Signal-off impedimetric immunosensor for the detection of Escherichia coli O157:H7.

A signal-off impedimetric immune-biosensor based on gold nanoparticle (AuNP)-mediated electron transfer (ET) across a self-assembled monolayer (SAM) was the developed for highly sensitive detection of Escherichia coli O157:H7 bacteria. The biosensor was fabricated by covalently grafting an anti-Escherichia coli O157:H7 antibody onto SAM-modified gold electrodes. Following bacterial capture, the sensor was further modified by the gold nanoparticles (AuNPs).