A 3-(2′-nitro vinyl)-4-phenylselenyl coumarin as a fluorescent probe for distinguishing detection of Cys/Hcy and GSH

Biothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) play important roles in regulating the redox balance of life process and are closely associated with human health and diseases. In order to better understand their roles in physiological process and the early diagnosis of related diseases, it is crucial for the selective detection of biothiols in biological systems. In this paper, we developed a 4-phenylselenium coumarin-nitroolefin conjugate as the fluorescent probe for the detection of biothiols. By introducing the 4-phenyselenium as the active site, probe CouSeNO2 is capable of detecting Cys/Hcy and GSH in dual fluorescence channels. For the biothiols, the first-step sensing reaction is proved to be nucleophilic substitution of 4-phenylselenium by the thiol group. Furthermore, through two-channel fluorescence imaging, probe CouSeNO2 has been successfully applied to sense the exogenous and endogenous biothiols in living cells.