Time filter

Source Type

Xu Q.,Yangzhou University | Xu Q.,Jiangsu Key Laboratory of Environmental Engineering and Monitoring | Lu G.-J.,Yangzhou University | Bian X.-J.,Yangzhou University | And 6 more authors.
Materials Science and Engineering C

This work reports a new method for the preparation and application of a kind of biocompatible calcium phosphate-gold nanoparticles (Ca 3(PO 4) 2-AuNPs) nanocomposite. UV-vis spectroscopy and transmittance electron microscopy (TEM) have been used to monitor the formation process of the nanocomposite and to examine the interaction between calcium phosphate and gold nanoparticles (AuNPs). The nanocomposite has multiple sites and improved conductivity which make it suitable for the binding of proteins to construct electrochemical sensors. Myoglobin (Mb) adsorbed on the nanocomposite retained its native structure which was proved by Fourier transform infrared spectroscopy (FTIR). Direct electron transfer between the adsorbedMb and the electrode was observed. Further results demonstrated that the adsorbed Mb has good electrocatalytic activity towards the reduction of H 2O 2 in the absence of any mediator. © 2011 Elsevier B.V. All rights reserved. Source

Xu Q.,Yangzhou University | Xu Q.,Jiangsu Key Laboratory of Environmental Engineering and Monitoring | Li X.,Yangzhou University | Zhou Y.-E.,Yangzhou University | And 5 more authors.
Analytical Methods

A novel biosensor containing horseradish peroxidase (HRP) and graphene for the detection of 2,4-dichlorophenol (2,4-DCP) is described. The radicals, formed during the enzymatic oxidation of 2,4-DCP in the presence of H 2O 2, were reduced electrochemically on the electrode. The reduction current was proportional to the concentration of 2,4-DCP in the solution. The effects of HRP concentration, pH, applied potential and H 2O 2 concentration on the analytical performances of the biosensor are investigated. Under the optimal conditions, the proposed biosensor exhibited a wide linearity for 2,4-DCP detection from 1.0 × 10 -8 M to 1.3 × 10 -5 M, and the detection limit was down to 5.0 × 10 -9 M (S/N = 3). In comparison with the reported 2,4-DCP sensors, this proposed biosensor exhibits wide linearity and low detection limit. Moreover, it also has good reproducibility and long-term stability. © The Royal Society of Chemistry. 2012. Source

Xu D.,Yangzhou University | Liu L.,Yangzhou University | Guan J.,Peoples Hospital of Jiangsu Province | Xu J.,Yangzhou University | And 6 more authors.
Microchimica Acta

We report on label-free immunosensors for the highly sensitive detection of avian influenza virus. The method makes use of the microcantilevers of an atomic force microscope onto which monoclonal antibodies against avian influenza virus were covalently immobilized. The factors influencing the performance of the resulting immunosensors were optimized by measuring the deflections of the cantilever via optical reflection, and this resulted in low detection limits and a wide analytical range. The differential deflection signals revealed specific antigen binding and their intensity is proportional to the logarithm of the concentrations of the virus in solution. Under optimal conditions, the immunosensors exhibit a linear response in the 7.6 ng mL-1 to 76 μg mL-1 concentration range of avian influenza virus, and the detection limit is 1.9 ng mL-1. [Figure not available: see fulltext.] © 2013 Springer-Verlag Wien. Source

Xu Q.,Yangzhou University | Xu Q.,Jiangsu Key Laboratory of Environmental Engineering and Monitoring | Leng J.,Yangzhou University | Li H.-B.,Yangzhou University | And 4 more authors.
Reactive and Functional Polymers

Polyaniline/gold nanoparticles (PANI/AuNPs) nanocomposites were prepared using a simple self-assembly procedure. Polyvinyl pyrrolidone (PVP) was used as a stabilizing ligand of AuNPs and was shown to prevent the aggregation of AuNPs and to improve the affinity of AuNPs to PANI. By varying the ratio of PANI to AuNPs, the amount of loaded AuNPs was effectively controlled. UV-vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and electrochemical methods were used to characterize the nanocomposites. The nanocomposites showed electroactivity in neutral solution, making them promising candidates for various bioanalytical applications. A sensor constructed using PANI/AuNPs nanocomposites showed 6-fold higher electrocatalytic activity toward the oxidation of ascorbic acid than that composed of a pure PANI-modified electrode. © 2010 Elsevier Ltd. All rights reserved. Source

Xu Q.,Yangzhou University | Xu Q.,Jiangsu Key Laboratory of Environmental Engineering and Monitoring | Du S.,Yangzhou University | Jin G.,Yangzhou University | And 3 more authors.
Microchimica Acta

A method was developed for the detection of the insecticide acetamiprid based on the strong interaction of the cyano group of acetamiprid with gold nanoparticles (AuNPs). The interaction results in the aggregation of gold nanoparticles and is accompanied by a color change from red to purple. The concentration of acetamiprid can be determined qualitatively and quantitatively by visually monitoring the color change or by using a spectrometer. Transmittance electron microscopy and UV-vis spectroscopy have been used to characterize the process. The experimental parameters were optimized with regard to the size of the AuNPs, pH, and incubation time. Under optimal experimental conditions, linear relationships between the logarithm of the concentration of acetamiprid and the absorbance were found over the range of 0.66 to 6.6 μM for AuNPs with diameters of 22.0 ± 1.0 nm and of 6.6-66 μM for AuNPs with diameters of 15.0 ± 1.0 nm. This method was successfully applied to detect acetamiprid in vegetables. © 2011 Springer-Verlag. Source

Discover hidden collaborations