Post-functionalization of TEMPO onto ROMP polymers for high-sensitivity electrochemical detection of Staphylococcus aureus: A surface-initiated biosensing strategy

Ultrasensitive quantitative detection of Staphylococcus aureus ( S. aureus ) is critically important for preventing food-borne illnesses caused by this pathogen. In this study, an electrochemical biosensor for accurate detection of S. aureus was developed for the first time by in situ ring-opening metathesis polymerization (ROMP) of bacterial surface proteins. In brief, the glassy carbon electrode (GCE) was functionalized via electrochemical reduction of aryl diazonium salts to provide binding sites for specific capture probe-aptamer. 2,2,6,6-tetramethylpiperidin-4-ylamine (TEMPO) was modified on the ROMP polymer by post-functionalization method to achieve signal amplification. In the concentration range of 1.0 × 10 1  CFU/mL ∼ 1.0 × 10 8  CFU/mL, the detection limit of the electrochemical biosensor for S. aureus was 2.2 CFU/mL. In addition, the sensor has excellent reproducibility and recognition ability, and can accurately detect S. aureus in the presence of a variety of bacteria. To validate practical utility, the biosensor was successfully applied to detect S. aureus in real food samples—including milk and orange juice—yielding high recovery rates and reliable quantification. The sensor adopts a mild and environmentally friendly ROMP signal amplification strategy and has excellent analytical performance, which has important potential in the field of accurate identification of food-borne pathogens.