Pore size-regulated MOF nanozyme-based colorimetric sensor array for rapid detection and classification of mycotoxins

The rapid and accurate discrimination of mycotoxins is a critical priority for food safety and agricultural monitoring. However, achieving the simultaneous, high-throughput screening of these complex targets remains a formidable challenge. Herein, a novel dual-substrate, six-channel colorimetric sensor array based on topology-engineered porphyrinic metal-organic framework nanozymes (PCN-Fe series) is developed for the rapid detection and classification of mycotoxin. By modulating the connectivity of Zr₆ nodes and TCPP(Fe) linkers, three nanozymes with tailored topologies, pore dimensions, and surface charges were successfully synthesized. The sensing array exploits substrate-dependent enzyme-mimicking activities driven by pore-regulated mass transfer kinetics (for TMB) and electrostatic enrichment (for ABTS) mechanisms. Furthermore, the differential adsorption of mycotoxins occludes the internal channels, modulating the residual catalytic activity of the surface Fe sites to generate multidimensional colorimetric signal patterns. By integrating linear discriminant analysis (LDA), the system achieved the successful identification and quantitative detection of six major mycotoxins with robust dose-dependent relationships (R² > 0.98) through a 2 h pre-incubation and a rapid 15 min colorimetric readout. Further evaluation in real samples validated the array's capability for the precise discrimination of both individual and mixed mycotoxins, achieving a classification accuracy exceeding 97.6%. This work presents a versatile and effective high-throughput analytical platform for the rapid screening of mycotoxins, highlighting its immense potential in food safety and quality control.