Self-Cleaning Electrochemical Biosensor Based on MCOF@Ag for Simultaneous Pathogen Detection and Photocatalytic Inactivation

Abstract

Efficient detection and real-time inactivation of pathogens are critical for the prevention and control of infectious diseases. Herein, based on a Ag nanoparticle-decorated metal-covalent organic framework (MCOF@Ag), a self-cleaning electrochemical biosensor was developed for ultrasensitive bacteria detection and inactivation. The as-synthesized MCOF@Ag (designated as GZHMU-2@Ag) exhibited a unique nanoflowerlike structure, which facilitated efficient electron transfer and significantly enhanced both electrochemical and photocatalytic activities. Staphylococcus aureus was chosen as a pathogen model. By immobilizing S. aureus-specific SA31 aptamers on the GZHMU-2@Ag-based electrode, measurable electrochemical changes were induced by the binding of target bacteria. Therefore, the biosensor enabled the logarithmic quantification of S. aureus across a broad range (1 to 105 CFU/mL), demonstrating a limit of detection of 1 CFU/mL. More importantly, owing to excellent photocatalytic activity, the GZHMU-2@Ag-based electrode achieved 99.4% inactivation of captured bacteria within 20 min of visible light exposure through photocatalytic generation of reactive oxygen species. Subsequent regenerative desorption allowed the electrode to be self-cleaned and reused, demonstrating a satisfactory detection performance. This study provides a strategy for the simultaneous detection and inactivation of pathogens with one MCOF@Ag electrode, highlighting the potential of MCOF-based materials in advanced electrochemical biosensing and antibacterial applications.