Detection of Organophosphorus Pesticides Using Silver-Coated Gold Nanoparticles

Plasmonic nanoparticles can provide great utility for the construction of advanced optical and electrical sensors. Herein, we present a versatile sensing strategy that can perform triple-mode detection of organophosphorus pesticides (OPPs) based on carbon dots (CDs)-participated silver deposition on gold nanoparticles (AuNPs). Simply, a hybrid system composed of AuNPs, CDs, and silver ions in phosphate-buffered saline (AuNPs/Ag+/CDs) is designed, and alkaline phosphatase (ALP) is used to catalytically produce l-ascorbic acid, which reduces silver ions to metallic silver on the surface of AuNPs. OPPs can simultaneously modulate triple optical signals, including light absorption, fluorescence, and Rayleigh scattering of the AuNPs/Ag+/CDs hybrid, by inhibiting the activity of ALP, and thus colorimetry, fluorescence, and resonance Rayleigh scattering methods for OPPs are established. Meanwhile, the mechanism of spectral change involved in the three optical signals is investigated in detail. In addition, the proposed detection system is used for the determination of OPPs in vegetables with satisfactory results. The nanohybrid-platform-integrated triple-signal readout provides not only approaches for OPPs detection but also insight for the development of optical sensors.