Sensitive and selective electrochemical sensing of Escherichia coli O157:H7 based on bacteria-imprinted polymer and Concanavalin A-functionalized Fe3O4 nanozyme

Rapid and reliable detection of foodborne pathogens is essential for ensuring food safety, yet achieving high selectivity and sensitivity in complex matrices remains challenging. Herein, we report a sensitive and selective electrochemical sensing platform integrating a bacteria-imprinted polymer (BIP) capture interface with concanavalin A-functionalized Fe 3 O 4 (Fe 3 O 4 -ConA) for the detection of Escherichia coli O157:H7 ( E. coli O157:H7). The BIP film was electropolymerized in situ on glassy carbon electrode to generate recognition sites for efficient capture of E. coli O157:H7. Subsequently, Fe 3 O 4 -ConA bound to surface glycans on the captured bacteria through lectin-glycan interactions, forming a sandwich-like sensing interface. The anchored Fe 3 O 4 nanozyme catalyzed the H 2 O 2 -mediated oxidation of o -phenylenediamine, producing amplified electrochemical signals for bacterial quantification. Benefiting from the combination of imprinting-based recognition and catalytic amplification, the sensor achieved an ultrasensitive detection limit of 2.8 CFU mL −1 and a linear range from 10 1 to 10 5 CFU mL −1 . Recoveries of 93.29–113.62% were obtained in spiked milk, fish, and juice samples, with reliable detection down to 10 CFU mL −1 in complex food matrices. This work provides an effective strategy for constructing nanozyme-amplified electrochemical sensors for sensitive and selective monitoring of foodborne pathogens.