Development of a disposable impedance biosensor and its application for determination of <i>Escherichia coli</i> O157:H7

Abstract

Abstract. The development of cost-effective, robust, and rugged biosensing devices is of great interest for point-of-care testing and on-spot monitoring. Here we reported a facile approach to build high-performance disposable impedance biosensor for sensitive and selective determination of Escherichia coli O157:H7. Gold nanoparticles and graphene modified screen-printed carbon electrode was employed as the electrode substrate in this impedance biosensor. The immobilization of anti-Escherichia coli O157:H7 antibodies on electrode surface were performed by simple physical adsorption. Electrochemical impedance spectroscopy was used to detect Escherichia coli O157:H7 captured on the disposable biosensor. Results show that the developed immunosensor possesses greatly enhanced sensing performance, such as wide linear range (1.5 A— 10 3 - 1.5 A— 10 7 cfu mL −1 ), low detection limit (1.5 A— 10 3 cfu mL −1 ), and excellent specificity. The strategy of structurally integrating metal nanomaterials, graphene, and screen-printed electrode would provide new insight into design of disposable and high-performance immunosensors for routine sensing applications.