Green CuNA@Arg-Ce BioMOF with multi enzyme-like catalytic activities for self-cascade one-step colorimetric detection...

Biomimetic cascade systems have emerged as effective tools for signal amplification in sensing. In this work, a self-cascade one-step operation biosensor for colorimetric detection of zearalenone (ZEN) was constructed based on a biological metal-organic framework (BioMOF) CuNA@Arg-Ce, which was synthesized via a green self-assembly strategy using natural molecules as eco-friendly ligands. CuNA@Arg-Ce exhibits integrated phosphatase-, laccase-, and catalase-like activities as a self-cascade catalyst that hydrolyzed disodium phenyl phosphate (PPDS) to phenol, followed by the oxidation with O₂ decomposed from H₂O₂ and coupling with 4-aminoantipyrine to form red quinoneimine. ZEN selectively inhibited the phosphatase-like activity that generated a "signal-off" response. The rapid cascade biosensor exhibits a detection limit of 0.1568 μg L^-1 with high selectivity and good performance in multiple grain samples. Additionally, a smartphone-based RGB analysis enables rapid on-site detection. This study provides a strategy for designing BioMOF composites as self-cascade catalysts and offers an green platform for practical mycotoxin monitoring.