A red-emission fluorescence probe based on 1,4-addition reaction mechanism for the detection of biothiols in vitro and in vivo

In this work, a new fluorescence probe ( DC ) with a donor–π–acceptor (D–π–A) structure was designed and synthesized for the detection of three kinds of biothiols (Cys, Hcy and GSH) in live cells and organisms. DC displayed an intense red-emission centered at 625 nm. In the presence of biothiols, the nucleophilic addition reaction between the C=C double bond of DC and the sulfhydryl group (–SH) of biothiols occurred, resulting in obvious fluorescence quenching responses. DC exhibited high selectivity towards biothiols over other common bioactive species with low detection limits (0.26, 0.43, and 0.44 µM for Cys, Hcy and GSH, respectively). In addition, DC displayed a rapid response to biothiols within 4 min. The applications of DC in biothiols detection and imaging were then successfully demonstrated for the real-time monitoring of endogenous and exogenous biothiols in live cells and live animals. Graphical abstract