Ratiometric Assays for Acetylcholinesterase Activity and Organo‐Phosphorous Pesticide Based on Superior Carbon Quantum Dots and BLGF‐Protected Gold Nanoclusters FRET Process

Abstract

AbstractA ratiometric fluorescence system is reported based on fluorescence resonance energy transfer (FRET) between carbon quantum dots (CQDs) and gold nanoclusters (Au NCs) for sensitive detection of acetylcholinesterase (AChE) and organophosphorus pesticides (OPPs). The CQDs and Au NCs were synthesized by one‐pot approach, emitting at 420 nm (λex=320 nm) and 680 nm (λex=500 nm) respectively. To verify the effect on CQDs−Au NCs of biothiols, the thiol sensing was performed by measuring the ratio of F680/F420 as the increasing of cysteine as model, which shows a low detection limit of 1.07 μmol L−1. Herein, this sensing system was employed to determine AChE activity depend on its hydrolysis for acetylcholine (ATCh) generated thiocholine. The AChE activity can be assayed as low as 1.08 mU mL−1 within a wide linear range from 3 to 50 mU mL−1 and evaluated in practical samples. In addition, a kind of organophosphorus pesticide, hypertoxic diazinon, was selected to efficiently inhibit the ATCh hydrolysis, and can be detected based on this proposed strategy. As far as we known, the proposed ratiometric assay system based on CQDs−Au NCs nanocomposites is the first time to demonstrate for AChE and OPPs assay. We believed that this promising strategy will opens up a novel pathway of using CQDs and Au NCs for the expanded biosensing applications.