MOF-encapsulated quantum dots/magnetic graphene composite fluorescence-encoded entropy-driven aptasensing platform...

Rapid and accurate identification of pathogenic Vibrio in complex aquatic product matrices is critical for food safety. Herein, an entropy-driven detection platform (SEFAM) based on triple fluorescence-coded quantum dots (QDs) probes encapsulated in metal-organic framework (MOF) and mesophilic Clostridium butyricum Argonaute (CbAgo) is developed, which enables multiplexed and DNA extraction-free detection of Vibrio in aquatic products. The SEFAM platform utilizes programmable magnetic aptamer switches to achieve targeted bacterial recognition, thereby initiating the entropy-driven circuit (EDC) response and releasing large quantities of guide DNA (gDNA) to stimulate the specific cleavage activity of CbAgo. The multicolor quantum dots@MOF-5 with different emission bands (430 nm, 525 nm, and 635 nm) were modified with single-stranded DNA (ssDNA) and conjugated with magnetic graphene oxide (mGO), serving as triple fluorescent probes to distinguish three Vibrio species. The platform achieved the limits of detection (LOD) for Vibrio parahaemolyticus, Vibrio vulnificus, and Vibrio cholerae as 6.8, 4.3 and 6.2 CFU/mL respectively, and the linear range is 10¹-10⁸ CFU/mL. Furthermore, the practical applicability of the SEFAM platform was successfully demonstrated through validation using 44 real samples. This study has presented a highly specific, stable and repeatable biosensor, providing a promising method for the on-site multiplex detection of pathogenic Vibrio in complex matrices.