A four-in-one aptamer-functionalized CDs@MIL-53(Fe) nanozyme platform for closed-loop detection, sterilization and safe disposal of foodborne pathogens

Carbon dots endowed MIL-53(Fe) with four synergistic functions. • A dual-mode aptasensor enabled accurate pathogen detection. • A closed-loop strategy integrated detection with safe pathogen elimination. • A paper-based assay achieved rapid visual food safety screening. The increasing prevalence of foodborne pathogens has created an urgent need for integrated strategies on combining rapid on-site detection with safe inactivation. In this study, a multifunctional aptamer-modified CDs@MIL-53(Fe) nanocomposite was developed to construct a closed-loop management platform integrating target recognition, dual-mode signal transduction, and in situ photothermal-chemodynamic sterilization. This nanocomposite uniquely combined four functionalities within a single material: fluorescence emission, oxidase/peroxidase-mimicking activity, photocatalytic reactive oxygen species generation, and efficient photothermal conversion. After aptamer functionalization, the platform enabled both colorimetric and fluorescence dual-mode detection. Using Listeria monocytogenes as a proof-of-concept model, detection limits of 6.01 CFU/mL (colorimetric) and 61.38 CFU/mL (fluorescence) were obtained with the proposed method, within a linear range of 10 1 –10 6  CFU/mL. Importantly, the sensing mechanism allowed easy adaptation to other pathogens by simply replacing the aptamer. After detection, the same platform achieved in situ synergistic sterilization (>99.5%), and the used test strips could be safely discarded. Validation in chicken breast and milk samples, along with successful translation to a paper-based device, demonstrated the practical application potential of this universal pathogen management strategy in food safety supervision and disease prevention.