Highly selective detection of Escherichia coli O157:H7 based on micro-gapped interdigitated electrode arrays

Abstract

Development of effective pathogen detection systems is critical for human health. In this study, a micro-gapped interdigitated electrode array-based immunosensor chip is constructed for the detection of a typical pathogen, Escherichia coli (E. coli) O157:H7. The immunosesnor chip was prepared via photolithography and characterized by a digital camera, optical microscope and scanning electron microscope. The E. coli O157:H7 detection mechanism is based on an enzyme-linked, sandwiched immunoassay with enzymatic silver deposition. Our results revealed that the proposed immunosensor chip showed selective electrical response towards E. coli O157:H7 over other bacteria including Hemolytic streptococcus, Staphylococcus aureus, Salmonella, Pseudomonas aeruginosa, Chronobacter sakazakii and Bacillus cereus. Our assay exhibited potential practical applications for E. coli O157:H7 determination in water and our methodology might be applied to detect different pathogens by simply selecting specific antibodies.

Keywords

• Escherichia coli O157:H7
• micro-gapped interdigitated electrode array
• immunoassay
• electrochemical sensing