Selective detection of Escherichia coli based on BSA/CNTs/ UIO-66-NH₂ molecularly imprinted electrochemical sensors

As a common contaminating bacterium, Escherichia coli (E. coli) has caused severe harm in various fields such as food, healthcare, and the environment. Traditional detection methods for Escherichia coli, owing to factors like high cost and low efficiency, are unable to meet the detection requirements at the present stage. Therefore, the development of a simple, rapid, and highly efficient detection method for Escherichia coli represents an urgent issue that needs to be addressed promptly. This study focused on the development of a highly selective molecularly imprinted electrochemical sensor for E. coli. Molecularly imprinted polymers (MIPs) were prepared by electropolymerization on the surface of glassy carbon electrode using o-phenylenediamine as the functional monomer, aminated metal-organic frameworks (MOFs) and carbon nanotubes (CNTs) as the composites, and bovine serum albumin (BSA) was added into the polymer film to attenuate the non-imprinting effect. The linear range of the sensor was 10-10⁷ CFU/mL and the detection limit was 5.2 CFU/mL. Good recovery rates were shown in real samples of drinking water, milk and orange juice. In addition, the good binding ability of the E. coli template molecule to the functional monomer o-phenylenediamine was verified by molecular docking and molecular dynamics (MD) simulations. This study was able to detect E. coli in 20 min, which provides a more open idea for the application of rapid detection of E. coli on-site, as well as the construction of molecularly imprinted electrochemical sensors and the analysis of the binding mechanism between template molecules and functional monomers.