MOF-Integrated Single-Enzymatic Colorimetric Paper-Based Biosensor for Point-of-Care Testing of Organophosphorus Pesticides
Jia‐Qi Huang, Yanfei Zhang, Huiwen Wang, Yuzhi Xu, Changqing Yi, Zong Dai, Si‐Yang Liu
Abstract
Organophosphorus pesticides (OPs), which are widely applied in agriculture, raise significant environmental and health concerns due to their neurotoxic inhibition of acetylcholinesterase (AChE). Conventional point-of-care testing (POCT) methods for OPs, which are essential for food and environmental safety, commonly rely on multiple enzymes to generate a colorimetric signal. By integrating AChE and a colorimetric reagent into a metal-organic framework (MOF)-based paper chip (AA@ZIF@Paper) and simplifying the detection mechanism to a single enzymatic reaction with peroxidase-like acetylcholine (ATCI, the substrate of AChE), a highly sensitive, selective, and stable paper chip for POCT of OPs was developed. AA@ZIF@Paper demonstrated a linear range of 0.5-50 μg/L for the detection of dichlorvos within 20 min, with a low limit of detection (LOD) of 0.29 μg/L (S/N = 3). The encapsulation of AChE by MOF improved pH, temperature, and long-term storage stability, and the innovative utilization of peroxidase-like ATCI eliminated the use of multiple enzymes that may complicate detection and hinder reproducibility. Furthermore, a 3D-printed device and a smartphone application were developed to further enhance convenience and accuracy. This MOF-integrated single-enzymatic paper chip achieved instrument-free, portable, and convenient POCT for OPs, providing a promising platform for food safety control as well as environmental monitoring.