Bioplatform for Detecting Organophosphorus Compound Exposure

Abstract

This article presents results from The Plant Biomarker Challenge, an initiative funded by the Organization for the Prohibition of Chemical Weapons. The proposed platform—a plant species and measurement methodology—distinguishes between unexposed plants and those exposed to chlorpyrifos, a model organophosphorus pesticide. These compounds are active ingredients in pesticides and chemical warfare agents. Plants expressing acetylcholinesterase activity are affected by such compounds and can serve as biomarkers for accidental or criminal exposures, which is the focus of this study. An electrochemical method is proposed to assess pesticide exposure by analyzing alterations in acetylcholinesterase enzymatic activity. Initial assays in aqueous phase validate the mechanism, complemented by infrared spectrometry, before transitioning to plant samples. Chicory extracts exposed to varying chlorpyrifos concentrations are analyzed, enabling differentiation between nonexposed plants and those subjected to doses exceeding one-tenth of the manufacturer’s recommended mean dose. Electrochemical impedance spectroscopy evaluates acetylcholinesterase activity indirectly via its reaction with acetylthiocholine chloride and the subsequent interaction between generated thiocholine and silver nanoparticles. This comprehensive system integrates plant species and a measurement method to detect environments exposed to organophosphates.