Development of a Disposable Impedance Biosensor and its Application for Determination of Escherichia coli O157:H7

Abstract

<abstract> <bold><sc>Abstract.</sc></bold> The development of cost-effective, robust, and rugged biosensing devices is of great interest for point-of-care testing and on-site monitoring. Here we report a facile approach to building high-performance disposable impedance biosensors for sensitive and selective determination of Escherichia coli O157:H7. Gold nanoparticles and graphene modified screen-printed carbon as the electrode substrate were employed in this impedance biosensor. The immobilization of anti-E. coli O157:H7 antibodies on the electrode surface was performed by simple physical adsorption. Electrochemical impedance spectroscopy was used to detect E. coli O157:H7 captured on the disposable biosensor. Results showed that the developed immunosensor possesses excellent sensing performance, such as wide linear range (1.5 × 10³ to 1.5 × 10⁷ cfu mL^-1), low detection limit (1.5 × 10³ cfu mL^-1), and excellent specificity (no significant interference from E. coli DH 5α, Staphylococcus aureus, or Listeria monocytogenes). The strategy of structurally integrating metal nanomaterials, graphene, and screen-printed electrodes provides new insight into the design of disposable and high-performance immunosensors for routine sensing applications.