Zhou_2025_Food.Chem_500_147435

The extensive use of poisonous chlorpyrifos in agriculture has created an urgent need for reliable detection methods. In this study, a rationally designed heterogeneous metal-organic framework (MOF) nanozyme was developed, consisting of an Fe(3)O(4) core and a Cu(II)-centered zeolitic imidazolate framework shell (Fe@CuZIF) for chlorpyrifos analysis. The hybrid exhibited synergistic properties, including strong adsorption capacity, magnetic separation for chlorpyrifos enrichment, and enhanced oxidase-mimicking activity compared with Fe(3)O(4) without H(2)O(2). Leveraging the inhibitory effect of chlorpyrifos on the acetylcholinesterase- regulated collapse of Cu(II)-centered MOF shell, the Fe@CuZIF-based sensing platform produced chlorpyrifos-triggered oxidase-mimicking activity. The system achieved a detection limit of 0.35 ng mL(-1), along with excellent selectivity, anti-interference resistance, and capability for time-dependent kinetic monitoring of chlorpyrifos bioaccumulation in rice. Overall, this work establishes a promising paradigm for nanozyme-based sensors in pesticide residue analysis for food safety and provides a new strategy for designing hybrids capable of target pesticide-activated recognition.