Molecularly imprinted multifunctional polymer-modified single-atom-homojunctions for sensitive photoelectrochemical Escherichia coli O157:H7 sensing.

BACKGROUND

Foodborne illnesses induced by foodborne pathogenic bacteria pose a tremendous risk to human health and result in massive economic losses. Therefore, the development of rapid detection methods for foodborne pathogenic bacteria is one of the major measures to safeguard food safety. Molecularly imprinted polymers (MIPs)-based photoelectrochemical (PEC) sensors have emerged as an attractive method for the determination of pathogenic bacteria in environmental surveillance. However, the MIPs films in developed PEC sensors are typically non-photoreactive polymers with single functional monomer, causing low recognition performance.

RESULTS

Here, we designed a novel PEC sensor based on MIPs-modified single-atom-homojunctions (PHI-Cd) for sensitive quantitative detection of Escherichia coli O157:H7 (E. coli O157:H7). Studies have revealed that MIPs prepared with two functional monomers, 1,4-Di (2-thienyl)-1,4-butanedione and piracetam, possess the dual functions of specific recognition and sensitization. The built-in electric field formed inside the PHI-Cd heterojunction can effectively promote the electron-hole pair separation process. Moreover, PHI-Cd exhibited excellent peroxidase-like activity, which effectively catalyzed the production of O from HO. After the addition of HO to the reaction solution, the production of O provided a large number of electron acceptors for the reaction, serving as a signal amplifier. The prepared MIPs-PEC sensor can quantitatively monitor E. coli O157:H7 from 10.0 to 10 CFU/mL, with a LOD of 3.0 CFU/mL. Notably, the non-covalent interaction mode and binding energy between the functional monomer and the E. coli O157:H7 phospholipid bilayer was acknowledged by molecular docking studies.

SIGNIFICANCE

On this basis, this research opens up a wider range of possibilities to analyze the binding sites of template and functional monomers as well as the mechanism of their interactions in the MIPs-PEC sensor, which provided new insights for efficient monitoring of foodborne pathogens to safeguard environmental health and food safety.