Issue 12, 2013

Solid-state voltammetry-based electrochemical immunosensor for Escherichia coli using graphene oxide–Ag nanoparticle composites as labels

Abstract

A new electrochemical immunosensor based on solid-state voltammetry was fabricated for the detection of Escherichia coli (E. coli) by using graphene oxide–Ag nanoparticle composites (P-GO–Ag) as labels. To construct the platform, Au nanoparticles (AuNPs) were first self-assembled on an Au electrode surface through cysteamine and served as an effective matrix for antibody (Ab) attachment. Under a sandwich-type immunoassay format, the analyte and the probe (P-GO–Ag–Ab) were successively captured onto the immunosensor. Finally, the bonded AgNPs were detected through a solid-state redox process in 0.2 M of KCl solution. Combining the advantages of the high-loading capability of graphene oxide with promoted electron-transfer rate of AuNPs, this immunosensor produced a 26.92-fold signal enhancement compared with the unamplified protocol. Under the optimal conditions, the immunosensor exhibited a wide linear dependence on the logarithm of the concentration of E. coli ranging from 50 to 1.0 × 106 cfu mL−1 with a detection limit of 10 cfu mL−1. Moreover, as a practical application, the proposed immunosensor was used to monitor E. coli in lake water with satisfactory results.

Graphical abstract: Solid-state voltammetry-based electrochemical immunosensor for Escherichia coli using graphene oxide–Ag nanoparticle composites as labels

Supplementary files

Article information

Article type
Paper
Submitted
08 Jan 2013
Accepted
11 Apr 2013
First published
11 Apr 2013

Analyst, 2013,138, 3388-3393

Solid-state voltammetry-based electrochemical immunosensor for Escherichia coli using graphene oxide–Ag nanoparticle composites as labels

X. Jiang, K. Chen, J. Wang, K. Shao, T. Fu, F. Shao, D. Lu, J. Liang, M. F. Foda and H. Han, Analyst, 2013, 138, 3388 DOI: 10.1039/C3AN00056G

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