scanning electron microscopy (FE-SEM). The electrochemical and ECL behaviors of the [Ru(bpy)3]2+/[PW12O40]3− hybrid complex contained in the solid film of the nanocomposites formed on the electrode surfaces were also studied. It was found that the corresponding solid membranes exhibited a diffusion-controlled voltammetric feature and excellent electrochemiluminescence behaviors. Hence potential prospects as new electrochemiluminescent materials for application in electroanalytical detection are envisioned.
Co-reporter:Ming Sun and Xiurong Yang
The Journal of Physical Chemistry C 2009 Volume 113(Issue 20) pp:8701-8709
Publication Date(Web):April 24, 2009
DOI:10.1021/jp811308h
CdSe nanocrystals (NCs) are prepared in noncoordination solvents (1-octadecene (ODE) and paraffin liquid) with long-chain primary alkylamine as the sole ligand, ODE-Se, and cadmium fatty acid salt as precursors. The obtained NCs meet the four fundamental parameters for high-quality NCs: high crystallinity, narrow size distribution, moderate photoluminescence quantum yield, and broad range size tunableness. Further, by simply regulating the relative molar ratio of alkylamine to cadmium precursor, the regular sized “nuclei” and final obtained NCs can be produced predictably within a certain size range. The size distribution of regular sized “nuclei” is very narrow (fwhm = 23 ± 1 nm), and the following focusing growth procedure vanishes. This indicates a different nucleation and growth kinetics from that of the well-established “focusing” and “defocusing” theory. By analyzing the conversion factor of precursors and the concentration of magic sized nanoclusters and regular sized “nuclei”, a subtle secondary nucleation mechanism, “quantized fusion”, was proposed. First, magic sized nanoclusters are formed as the critical nuclei; second, quantized critical nuclei will couple together and fuse into perfect regular sized “nuclei” by combining with stoichiometric monomers. The “quantized fusion” transformation could be regulated by the nature and ratios of the “activating agent” and the “nucleating agent”. These transition processes are very rapid and should be kinetically controlled. The molecular mechanism for monomer formation may be based on the traditional ester aminolysis reaction.
Co-reporter:Hui Zhu, Xiaolei Wang, Wen Yang, Fan Yang, Xiurong Yang
Materials Research Bulletin 2009 44(10) pp: 2033-2039
Publication Date(Web):
DOI:10.1016/j.materresbull.2009.05.023
Co-reporter:Xiaolei Wang;Hui Zhu;Zhongjun Wang;Fan Yang Dr. ;Xiurong Yang
Chemistry - A European Journal 2009 Volume 15( Issue 43) pp:11473-11477
Publication Date(Web):
DOI:10.1002/chem.200902315
Co-reporter:Xiaolei Wang;Hui Zhu;Wen Yang;Fan Yang Dr.;Xiurong Yang
Chemistry - A European Journal 2009 Volume 15( Issue 17) pp:4253-4257
Publication Date(Web):
DOI:10.1002/chem.200900003
Co-reporter:Ming Sun, Haizhou Yu, Wen Yang, Li Qi, Fan Yang, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 350(1–3) pp: 91-100
Publication Date(Web):
DOI:10.1016/j.colsurfa.2009.09.010
Co-reporter:Wen Yang;Xiaolei Wang;Fan Yang;Cheng Yang;Xiurong Yang
Advanced Materials 2008 Volume 20( Issue 13) pp:2579-2587
Publication Date(Web):
DOI:10.1002/adma.200702949
Co-reporter:Lei Qian, Xiurong Yang
Analytica Chimica Acta 2008 Volume 609(Issue 2) pp:210-214
Publication Date(Web):25 February 2008
DOI:10.1016/j.aca.2007.12.039
A novel method for immobilization of tris(2,2′-bipyridyl)ruthenium(II) (Ru(bpy)3Cl2) on electrode surfaces based on the vapor-surface sol–gel deposition strategy is first demonstrated in this paper. Ru(bpy)3Cl2 immobilized sol–gel (Ru(bpy)3Cl2/sol–gel) films were characterized by UV–vis spectroscopy and field-emitted scanning electron microscopy (FE-SEM). These results showed that Ru(bpy)3Cl2 was successfully incorporated into the silica sol–gel film. It was found that many irregular Ru(bpy)3Cl2/sol–gel clusters were formed on surfaces through one deposition and thick sol–gel films were observed after further deposition. Electrochemical properties and electrochemiluminescence (ECL) behaviors of Ru(bpy)3Cl2/sol–gel films could be easily adjusted by deposition numbers and time. At last, the Ru(bpy)3Cl2/sol–gel film modified electrode was used for solid-state ECL detection of tripropylamine. The linear range was from 5.8 × 10−8 to 2.4 × 10−4 M with the detection limit of 5 nM, which was three orders of magnitude lower than that from pure Nafion-modified electrodes. The ECL sensor also exhibited high stability, and still remained 92% response after being stored in air for 35 days. This method for immobilization of Ru(bpy)3Cl2 is simple, convenient and low-cost relative to others, so it shows promising applications in solid-state ECL detection.
Co-reporter:Hui Zhu, Xiaolei Wang, Fan Yang and Xiurong Yang
Crystal Growth & Design 2008 Volume 8(Issue 3) pp:950
Publication Date(Web):February 6, 2008
DOI:10.1021/cg700850e
In this work, a one-dimensional microrod-based three-dimensional flowerlike indium hydroxide (In(OH)3) structure was fabricated, without any templates or surfactants, using a well-known hydrothermal approach at a non-high temperature. In2O3 with similar morphology was formed by annealing In(OH)3 precursors and was characterized by Raman spectrum and photoluminescence (PL) spectrum in detail. The properties of the obtained In(OH)3 composites were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and thermogravimetric analysis. The effects of the experimental parameters such as the alkaline source selection, the concentration of urea, and the temperature on the morphology are discussed. These results indicate that the aligned superstructure originated from the oriented attachment of small particles.
Co-reporter:Yang Liu, Xiaolei Wang, Fan Yang, Xiurong Yang
Microporous and Mesoporous Materials 2008 Volume 114(1–3) pp:431-439
Publication Date(Web):1 September 2008
DOI:10.1016/j.micromeso.2008.01.032
Optically transparent, crack-free, mesoporous anatase TiO2 thin films were fabricated. The Ag/TiO2 composite films were prepared by incorporating Ag in the pores of TiO2 films with an impregnation method via photoreduction. The as-prepared composite films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectronic spectra (XPS) and N2 adsorption. The release behavior of silver ions in the mesoporous composite film was also studied. Moreover, the antimicrobial behaviors of the mesoporous film were also investigated by confocal laser scanning microscopy. The antibacterial activities of the composite films were studied by a fluorescence label method using Escherichia coli (E. coli) as a model. The as-prepared mesoporous TiO2 films showed much higher antimicrobial efficiency than that of glass and commercial P25 TiO2 spinning film. The facts would result from the high surface area, small crystal size and more active sites for the mesoporous catalysis. After the doping of Ag, a significant improvement for the antimicrobial ability was obtained. To elucidate the roles of the membrane photocatalyst and the doped silver in the antimicrobial activity, cells from a silver-resistant E. coli were used. These results indicated that Ag nanoparticles in the mesoporous were not only an antimicrobial but also an intensifier for photocatalysis. The as-prepared mesoporous composite film is promising in application of photocatalysis, antimicrobial and self-clean technologies.
Co-reporter:Bin Qi, Xiurong Yang
Materials Letters 2008 Volume 62(6–7) pp:980-983
Publication Date(Web):15 March 2008
DOI:10.1016/j.matlet.2007.07.032
A fullerene/ionic-liquid composite was explored. Transmission Electron Microscopy (TEM) study showed that in the composite, C60 mainly exists as nano-clusters, Raman spectrum proved that the composite formed only by physical mix of C60 and 1-Butyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6), the combination did not change the chemical naturation of C60. The electrochemical properties of the composite modified electrode, including the electrode reaction control function and the interfacial potential effect were studied. The results showed the electrode reaction is controlled by the diffusion and the interfacial potential can be ignored on the modified electrode. At the same time, the composite was found electrocatalytic property in the electrochemical oxidation of dihydronicotinamide adenine dinucleotide (NADH).
Co-reporter:Lei Qian, Xiurong Yang
Talanta 2008 Volume 74(Issue 5) pp:1649-1653
Publication Date(Web):15 February 2008
DOI:10.1016/j.talanta.2007.10.042
Electrodeposition of novel Au/Pd bimetallic nanostructures with dendrimer films as matrices has been reported. The dendrimers exhibited highly open structures arising from protonation of amines and this made them have good penetrability for solvent molecules. The unique properties of dendrimers obviously affected the morphologies and compositions of deposited bimetallic nanostructures compared with those from unmodified surfaces. Field-emitted scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy and UV–vis spectroscopy were used to characterize these nanostructures. The results showed that these bimetallic nanostructures were consisted of many small nanoparticles. Effects of ratios of KAuCl4 and K2PdCl6, electrodeposition time and layer number of assembled dendrimers were thoroughly investigated. At last, electrochemical properties of the bimetallic nanostructures were also studied.
Co-reporter:Haixin Bai;Cheng Yang;Xiurong Yang
Frontiers of Chemistry in China 2008 Volume 3( Issue 1) pp:105-111
Publication Date(Web):2008 January
DOI:10.1007/s11458-008-0013-4
This work attempts to calculate the binding-site number using fluorescence spectroscopic method with bovine serum albumin (BSA) and Indo-1 as protein and ligand models, respectively. The method for calculating the binding-site number in BSA for Indo-1 was developed based on the relationships between changes in Indo-1 fluorescence intensity and the analytical concentration of BSA. The interaction between BSA with Indo-1 was investigated comprehensively using fluorescence techniques as well as fluorescence resonance energy transfer, and the thermodynamic parameters were calculated according to the effect of enthalpy on temperature. Three binding sites in BSA for Indo-1 were revealed, and the distances from Trp212 in BSA to the three binding sites were 2.93, 2.57 and 2.40 nm, respectively. It was also proven that Indo-1 embedded into the three hydrophobic cavities of BSA by hydrophobic association. This paper provides a reference on calculating the binding-site number in proteins for ligands and studying their interactions by fluorescence spectroscopic methods. In fluorescent quenching experiments, fluorescence changes were automatically recorded in real time by combining the Microlab 500 Series Dispenser and PTI fluorescence apparatus.
Co-reporter:Fan Yang;Xiurong Yang
Frontiers of Chemistry in China 2008 Volume 3( Issue 1) pp:14-17
Publication Date(Web):2008 January
DOI:10.1007/s11458-008-0005-4
Lipopolysaccharide (LPS) is a major component of the outer membrane of all gram-negative bacteria. It interacts with some biomolecules and triggers a toxic reaction. In this paper, we studied the interaction between LPS from Salmonella Minnesota and some biomolecules using a surface plasmon resonance (SPR) biosensor. Biomolecules were immobilized on a CM5 sensor chip using the amino coupling method and LPS was injected over the immobilized surfaces. The affinity constant KA of LPS with serum albumin, hemoglobin, chitosan and lysozyme was 2.36 × 107, 2.03 × 108, 7.58 × 106, 2.82 × 104 L·mol−1, respectively. However, LPS could not interact with ferritin.
Co-reporter:Hui Zhu ; Xiaolei Wang ; Zhongjun Wang ; Cheng Yang ; Fan Yang ;Xiurong Yang
The Journal of Physical Chemistry C 2008 Volume 112(Issue 39) pp:15285-15292
Publication Date(Web):September 6, 2008
DOI:10.1021/jp804768w
Using sodium dodecyl sulfate (SDS), a 3D microflowery indium hydroxide [In(OH)3] structure assembled from 2D nanoflakes was fabricated in a large quantity via a hydrothermal approach at relative low temperature. The obtained In(OH)3 flowers exhibited a narrow size range between 4 and 6 μm. The properties of these composites were characterized by XRD, EDX, FE-SEM, TEM, SAED, and TGA. In this work, both the use of urea and SDS and the amounts of these components played important roles in the formation of In(OH)3 with different nanostructures. A surfactant-assisted 3D self-assembly and transformation mechanism was inferred from the evolution of the morphology to elucidate the formation of these flowery structures. In addition, In2O3 with a similar morphology could be formed by annealing In(OH)3 precursors. Furthermore, potentialities of the flowery In2O3 were indicated in detail by N2 adsorption−desorption isotherm characterization and a photoluminescence (PL) spectroscopy investigation.
Co-reporter:Yang Liu, Fan Yang, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2008 Volume 312(2–3) pp:219-225
Publication Date(Web):15 January 2008
DOI:10.1016/j.colsurfa.2007.06.054
By using ethylenediamine as both an alkali and ligand, quantum size SnO2 nanocrystallites were synthesized with a solvothermal route. The transmission electron micrographs (TEM) were employed to characterize the morphologies of the products. The crystal sizes of the as-synthesized SnO2 were ranged form 2.5 to 3.6 nm. The crystal structure and optical properties of the products were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, optical absorption spectra, photoluminescence and Raman spectra. Anisotropic growth of the SnO2 nanocrystallites was observed by altering the solvent from water to ethanol. The SnO2 nanocrystal showed apparent quantum confinement effects. Finally, the mechanism for the formation of quantum size SnO2 was also discussed.
Co-reporter:Lei Qian, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2008 Volume 317(1–3) pp:528-534
Publication Date(Web):20 March 2008
DOI:10.1016/j.colsurfa.2007.11.049
Electrodeposition of silver nanostructures on a polyamidoamine (PAMAM) dendrimers-modified surface has been reported. The assembled PAMAM monolayer film was used as a substrate for electrodeposition. We found that the PAMAM dendrimers obviously affected nucleation growth and silver nanostructures (spherical, dendritic and “fish bone” shapes) were obtained, which were different from those deposited on unmodified surfaces. It was attributed to the unique structures and properties of PAMAM dendrimers compared with linear polymers. Field-emitted scanning electron microscopy, energy-dispersive spectroscopy and X-ray photoelectron spectroscopy were used to characterize the deposited nanostructures. The effects of electrodeposition potential and time, Ag+ concentration, and the electrolyte were carefully investigated and studied. These results showed that PAMAM dendrimers could be used as “controllers” for modulation of deposited silver nanostructures.
Co-reporter:Zhongjun Wang, Lei Qian, Xiaolei Wang, Fan Yang, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2008 Volume 326(1–2) pp:29-36
Publication Date(Web):15 August 2008
DOI:10.1016/j.colsurfa.2008.05.010
DNA/poly-L-lysine (PLL) capsules were constructed through a layer-by-layer (LbL) self-assembly of DNA and PLL on CaCO3 microparticles, and then used as dual carriers for DNA and drug after dissolution of carbonate cores. The permeability of DNA/PLL microcapsules was investigated with fluorescence probes with different molecular weights by confocal microscopy. The result revealed that the fluorescence probes were able to penetrate the capsule walls even its molecular weight up to 150 kDa. The resultant capsules were used to load drug model molecules-fluorescein isothiocyanate (FITC)–dextran (4 kDa) via spontaneous deposition mechanism. DNA/PLL capsules were used as dual drug carriers for concurrent delivery DNA and FITC–dextran molecules by salt-triggered capsule decomposition. The amount of released DNA and drug can be controlled by adjusting ionic strength. The larger salt concentration, the more DNA and drug were released. Two remedial agents could be simultaneously introduced to the diseased region by using this carrier system, which may really improve curative effect due to the synergetic effect of DNA and drug.
Co-reporter:Zhongjun Wang, Hui Zhu, Dan Li, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2008 Volume 329(1–2) pp:58-66
Publication Date(Web):15 October 2008
DOI:10.1016/j.colsurfa.2008.06.050
Autofluorescent single polyelectrolyte microcapsules, exemplified by poly-l-lysine (PLL), have been prepared through glutaraldehyde-mediated covalent layer-by-layer (LbL) assembly and subsequent core removal. CaCO3 microparticles were used as template cores for the LbL deposition and removed by treatment of ethylenediamine tetraacetic acid disodium salt (EDTA). The prepared microcapsules, without conjugating an exterior fluorochrome, exhibited evenly distributed fluorescence. The fluorescence properties of PLL microcapsules were investigated by fluorescence spectroscopy and confocal laser scanning microscopy. The fluorescence color could be modulated with different excitation wavelengths. Autofluorescent PLL microcapsules were used as fluorescence tracers for cell imaging after cell ingestion. Sodium borohydride (NaBH4) reduction was also used to alter fluorescence character of PLL microcapsules.
Co-reporter:L. Qian;X.-R. Yang
Advanced Functional Materials 2007 Volume 17(Issue 8) pp:
Publication Date(Web):12 APR 2007
DOI:10.1002/adfm.200600253
One-step synthesis of Ru(bpy)3Cl2-immobilized (bpy = 2,2′-bipyridine) silica nanoparticles (Ru–silica nanoparticles) for use in electrogenerated-chemiluminescence (ECL) detection is reported. Ru–silica nanoparticles are prepared by using the Stöber method. Compared with free Ru(bpy)3Cl2, Ru–silica nanoparticles are seen to exhibit a red-shift of the UV-vis absorbance peak and a longer fluorescence lifetime, which are attributed to the electrostatic interaction of Ru(bpy)32+ and silica. Because silica nanoparticles are used as immobilization matrices, the surfaces of Ru–silica nanoparticles are easily modified or functionalized via the assembly of other nanoparticles, such as Au. For ECL detection, Au-colloid-modified Ru–silica nanoparticles are immobilized on a 3-mercaptopropyl-trimethoxysilane-modified indium tin oxide electrode surface by Au–S interaction; the surface concentration of electroactive Ru(bpy)3Cl2 is obviously higher than that in silica films. The modified electrode exhibits excellent ECL signals and gives a good linear range over 5 × 10–7–1.4 × 10–3 M with a detection limit of 50 nM towards the tripropylamine (TPA) detection. Moreover, the electrode has better reproducibility and long-term stability for the determination of TPA than electrodes modified with pure Nafion, Nafion–silica, Nafion–TiO2, or sol-gel films containing Ru(bpy)3Cl2. Immobilization of Ru(bpy)3Cl2 on the electrode surface by this method is simple and easy, so it shows potential applications in the field of ECL analysis and detection.
Co-reporter:Xiaolei Wang, Fan Yang, Wen Yang and Xiurong Yang
Chemical Communications 2007 (Issue 42) pp:4419-4421
Publication Date(Web):17 Aug 2007
DOI:10.1039/B708662H
In this study, ZnO nanowire arrays with different orientations were prepared. Confocal laser scanning microscopy (CLSM) and field-emission scanning electron microscope (FE-SEM) technique were employed for understanding the disparities in antibacterial activity between different orientations of ZnO nanoarrays. The effects of the different planes of ZnO nanowire were also discussed for the first time.
Co-reporter:Lei Qian, Xiurong Yang
Electrochemistry Communications 2007 Volume 9(Issue 3) pp:393-397
Publication Date(Web):March 2007
DOI:10.1016/j.elecom.2006.10.003
Effective enhancement of electrochemiluminescence (ECL) of peroxydisulfate on a C60/didodecyldimethyl ammonium bromide (C60/DDAB) film coated glassy carbon electrode (GCE) surface is reported in this paper. The C60/DDAB film gave lower cathodic current in the presence of peroxydisulfate than that from a bare GCE. To our surprise, electrochemiluminescent intensity from peroxydisulfate reduction was effectively enhanced on the C60/DDAB film, which was 50 times and 250 times higher than those from a DDAB film coated and bare GCE, respectively. Moreover, the ECL onset potential on the C60/DDAB film was about −0.9 V, which positively shifted 200 mV compared with that from the bare GCE. Dissolved oxygen and the applied potential also affected the electrochemiluminescent intensity. The presence of oxygen decreased the intensity, and the intensity reached maximum at the applied potential of −1.7 V. The unique property will greatly enrich ECL studies and applications based on fullerenes.
Co-reporter:Qi Bin, Zhikun Zheng, Xiurong Yang
Applied Surface Science 2007 Volume 253(Issue 10) pp:4698-4703
Publication Date(Web):15 March 2007
DOI:10.1016/j.apsusc.2006.10.028
Abstract
It was studied that the nanostructure formed on a gold surface via a simple oxidation–reduction cycles (ORC) in 0.1 M KCl containing Ru(bpy)32+ with different concentrations. Atomic force microscopy (AFM) and energy-dispersed spectroscopy (EDS) were used to characterize the nanostructure formed on the gold surface. Sweep-step voltammetry and corresponding electroluminescence (ECL) response, in situ electrochemical quartz crystal microbalance (EQCM) measurement were used to monitor the ORC procedure. It was found that the surface structure became more uniform in the presence of Ru(bpy)32+, and the surface roughness was decreasing with the increasing of Ru(bpy)32+ concentration, suggesting a simple and effective method to control the formation of nanostructure on the gold surface.
Co-reporter:Aixue Li, Ying Ma, Fan Yang, Xiurong Yang
Applied Surface Science 2007 Volume 253(Issue 14) pp:6103-6108
Publication Date(Web):15 May 2007
DOI:10.1016/j.apsusc.2007.01.013
Abstract
α-Actinin has been shown to be capable of interacting with some special membrane phospholipids directly, which is important for its function. In this study, hybrid bilayer membranes composed of negatively charged lipids are constructed on the surface plasmon resonance gold substrate and on the gold electrode, respectively, and the interaction between α-actinin and negatively charged lipids membrane is investigated by surface plasmon resonance, cyclic voltammetry and electrochemical impedance spectroscopy methods. α-Actinin is proved to be able to interact with the negatively charged lipids membrane directly. It can also insert at least partly into the membrane or lead to some defect or lesion in the membrane, which increase the permeability of the membrane. This study would bring some insight on the interaction between the α-actinin and the cell membranes in vivo.
Co-reporter:Aixue Li, Fan Yang, Ying Ma, Xiurong Yang
Biosensors and Bioelectronics 2007 Volume 22(Issue 8) pp:1716-1722
Publication Date(Web):15 March 2007
DOI:10.1016/j.bios.2006.07.033
Bioactive ultrathin films with the incorporation of amino-terminated G4 PAMAM dendrimers have been prepared via layer-by-layer self-assembly methods on a gold electrode and used for the DNA hybridization analysis. Surface plasmon resonance (SPR), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS) are used to characterize the successful construction of the multicomponent film on the gold substrate. The dendrimer-modified surfaces improve the immobilization capacity of the probe DNA greatly, compared to the AET (2-aminoethanethiol) SAM sensor surfaces without dendrimer molecules. DNA hybridization analysis is monitored by EIS. The dendrimer-based electrochemical impedance DNA biosensor shows high sensitivity and selectivity for DNA hybridization assay. The multicomponent films also display a high stability during repeated regeneration and hybridization cycles.
Co-reporter:Wen Yang, Ying Ma, Jiang Tang, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2007 Volume 302(1–3) pp:628-633
Publication Date(Web):20 July 2007
DOI:10.1016/j.colsurfa.2007.02.028
A green synthetic strategy to prepare monodisperse Pt nanoparticles was reported. Aminodextran acted as the reductive and protective agents, and Pt nanoparticles were conveniently obtained at one step. The as-prepared Pt nanoparticles were characterized by UV/vis spectroscopy (UV–vis), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). By changing the initial molar ratio of aminodextran to platinum precursor, Pt nanoparticles with different size were obtained. Amino groups of aminodextran could absorb on Pt nanoparticles surfaces and serve as a very good stabilizer. However, dextran without amino groups could not effectively stabilize Pt nanoparticles and aggregation of Pt nanoparticles were obtained. Catalytic activity of these Pt nanoparticles for the electron-transfer reaction between hexacyanoferrate (III) ions and thiosulfate ions was also studied, and they showed good catalytic efficiency.
Co-reporter:Lei Qian, Xiurong Yang
Talanta 2007 Volume 73(Issue 1) pp:189-193
Publication Date(Web):15 August 2007
DOI:10.1016/j.talanta.2007.03.016
In this paper, we demonstrate an electrochemiluminescence (ECL) enhancement of tris(2,2-bipyridyl)ruthenium(II) (Ru(bpy)32+) by the addition of silver(I) ions. The maximum enhancement factor of about 5 was obtained on a glassy carbon electrode in the absence of co-reactant. The enhancement of ECL intensity was possibly attributed to the unique catalytic activity of Ag+ for reactions between Ru(bpy)33+ with OH. The higher enhancement was observed in phosphate buffer solutions compared with that from borate buffer solutions. This resulted from the fact that formation of nanoparticles with large surface area in the phosphate buffer solution exhibited high catalytic activity. The amount of Ag+, solution pH and working electrode materials played important roles for the ECL enhancement. We also studied the effects of Ag+ on Ru(bpy)32+/tripropylamine and Ru(bpy)32+/C2O42− ECL systems.
Co-reporter:Haizhen Huang, Zhigang Liu, Xiurong Yang
Analytical Biochemistry 2006 Volume 356(Issue 2) pp:208-214
Publication Date(Web):15 September 2006
DOI:10.1016/j.ab.2006.05.021
Gold nanoparticles were used to enhance the immobilization amount and retain the immunoactivity of recombinant dust mite allergen Der f2 immobilized on a glassy carbon electrode (GCE). The interaction between allergen and antibody was studied by electrochemical impedance spectroscopy (EIS). Self-assembled Au colloid layer (ø = 16 nm) deposited on (3-mercaptopropyl)trimethoxysilane (MPTS)-modified GCE offered a basis to control the immobilization of allergen Der f2. The impedance measurements were based on the charge transfer kinetics of the [Fe(CN)6]3−/4− redox pair, compared with bare GCE, the immobilization of allergen Der f2 and the allergen–antibody interaction that occurred on the electrode surface altered the interfacial electron transfer resistance and thereby slowed down the charge transfer kinetics by reducing the active area of the electrode or by preventing the redox species in electrolyte solution from approaching the electrode. The interactions of allergen with various concentrations of monoclonal antibody were also monitored through the change of impedance response. The results showed that the electron transfer resistance increased with increasing concentrations of monoclonal antibody.
Co-reporter:Lei Qian, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2006 Volume 276(1–3) pp:235
Publication Date(Web):15 March 2006
DOI:10.1016/j.colsurfa.2005.11.047
Co-reporter:Lei Qian, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2006 Volume 278(1–3) pp:123-128
Publication Date(Web):20 April 2006
DOI:10.1016/j.colsurfa.2005.12.008
Prussian blue (PB) was modified onto surface of SiO2 nanoparticles and multiwall carbon nanotubes (MWNTs) by electrostatic assembled method. SiO2 nanoparticles and MWNTs firstly modified by polyelectrolyte exhibited positive charges and negative charged PB could be assembled onto them. UV–vs spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field-emitted scanning electron microscopy (FE-SEM) and electrochemical methods were used to characterize these composite nanomaterials. TEM and FE-SEM images showed that PB was easily assembled onto polyelectrolyte modified SiO2 nanoparticles and MWNTs. Moreover, PB on the surface of nanomaterials was stable and still kept its intrinsic electrochemical properties and high electrocatalytic activity towards hydrogen peroxide.
Co-reporter:Aixue Li, Zhaozeng Sun, Ying Ma, Fan Yang, Hongsheng Ouyang, Xiurong Yang
Talanta 2006 Volume 70(Issue 2) pp:330-335
Publication Date(Web):15 September 2006
DOI:10.1016/j.talanta.2006.02.056
Based on the multidomain structure of Pseudomonas aeruginosa exotoxin A, a fusion protein termed rPEA has been constructed, which is expected to serve as a gene carrier in vitro. The expression and purification of rPEA are described. The basal properties of rPEA as a gene carrier are evaluated by investigating its interaction with plasmid DNA and mimic biomembrane by surface plasmon resonance (SPR) and electrochemical methods. rPEA is proved to be able to bind with plasmid DNA with high affinity. It can also interact with lipid membrane and increase permeability of the membrane, so the probe molecules can easily reach the gold surface and exhibit the electrochemical response.
Co-reporter:Yufang Sha, Lei Qian, Ying Ma, Haixin Bai, Xiurong Yang
Talanta 2006 Volume 70(Issue 3) pp:556-560
Publication Date(Web):15 October 2006
DOI:10.1016/j.talanta.2006.01.007
Multilayer films containing multiwall carbon nanotubes and redox polymer were successfully fabricated on a screen-printed carbon electrode using layer-by-layer (LBL) assembled method. UV–vis spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy and electrochemical method were used to characterize the assembled multilayer films. The multilayer films modified electrodes exhibited good electrocatalytic activity towards the oxidation of ascorbic acid (AA). Compared with the bare electrode, the oxidation peak potential negatively shifted about 350 mV (versus Ag/AgCl). Furthermore, the modified screen-printed carbon electrodes (SPCEs) could be used for the determination of ascorbic acid in real samples.
Co-reporter:Lei Qian, Xiurong Yang
Talanta 2006 Volume 68(Issue 3) pp:721-727
Publication Date(Web):15 January 2006
DOI:10.1016/j.talanta.2005.05.030
A new amperometric biosensor for hydrogen peroxide was developed based on cross-linking horseradish peroxidase (HRP) by glutaraldehyde with multiwall carbon nanotubes/chitosan (MWNTs/chitosan) composite film coated on a glassy carbon electrode. MWNTs were firstly dissolved in a chitosan solution. Then the morphology of MWNTs/chitosan composite film was characterized by field-emission scanning electron microscopy. The results showed that MWNTs were well soluble in chitosan and robust films could be formed on the surface. HRP was cross-linked by glutaraldehyde with MWNTs/chitosan film to prepare a hydrogen peroxide biosensor. The enzyme electrode exhibited excellent electrocatalytic activity and rapid response for H2O2 in the absence of a mediator. The linear range of detection towards H2O2 (applied potential: −0.2 V) was from 1.67 × 10−5 to 7.40 × 10−4 M with correction coefficient of 0.998. The biosensor had good repeatability and stability for the determination of H2O2. There were no interferences from ascorbic acid, glucose, citrate acid and lactic acid.
Co-reporter:Lei Qian, Xiurong Yang
Talanta 2006 Volume 69(Issue 4) pp:957-962
Publication Date(Web):15 June 2006
DOI:10.1016/j.talanta.2005.11.053
A simple and convenient method for preparation of cobalt hexacyanoferrate (CoHCF) nanowires by electrodeposition was reported. Multiwall carbon nanotubes (MWNTs) were used as templates to fabricate CoHCF nanowires. MWNTs could affect the size of CoHCF nanoparticles and made them grow on the sidewalls of carbon nanotubes during the process of electrodeposition. Thus CoHCF nanowires could be obtained by this method. Field-emission scanning electron microscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize these nanowires. These results showed the CoHCF nanowires could be easily and successfully obtained and it gave a novel approach to prepare inorganic nanowires.
Co-reporter:Lei Qian, Yufang Sha, Xiurong Yang
Thin Solid Films 2006 Volume 515(Issue 4) pp:1349-1353
Publication Date(Web):5 December 2006
DOI:10.1016/j.tsf.2006.03.036
Au–Pt core-shell nanoparticles were prepared on glass surface by a seed growth method. Gold nanoparticles were used as seeds and ascorbic acid–H2PtCl6 solutions as growth solutions to deposit Pt shell on the surface of gold nanoparticles. These core-shell nanoparticles and their growth process were examined by UV–Vis spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and field-emission environmental scanning electron microscopy and the results indicated that the deposition speed was fast and nanoparticles with obvious core-shell structure could be obtained after 2 min. Moreover, this seed growth method for preparation of the core-shell nanoparticles is simple and convenient compared with other seed growth methods with NH4OH as a mild reductant. In addition, electrochemical experiments indicated that these Au–Pt core-shell nanoparticles had similar electrochemical properties to those of the bulk Pt electrode.
Co-reporter:Lei Qian, Xiurong Yang
Electrochemistry Communications 2005 Volume 7(Issue 5) pp:547-551
Publication Date(Web):May 2005
DOI:10.1016/j.elecom.2005.03.011
Composite films consisted of polyoxometallates and multiwall carbon nanotubes (MWNTs) were prepared by layer-by-layer assembled method. The films were characterized by environment scanning electron microscopy (ESEM) and electrochemical methods. The results showed that composite films could be successfully obtained because of electrostatic interaction between polyoxometallates and MWNTs modified by poly(diallyldimethylammonium chloride) (pMWNTs). The images of ESEM indicated that the composite film exhibited network structure. At the same time, their electrochemical activities were also studied in this paper.
Co-reporter:Lei Qian, Yang Liu, Yonghai Song, Zhuang Li, Xiurong Yang
Electrochemistry Communications 2005 Volume 7(Issue 12) pp:1209-1212
Publication Date(Web):December 2005
DOI:10.1016/j.elecom.2005.08.029
Preparation of Pt nanoclusters on the poly(amidoamine) (PAMAM) modified surface by electrodeposition was firstly reported. The presence of PAMAM could affect the growth of Pt nanostructures. Field-emitted scanning microscopy images showed that these nanoclusters were not common nanoparticles but were consisted of many small nanoparticles. The size of them could be controlled and the deposition mechanism was also discussed. This method would give a route of preparing novel nanostructures by electrodeposition.
Co-reporter:Haizhen Huang, Qiang Yuan, Xiurong Yang
Journal of Colloid and Interface Science 2005 Volume 282(Issue 1) pp:26-31
Publication Date(Web):1 February 2005
DOI:10.1016/j.jcis.2004.08.063
Gold nanoparticles were prepared in the presence of chitosan via reduction of HAuCl4 with sodium borohydride. The gold–chitosan nanocomposite was formed by adsorbing chitosan molecules onto the gold nanoparticle surfaces. The resulting gold nanoparticles were characterized by transmission electron microscopy and UV–vis spectroscopy. Morphology of gold–chitosan nanocomposite films was investigated by polarized optical microscopy. The morphology of chitosan crystal cast from the prepared nanocomposite was much different from that cast from chitosan solution due to the possible nucleation of gold nanoparticles. A branched-like structure or a cross-linked needle-like structure could be formed in nanocomposite films with different casting volumes.
Co-reporter:Haizhen Huang, Xiurong Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2005 Volume 255(1–3) pp:11-17
Publication Date(Web):21 March 2005
DOI:10.1016/j.colsurfa.2004.12.020
A one-step, size control synthesis of gold nanoparticles under mild conditions by reducing HAuCl4 with 3-thiopheneacetic acid (TA) was introduced and investigated as a function of TA concentration and molar ratio of TA to gold. Here, TA also acted as a protecting agent by loosely absorbing on the surface of produced Au0. With a relative higher concentration of TA or under a lower temperature, only spherical gold nanoparticles were formed. While lowering the concentration of TA, increasing the molar ratio of TA to gold, or increasing the reaction temperature, larger gold particles both in spherical and polygonal could be obtained. At the same time, the formation of gold nanoparticles with TA was also investigated by using in situ UV–vis absorption spectroscopy and transmission electron microscopy (TEM).
Co-reporter:Ying Ma, Cheng Yang, Nan Li, Xiurong Yang
Talanta 2005 Volume 67(Issue 5) pp:979-983
Publication Date(Web):31 October 2005
DOI:10.1016/j.talanta.2005.04.027
A sensitive method for the detection of catecholamine based on the fluorescence quenching of CdSe nanocrystals was developed. The sodium citrate-protected CdSe nanocrystals were synthesized in water solution. The fluorescence quenching of CdSe nanocrystals by dopamine, uric acid, ascorbic acid and catechol was studied; the results showed that all of these four kinds of compounds could quench the fluorescence of nanocrystals, and the quenching constant was 6.3 × 104, 2.57 × 103, 2.14 × 103 and 1.168 × 103, respectively. The order of sensitivity for the biosensor was: dopamine > lactic acid > ascorbic acid > catechol. This method shows good selectivity for dopamine, the detection limit reaches 5.8 × 10−8 M.
Co-reporter:Haizhen Huang, Qiang Yuan, Xiurong Yang
Colloids and Surfaces B: Biointerfaces 2004 Volume 39(1–2) pp:31-37
Publication Date(Web):25 November 2004
DOI:10.1016/j.colsurfb.2004.08.014
Various metal–chitosan nanocomposites were synthesized, including silver (Ag), gold (Au), platinum (Pt), and palladium (Pd) in aqueous solutions. Metal nanoparticles were formed by reduction of corresponding metal salts with NaBH4 in the presence of chitosan. And chitosan molecules adsorbing onto the surface of as-prepared metal nanoparticles formed the corresponding metal–chitosan nanocomposites. Transmission electron microscopy (TEM) images and UV–vis spectra of the nanocomposites revealed the presence of metal nanoparticles. Comparison of all the resulting particles size, it shows that silver nanoparticles are much larger than others (Au, Pt and Pd). In addition, the difference in particles size leads to develop different morphologies in the films cast from prepared metal–chitosan nanocomposites. Polarized optical microscopy (POM) images show a batonet-like structure for Ag–chitosan nanocomposites film, while for the films cast from other metal (Au, Pt, and Pd)–chitosan nanocomposites, some branched-like structures with a few differences among them were observed under POM observation.
Co-reporter:Zuojia Liu, Xiliang Zheng, Xiurong Yang, Erkang Wang, Jin Wang
Biophysical Journal (20 May 2009) Volume 96(Issue 10) pp:
Publication Date(Web):20 May 2009
DOI:10.1016/j.bpj.2008.12.3965
The affinity and specificity of drugs with human serum albumin (HSA) are crucial factors influencing the bioactivity of drugs. To gain insight into the carrier function of HSA, the binding of levamlodipine with HSA has been investigated as a model system by a combined experimental and theoretical/computational approach. The fluorescence properties of HSA and the binding parameters of levamlodipine indicate that the binding is characterized by one binding site with static quenching mechanism, which is related to the energy transfer. As indicated by the thermodynamic analysis, hydrophobic interaction is the predominant force in levamlodipine-HSA complex, which is in agreement with the computational results. And the hydrogen bonds can be confirmed by computational approach between levamlodipine and HSA. Compared to predicted binding energies and binding energy spectra at seven sites on HSA, levamlodipine binding HSA at site I has a high affinity regime and the highest specificity characterized by the largest intrinsic specificity ratio (ISR). The binding characteristics at site I guarantee that drugs can be carried and released from HSA to carry out their specific bioactivity. Our concept and quantification of specificity is general and can be applied to other drug-target binding as well as molecular recognition of peptide-protein, protein-protein, and protein-DNA interactions.
Co-reporter:
Analytical Methods (2009-Present) 2012 - vol. 4(Issue 6) pp:NaN1618-1618
Publication Date(Web):2012/04/04
DOI:10.1039/C2AY25181G
A colorimetric sulfite sensor endowed with high selectivity has been developed, using melamine as the anionic binding site and gold nanoparticles as the signaling reporter.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 9) pp:
Publication Date(Web):
DOI:10.1039/C3AY26458K
Herein, we report on the production of poly(diallydimethylammonium chloride) (PDDA) functionalized reduced graphene oxide (PDDA-rGO) with the use of PDDA as a reducing and stabilizing agent. Atomic force microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the resulting PDDA-rGO nanosheets. The PDDA-rGO nanosheets could be modified with Ag nanoparticles (AgNPs) by direct adsorption of preformed, negatively charged AgNPs. It was found that the AgNPs were distributed uniformly on the PDDA-rGO nanosheets and the obtained PDDA-rGO/AgNPs nanocomposites exhibited prominent electrocatalytic activity for the detection of hydrogen peroxide (H2O2) with a wide linear range from 100 μM to 41 mM (r = 0.997) and a rapid response upon the addition of H2O2. The detection limit was estimated to be 35 μM. Furthermore, the fabricated nonenzymatic H2O2 electrochemical sensor demonstrated excellent stability and reproducibility.
Co-reporter:Xiaowen Xu and Xiurong Yang
Analytical Methods (2009-Present) 2011 - vol. 3(Issue 5) pp:NaN1059-1059
Publication Date(Web):2011/03/24
DOI:10.1039/C1AY05042G
We have developed a facile colorimetric glucose detection method based on an organic Fenton reaction. The color of the solution gradually turned from pale yellow to purple along with the increase of glucose concentration.
Co-reporter:Jia Zhang, Chuanxia Chen, Xiaowen Xu, Xiaolei Wang and Xiurong Yang
Chemical Communications 2013 - vol. 49(Issue 26) pp:NaN2693-2693
Publication Date(Web):2013/02/15
DOI:10.1039/C3CC38298B
We have developed a Boolean NAND logic gate for the fluorescent detection of nitrite ions by using bovine serum albumin (BSA) functionalized gold nanoclusters.
Co-reporter:Xiaowen Xu and Xiurong Yang
Chemical Communications 2014 - vol. 50(Issue 7) pp:NaN807-807
Publication Date(Web):2013/11/14
DOI:10.1039/C3CC47102K
Herein we report the reversion of DNA strand displacement using functional nucleic acids as toeholds.
Co-reporter:Jian Feng, Hui Zhu, Xiaolei Wang and Xiurong Yang
Chemical Communications 2012 - vol. 48(Issue 44) pp:NaN5454-5454
Publication Date(Web):2012/04/26
DOI:10.1039/C2CC31702H
This communication describes a new type of alloyed Cd–In–S quantum dots (CdIS QDs) with ultra small particle size and broadly tunable fluorescence emission from 450 to 700 nm. The band gap of CdIS QDs was mainly controlled by their composition rather than their particle size. The CdIS–ZnS core–shell nanocrystals exhibited significantly improved optical properties and chemical stabilities, with the PL quantum yield (QY) of up to 60%.
Co-reporter:Xiaowen Xu, Jia Zhang, Fan Yang and Xiurong Yang
Chemical Communications 2011 - vol. 47(Issue 33) pp:NaN9437-9437
Publication Date(Web):2011/07/21
DOI:10.1039/C1CC13459K
Herein we report the “OR” and “AND” colorimetric logic gates for small molecules using split/integrated aptamers and unmodified gold nanoparticles, which generate visually observed outputs according to Boolean operations.
Co-reporter:Yong Wang, Yu Zheng, Fan Yang and Xiurong Yang
Chemical Communications 2012 - vol. 48(Issue 23) pp:NaN2875-2875
Publication Date(Web):2012/02/06
DOI:10.1039/C2CC16279B
A real-time, label-free dual polarisation interferometry technique was used to investigate the interaction of Hg2+ with a 21-mer T-rich oligonucleotide and further construct a Hg2+ biosensor based on thymine–Hg2+–thymine coordination chemistry.
Co-reporter:Hui Zhu, Xiaolei Wang, Yali Li, Zhongjun Wang, Fan Yang and Xiurong Yang
Chemical Communications 2009(Issue 34) pp:NaN5120-5120
Publication Date(Web):2009/07/16
DOI:10.1039/B907612C
We present a facile, economical microwave pyrolysis approach to synthesize fluorescent carbon nanoparticles with electrochemiluminescence properties.
Co-reporter:Jian Feng, Ming Sun, Fan Yang and Xiurong Yang
Chemical Communications 2011 - vol. 47(Issue 22) pp:NaN6424-6424
Publication Date(Web):2011/05/09
DOI:10.1039/C1CC11754H
A facile approach to synthesize ZnxCuyInS1.5+x+0.5y nanocrystal emitters was presented. The compositions of these nanocrystals were precisely controlled, and the relative PL quantum yields were up to 40%, with tunable emissions in 450–640 nm.
Co-reporter:Xiaolei Wang, Fan Yang, Wen Yang and Xiurong Yang
Chemical Communications 2007(Issue 42) pp:NaN4421-4421
Publication Date(Web):2007/08/17
DOI:10.1039/B708662H
In this study, ZnO nanowire arrays with different orientations were prepared. Confocal laser scanning microscopy (CLSM) and field-emission scanning electron microscope (FE-SEM) technique were employed for understanding the disparities in antibacterial activity between different orientations of ZnO nanoarrays. The effects of the different planes of ZnO nanowire were also discussed for the first time.
Co-reporter:Xiaolei Wang, Hui Zhu, Xuexia Liu and Xiurong Yang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 11) pp:NaN1578-1578
Publication Date(Web):2013/01/10
DOI:10.1039/C3TB00005B
Artificial magnetotactic probiotics (AMPs) are developed to combine living probiotic benefits with magnetic targeting properties. Experimental investigations are carried out to study their surface nano-modification process, viability and magnetic motility behavior. Subsequent in vivo studies indicate that AMPs can be applied to inhibit different invasive pathogens, including some antibiotic-resistant strains. Compared with conventional antibiotic therapy, AMPs represent an efficient and accurate alternative treatment for dealing with microbial threats, and have the potential to minimize a wide range of adverse effects.
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