Plataforma de biosensores duales habilitada por nanoenzima PS-NH2-BDC@Fe2O3 auto-fluorescente para la cuantificación...

Developing efficient and reliable sensing strategies for the detection of ochratoxin A (OTA) in complex food matrices is crucial to prevent mycotoxin-related diseases. Herein, a dual-mode immunosensing platform based on self-fluorescent nanozyme was successfully constructed for the ultrasensitive detection of OTA. A porous spherical Fe₂O₃ nanozyme modified with an NH₂-BDC ligand (PS-NH₂-BDC@Fe₂O₃) was synthesized via a one-step hydrothermal method. This material not only exhibited high peroxidase (POD)-like activity due to its unique mesoporous structure and Fe²⁺/Fe³⁺ redox cycle, but also possessed self-fluorescent properties, thereby avoiding the introduction of exogenous fluorophores. Following a competitive immunoassay, the platform induced localized surface plasmon resonance (LSPR)-mediated multicolor changed in gold nanorods (Au NRs) via the H₂O₂/TMB reaction, while incorporating a ratiometric fluorescence system constructed from bovine serum albumin-templated gold nanoclusters (BSA-Au NCs) and PS-NH₂-BDC@Fe₂O₃-Ab₂ for dual-mode OTA detection. The developed immunosensor exhibited a wide linear range from 0.001 to 10 μg/L with a low detection limit of 2.2∗10^-4 μg/L. By combining intuitive multicolor visualization with self-calibrated dual-signal output, this work provides a novel and biocompatible sensing strategy for detecting trace mycotoxins in food.