Disposable amperometric immunosensing strips fabricated by Au nanoparticles-modified screen-printed carbon electrodes for the detection of foodborne pathogen Escherichia coli O157:H7.
A disposable amperometric immunosensing strip was fabricated for rapid detection of Escherichia coli O157:H7. The method uses an indirect sandwich enzyme-linked immunoassay with double antibodies. Screen-printed carbon electrodes (SPCEs) were framed by commercial silver and carbon inks. For electrochemical characterization the carbon electrodes were coupled with the first E. coli O157:H7-specific antibody, E. coli O157:H7 intact cells and the second E. coli O157:H7-specific antibody conjugated with horseradish peroxidase (HRP). Hydrogen peroxide and ferrocenedicarboxylic acid (FeDC) were used as the substrate for HRP and mediator, respectively, at a potential +300 mV vs. counter/reference electrode. The response current (RC) of the immunosensing strips could be amplified significantly by 13-nm diameter Au nanoparticles (AuNPs) attached to the working electrode. The results show that the combined effects of AuNPs and FeDC enhanced RC by 13.1-fold. The SPCE immunosensing strips were used to detect E. coli O157:H7 specifically. Concentrations of E. coli O157:H7 from 10(2) to 10(7)CFU/ml could be detected. The detection limit was approximately 6CFU/strip in PBS buffer and 50CFU/strip in milk. The SPCE modified with AuNPs and FeDC has the potential for further applications and provides the basis for incorporating the method into an integrated system for rapid pathogen detection.
Lin
Yueh-Hui
YH
Department of Biological Science and Technology, National Chiao Tung University, Hsinchu 30068, Taiwan.
Chen
Sz-Hau
SH
Chuang
Yao-Chen
YC
Lu
Yi-Chen
YC
Shen
Thomas Y
TY
Chang
C Allen
CA
Lin
Chih-Sheng
CS
D015374:Biosensing Techniques / Q000295:instrumentation; D002244:Carbon / Q000737:chemistry; D015169:Colony Count, Microbial / Q000295:instrumentation; D004209:Disposable Equipment; D004563:Electrochemistry / Q000295:instrumentation*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006046:Gold / Q000737:chemistry; D008839:Microelectrodes; D053758:Nanoparticles / Q000737:chemistry; D011934:Reagent Strips; D013499:Surface Properties
D011934:Reagent Strips; D002244:Carbon; D006046:Gold