Metal–Organic Framework-Based Cascade Catalysis-Enabled Fluorescent ELISA with Higher Enzymatic Stability for Zearalenone Detection in Maize

The enzyme-linked immunosorbent assay (ELISA) stands as one of the most frequently employed rapid detection techniques for both chemical and biological contaminants. Horseradish peroxidase (HRP) and hydrogen peroxide (H₂O₂), serving as signal generators, play indispensable roles throughout the entire ELISA process. However, HRP and H₂O₂ exhibit high sensitivity to elevated temperatures, hindering the broader utilization and transportation of ELISA. Hereby, being inspired by the cascade catalysis of glucose by glucose oxidase (GOx) and HRP as well as the advantageous properties of metal-organic frameworks (MOFs), we developed a cascade catalysis-based competitive fluorescent ELISA (CCF-ELISA) for mycotoxin detection in maize using zearalenone (ZEN) as a model. The results revealed the remarkable protective effects of MOFs on enzymatic activities. Based on upon characteristics, the built CCF-ELISA enabled the detection of ZEN with a half-maximal inhibitory concentration of 0.54 ng/mL and allowed a detection range from 0.19 to 1.51 ng/mL. When applied to naturally contaminated maize samples, the outcomes obtained from the CCF-ELISA showed a high level of comparability with high-performance liquid chromatography-tandem mass spectrometry, demonstrating the promising potential of the developed CCF-ELISA in the rapid detection for food security.