A reversible turn-on fluorescent probe for quantitative imaging and dynamic monitoring of cellular glutathione

Real-time quantification of glutathione (GSH) concentrations in living cells is essential for understanding GSH-related pathological events. However, most existing fluorescent probes are not suitable for this purpose due to their irreversible response mechanisms. Only a few probes have been successfully developed to realize this goal to date. Herein, we presented a fluorescent probe (QG-S) for quantifying cellular GSH and monitoring GSH dynamic variations. The probe QG-S was successfully employed in real-time monitoring of the dynamic variations of GSH in living cells upon reversible treatment with a GSH inhibitor (N-methylmaleimide) by using confocal microscopy. Moreover, the probe QG-S showed extremely low cytotoxicity and was facilely used to quantitatively determine the GSH concentration (4.25 mM) in living HeLa cells.