Impedance biosensor based on interdigitated electrode arrays for detection of low levels of E.coli O157:H7

We report an interdigitated electrode array (IDEA) impedance biosensor with rapid detection of Escherichia coli O157:H7. This biosensor has significantly better detection capability compared with the conventional microbiological testing method. The total detection time for this biosensor is under 3 hours. Dielectrophoresis (DEP) is used in conjunction with impedance spectroscopy to improve the detection capability of the biosensor. The IDEA surface is functionalized using anti-E.coli antibody for selectivity of the bacteria. The dose response was in-between 3 × 10⁶ CFU/mL and 3 × 10² CFU/mL. This is 10 fold better than the detection limit previously reported using impedance based biosensors.