A red-emitting fluorescent probe for sensing and imaging biothiols in living cells

As important members of biothiol species, cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) are involved in numerous physiological activities. Moreover, abnormal levels of these biothiols are closely relevant to a series of diseases. Therefore, it's of great importance and challenges to develop efficient approaches for sensitively detecting biothiols. Herein, a novel fluorescent probe JSC-RSH for sensing Cys/Hcy/GSH was reported. JSC-RSH exhibits excellent properties including red-emitting, high sensitivity and selectivity, as well as rapid response towards biothiols. The probe alone only emits negligible fluorescence, while a remarkable fluorescence emission in the red region could be observed in the presence of biothiols. The calculated limits of detection (LODs) for Cys/Hcy/GSH are 7.9 nM, 10.2 nM and 4.2 nM, respectively. Furthermore, probe JSC-RSH with low cytotoxicity was utilized for monitoring endogenous and exogenous biothiols in A549 cells.