Fe,Zr-MOF Nanozyme-Enhanced Dual-Recognition System: Integrating Molecularly Imprinted Polymers and Aptamers for Colorimetric Detection of Chlorpyrifos

Chlorpyrifos (CPF) poses severe environmental and health risks, driving the need for on-site monitoring tools. This study presents a novel dual-recognition colorimetric sensor for ultrasensitive detection of CPF by coimmobilizing molecularly imprinted polymers (MIPs) and aptamers onto bimetallic Fe,Zr-MOF composites. The resulting Fe,Zr-MOF/Apt/MIP hybrid synergistically merges the structural robustness of MIPs with the conformational specificity of aptamers, while also functioning as both a nanocarrier and a peroxidase mimic. Notably, CPF binding sterically hinders substrate diffusion to catalytic sites, enabling quantitative detection via dose-dependent inhibition of TMB oxidation. The optimized sensor exhibits exceptional performance: a broad linear range (1-120 ng mL⁻¹), ultralow detection limit (0.105 ng mL⁻¹), and high specificity against interferents. When validated with complex matrices (apples, pears, and cabbage), it achieved satisfactory recoveries (91.0-110.0%). This work establishes a field-deployable strategy for on-site pesticide monitoring in food and environmental safety.