A novel phosphotriesterase hybrid nanoflower-hydrogel sensor equipped with a smartphone detector for real-time on-site monitoring of organophosphorus pesticides

Designing efficient and rapid methods for the detection of organophosphorus pesticides (OPs) residue is a prerequisite to mitigate their negative health impacts. In this study, we propose the concept of an enzyme catalysis system-based hydrogel kit integrated with a smartphone detector for in-field screening of OPs. Here, we rapidly prepared phosphotriesterase hybrid nanoflowers (PTE-HNFs) using a self-assembly strategy by adding external energy and embedded the nanocomposite in sodium alginate (SA) hydrogel to construct a target-responsive hydrogel kit. The color response of the kit is induced by catalyzing methyl parathion (MP) to produce p-nitrophenol. For on-site quantification, the color variations of the portable kit are converted into digital information through a smartphone, which exhibits an applicable linear range towards OPs. The hydrogel sensing platform demonstrates a wide linear range (1-150 μM) and low detection limit (0.15 μM) for MP while maintaining high reliability, excellent long-term stability, and ease of operation. Overall, the PTE-HNFs-based SA hydrogel kit provides a useful strategy for simple and sensitive detection of MP and holds great potential for applications in detecting OPs in food and environmental water.