Impedance biosensor for rapid detection of low concentration of E.coli 0157:H7

An Impedance biosensor for rapid detection of low concentration of E.coli O157:H7 was designed, fabricated and tested. The device consists of specially designed focusing and sensing regions embedded in SU8 microchannel. The focusing region, consists of ramped-down vertical and thin-film focusing electrode pair, exerts positive dielectrophoretic forces to concentrate the bacteria towards the center of microchannel while the bulk fluid exits from the outer two channels. The concentrated bacteria will continue to flow toward the sensing region which consists of anti-E.coli antibody coated interdigitated electrode arrays. The biosensor was able to detect concentrations as low as 39 CFU/mL within 2 hours.