Hybrid nanoflower-based electrochemical lateral flow immunoassay for Escherichia coli O157 detection

An electrochemical biosensor has been developed for detection of Escherichia coli O157 by integrating lateral flow with screen-printed electrodes. The screen-printed electrodes were attached under the lateral flow detection line, and organic–inorganic nanoflowers prepared from E. coli O157-specific antibodies as an organic component were attached to the lateral flow detection line. In the presence of E. coli O157, an organic–inorganic nanoflower-E. coli O157-antimicrobial peptide-labelled ferrocene sandwich structure is formed on the lateral flow detection line. Differential pulse voltammetry is applied using a smartphone-based device to monitor ferrocene on the detection line. The resulting electrochemical biosensor could specifically detect E. coli O157 with a limit of detection of 25 colony-forming units mL⁻¹. Through substitution of antibodies of organic components in organic–inorganic nanoflowers, biosensors have great potential for the detection of other pathogens in biomedical research and clinical diagnosis.