Electrochemical\nDetection of Pseudomonas\naeruginosa Quorum Sensing Molecule (<i>S</i>)‑<i>N</i>‑Butyryl Homoserine Lactone Using\nMolecularly Imprinted Polymers

Pseudomonas aeruginosa is a multidrug-resistant\nGram-negative bacterium that poses a significant threat to public\nhealth, necessitating rapid and on-site detection methods for rapid\nrecognition. The goal of the project is therefore to indirectly detect\nthe presence of P. aeruginosa in environmental\nwater samples targeting one of its quorum-sensing molecules, namely,\n(<i>S</i>)-<i>N</i>-butyryl homoserine lactone\n(BHL). To this aim, molecularly imprinted polymers (MIPs) were synthesized\nvia bulk free-radical polymerization using BHL as a template molecule.\nThe obtained MIP particles were immobilized onto screen-printed electrodes\n(MIP-SPEs), and the BHL rebinding was analyzed via electrochemical\nimpedance spectroscopy (EIS). To study the specificity of the synthesized\nMIPs, isotherm curves were built after on-point rebinding analysis\nperformed via LC–MS measurements for both MIPs and NIPs (nonimprinted\npolymers, used as a negative control), obtaining an imprinting factor\n(IF) of 2.8 (at <i>C</i><sub>f</sub> = 0.4 mM). The MIP-SPEs\nwere integrated into an electrochemical biosensor with a linear range\nof 1 × 10<sup>1</sup>–1 × 10<sup>3</sup> nM and a\nlimit of detection (LoD) of 31.78 ± 4.08 nM. Selectivity measurements\nwere also performed after choosing specific interferent molecules,\nsuch as structural analogs and potential interferents, followed by\non-point analysis performed in spiked tap water to prove the sensor’s\npotential to detect the presence of the quorum-sensing molecule in\nenvironmentally related real-life samples.