Simple colorimetric detection of organophosphorus pesticides using naturally occurring extracellular vesicles

Abstract

Organophosphorus pesticides (OPs) are widely used in agriculture to eradicate insects. They, however, have raised public concern with respect to their potential impacts on human health. Here, a simple and sensitive colorimetric strategy was developed for the detection of OPs using acetylcholinesterase (AChE) in naturally occurring extracellular vesicles (EVs). To validate this strategy, the concentration of paraoxon as a representative OP was detected by measuring the colorimetric response in the dynamic range of 10−12–10−4 M, with a limit of detection (LOD) of 53.8 pM. Because EVs, which are composed of lipid bilayers, can provide a protective environment for AChE, the detection of OPs was highly reproducible without significant loss of AChE activity over a 30-day period. Furthermore, a spike-and-recovery experiment in human serum confirmed that despite impurities that may interfere with AChE activity, our EV-based AChE assay would be applicable for real samples in field detection. Importantly, our cost-effective, stable EV-based strategy enables a simple and sensitive OP detection without the expression/integration of AChE, formation of lipids, or encapsulation of AChE into liposomes. Thus, this strategy will offer new prospects for ensuring the safety of environmental and food samples with respect to contamination with various pesticides.