A simple highly selective probe for discriminative visualization of endogenous cysteine, homocysteine and glutathione in living cells via three separated fluorescence channels.

Biothiols, as basic biological reactive sulfur species, perform vital actions in many critical physiological processes. Simultaneous detection and direct visualization of intracellular biothiols has great significance to figure out their metabolic mechanisms and cellular functions in living organism. However, it is an enormous challenge to selectively sense biothiols, troubled by their similar chemical structures and properties. In this work, we reported a novel chlorinated coumarin based multi-signal fluorescent probe (CC) for discriminative detection of cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) through three different emission channels. CC exhibited favorable sensing properties towards biothiols such as large fluorescence enhancement, low limits of detection (6, 3 and 200 nM for Cys, Hcy and GSH), fast response speed (15 min) and pretty good water solubility. Moreover, it was also utilized for discriminative visualization of endogenous and exogenous Cys, Hcy and GSH in A375 cells and Tcam-2 cells successfully.