Ultrasensitive detection of E. coli O157:H7 with biofunctional magnetic bead concentration via nanoporous membrane based electrochemical immunosensor

► Magnetic bead conjugated bacteria cells were concentrated by external magnetic field. ► Concentrated bacteria cells were captured by antibody immobilized nanoporous membrane immunosensor. ► A linear relationship between bacteria concentration and impedance signal was found in the range from 100 to 104 CFU/mL. ► The detection limit of 10 CFU/mL was achieved for E coli O157:H7 detection.