Development of Cholinesterase-Activatable Fluorescent Probes for Pesticide Residue Detection

The two main types of cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), share similar structures and functions and are commonly present in biological environments. The activity of cholinesterase is closely related to pesticide residues; it is crucial to develop enzyme-inhibition-based fluorescent probes for pesticide residue detection. However, the discovery of a fluorescent probe that selectively targets one of these is consistently a formidable challenge. In this study, two kinds of fluorescent probes, HBT-A and HBT-B, were developed with 2-(2-hydroxyphenyl) benzothiazole (HBT) as the fluorophore, which can selectively distinguish AChE and BChE, respectively. Our probes (HBT-A for AChE and HBT-B for BChE) exhibited high sensitivity and specificity toward their respective analytes in cells and zebrafish. Finally, we used HBT-B as an example and demonstrated that it can be an effective tool for visualizing pesticide residues in living organisms, highlighting the potential application of the developed probes in environmental monitoring and food safety.