Fluorescent sensor for rapid detection of organophosphate pesticides using recombinant carboxylesterase PvCarE1 and glutathione-stabilized gold nanoclusters

Considering the severe threat to human health posed by organophosphate pesticides (OPs), reliable and rapid detection methods are urgently needed. In this study, we developed a straightforward and sensitive fluorescence sensor for OP detection. The sensor is based on glutathione-stabilized gold nanoclusters (GSH-AuNCs) and the inhibition of the recombinant carboxylesterase PvCarE1. The fluorescence signal of GSH-AuNCs is efficiently quenched by p-nitrophenol (p-NP) through inner filter effect, which is the product of the recombinant carboxylesterase PvCarE1-catalyzed hydrolysis of p-nitrophenol acetate (p-NPA). In the presence of OPs, the activity of the recombinant carboxylesterase PvCarE1 is inhibited, resulting in decreased p-NP production, and the fluorescence signal of the GSH-AuNCs is maintained. The assay exhibited good sensitivity to dichlorvos, trichlorfon, and profenofos, with detection limits of 0.2 μg/L, 5 μg/L, and 5 μg/L, respectively. In addition, the developed assay was applied to apple sample detection, with recoveries ranging from 84.5 % to 106.3 % and RSDs ranging from 1.3 % to 10.5 %, demonstrating its high potential in monitoring OPs in food.