Huang_2025_Food.Chem_496_146732

Precise and reliable monitoring of organophosphate pesticide residues plays a critical role in safeguarding public health and environmental equilibrium. We investigated different types of DNAs with Cu-hemin and developed a G-quadruplex (G4)-regulated MOF nanozyme method. The catalytic performance of Cu-hemin@G4 nanostructures demonstrated a 11-fold enhancement in peroxidase (POD) activity over isolated Cu-hemin MOF, achieving efficient conversion of 3,3',5,5'-tetramethylbenzidine (TMB) chromogenic substrate into blue-colored oxidized derivatives. Acetylcholinesterase (AChE) and acetylcholine (ATCh) inhibited this activity, but organophosphate pesticides (OPs) restored it through enzymatic interaction. On the basis of G-quadruplex-regulated mimic enzyme activity, the proposed colorimetric method realized quantitative methyl parathion determination ranging from 0.005 microg L(-1) to 0.4 microg L(-1) with an ultra-low detection limit of 0.975 ng L(-1). The research develops rational strategies for constructing high-performance nanozymes, advances nanozyme-based biosensors for OPs detection, and offers efficient solutions for pesticide detection in agro-ecological applications.