A Bipolar Electrode-Electrochemiluminescence Sensor for Salmonella Typhimurium Detection Based on Bacterial Surface Imprinted Polymer

Abstract

A simple and effective method was used to prepare cathode of bipolar electrode (BPE) for polydopamine (PDA) bacterial surface imprinted polymer (SIP). On this basis, bipolar electrode-electrochemiluminescence (BPE-ECL) sensor for Salmonella typhimurium (S. typhimurium) detection was constructed. On the one hand, dopamine (DA) was used as a monomer and S. typhimurium as a template molecule. By electropolymerization, a polymer film template encapsulating the target bacteria is formed at the cathode of the BPE. The template is subsequently removed, at which point a molecular surface imprinted film forms on the cathode surface. In this way, PDA SIP capture probe capable of recognizing and binding to target bacteria were successfully prepared. On the other hand, Fc-aptamer-S. typhimurium as a signal probe specifically recognized S. typhimurium. At this point, a sandwich structure is formed in which the dual probes recognize the target bacteria. After applying a certain driving voltage, the oxidation product Fc+ accelerated the luminescence of the [Ru(bpy)3]2+/TPrA system on the anode, and the intensity of the ECL increased. By the BPE-ECL sensor, 101 to 106 CFU mL-1 S. typhimurium can be sensitively detected with a detection limit of 1 CFU mL-1. The BPE-ECL sensor had high selectivity for target analytes, and sufficient stability and sensitivity for the detection of foodborne pathogens.

Keywords: DA, SIP, BPE-ECL, S. typhimurium