Fluorometric and colorimetric analysis of carbamate pesticide via enzyme-triggered decomposition of Gold nanoclusters-anchored MnO2 nanocomposite

In this work, we designed a multi-signal readout platform for sensitive monitoring carbamate pesticide based on gold nanoclusters-anchored MnO2 (AuNCs-MnO2) nanocomposite. The fluorescence of AuNCs was quenched by MnO2 via Förster resonance energy transfer effect. In the presence of acetylcholinesterase and choline oxidase, the substrate acetylcholine (ACh) is catalyzed to generate H2O2 that can specially induce the decomposition of MnO2, coupling with change of color and recovery of fluorescence. Carbamate pesticide as an inhibitor of acetylcholinesterase prevent the generation of H2O2, further block the breakage of MnO2, which caused the fluorescence switch. Such color and fluorescence respond can be utilized for highly sensitive carbamate pesticide identification and quantification. Under the optimum conditions, the dual-output assay possessed good sensitivity for rapid detection of carbaryl (model analyte) with a detection limit of 0.125 μg L−1. The fluorometric/colorimetric bimodal platform showed good stability and anti-interference ability comparing to that of others enzyme-based sensor.