A dual-emission turn-on fluorescent probe for specific detecting Cys/Hcy from GSH through thiol-chromene click reaction

A dual-emission fluorescent probe was developed for detecting biothiols, a coumarin-chromene scaffold. In this work, the sensing mechanism of probe BDU towards biothiols was through two different pathways. For Hcy and Cys, it went through a cascade reaction followed by an isomerization, which formed a salicylic carbonate structure and coumarin substance. While for GSH, only the nucleophilic reaction was carried out without further isomerization. The probe exhibits selectivity for Hcy/Cys (Em = 470 nm) and GSH (Em = 546 nm) in PBS buffer containing 0.5 % DMSO. Besides, this probe could effectively sense biothiols in vitro and in vivo with low detecting limits, fast responses, good biocompatibility, and low toxicity. With all these excellent properties, this probe exhibits great potential value for applications in biological study.