MOF-engineered CuO nanozymes with boosted peroxidase-like activity for colorimetric-fluorescent dual-mode detection of deoxynivalenol.

The development of a high sensitivity biosensor for the detection of highly toxic deoxynivalenol (DON) is vital for human health and food security. In this work, by integrating metal-organic frameworks (MOF) with cubic CuO nanoparticles (CuO@MOF), the nanocomposite achieved a 4.8-fold increase in specific surface area compared to pristine CuO, which synergistically enhanced its peroxidase-like (POD) activity through optimized substrate affinity and accelerated charge transfer. Consequently, based on the marriage properties of POD activity and fluorescence signal from CuO@MOF nanoparticles and carbon dots (CDs), a colorimentric-fluorescent dual-mode biosensor was constructed for DON detection. Concurrently, the competitive binding of DON with immobilized antigens on CuO@MOF-CDs results in antibody displacement, leading to progressive reduction of captured probes with increasing DON concentrations, thereby inducing proportional attenuation in both colorimetric and fluorescence signal intensities. Under the optimum conditions, the established biosensor achieved a detection limit of 0.0018 ng/mL for DON. Furthermore, the prepared dual-mode biosensor was successfully applied to detect DON in tap water, wheat and corn, demonstrating its practical utility for real-world applications. Overall, this work not only advances nanozyme design through MOF-mediated interface engineering but also provides a rapid, accurate, and field-deployable strategy for monitoring mycotoxins in complex matrices.