title: 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 × 10(6) 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.
authors: State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors: Xiaochun
authors: X
authors: Jiang
authors: Kun
authors: K
authors: Chen
authors: Jing
authors: J
authors: Wang
authors: Kang
authors: K
authors: Shao
authors: Tao
authors: T
authors: Fu
authors: Feng
authors: F
authors: Shao
authors: Donglian
authors: D
authors: Lu
authors: Jiangong
authors: J
authors: Liang
authors: M Frahat
authors: MF
authors: Foda
authors: Heyou
authors: H
authors: Han
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000379:methods*; D002021:Buffers; D004563:Electrochemistry; D004566:Electrodes; D004926:Escherichia coli / Q000302:isolation & purification*; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D007118:Immunoassay / Q000379:methods*; D060106:Lakes / Q000382:microbiology; D053768:Metal Nanoparticles / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D015203:Reproducibility of Results; D012834:Silver / Q000737:chemistry*; D013194:Staining and Labeling
chemical_list: D055910:Antibodies, Immobilized; D002021:Buffers; D010087:Oxides; D012834:Silver; D006046:Gold; D006108:Graphite