Detection of Listeria Monocytogenes by Electrochemical Impedance Spectroscopy

Listeria monocytogenes is detected by electrochemical impedance spectroscopy using a mouse monoclonal antibody immobilized onto an Au electrode. This yields sensitivities of 0.825k cm(2)/(CFU/mL) and 1.129k cm(2)/(CFU/mL) and detection limits of 5CFU/mL and 4CFU/mL for ideal solutions and filtered tomato extract, respectively. Control experiments with an Au electrode onto which a mouse monoclonal antibody to GAPDH is immobilized demonstrate that non-specific adsorption is insignificant for the system and methodology studied here. Control experiments with Salmonella enterica demonstrate no cross-reactivity to this food pathogen. Potential technological hurdles to development of a multiplexed impedance biosensor for food pathogens are also discussed.