Disposable amperometric immunosensing strips fabricated by Au nanoparticles-modified screen-printed carbon electrodes for the detection of foodborne pathogen Escherichia coli O157:H7

Yueh Hui Lin, Sz Hau Chen, Yao Chen Chuang, Yi Chen Lu, Thomas Y. Shen, C. Allen Chang*, Chih-Sheng Lin

*Corresponding author for this work

Research output: Contribution to journalArticle

127 Scopus citations

Abstract

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 102 to 107 CFU/ml could be detected. The detection limit was approximately 6 CFU/strip in PBS buffer and 50 CFU/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.

Original languageEnglish
Pages (from-to)1832-1837
Number of pages6
JournalBiosensors and Bioelectronics
Volume23
Issue number12
DOIs
StatePublished - 15 Jul 2008

Keywords

  • Electrochemistry
  • Escherichia coli O157:H7
  • Immunosensor
  • Nanoparticles
  • Screen-printed carbon electrode

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