Rational design of a reversible fluorescent probe for sensing GSH in mitochondria.

Glutathione (GSH) is the most abundant biological thiol in cells. It can participate in metabolic processes, regulate the body's oxidation level and is essential for various cell functions. An abnormal concentration of glutathione in the cell is directly related to some diseases. Therefore, it is very important to develop fast, sensitive and reversible detection methods for GSH. Herein, we designed a reversible fluorescent probe (named GeP) for sensing GSH based on the nucleophilic addition and dissociation of intracellular GSH to GeP. The probe GeP showed a fast response time and a 20-fold fluorescence change toward GSH. It exhibited excellent mitochondrial-targeted performance and could be used to monitor GSH in mitochondria. Importantly, GeP could also enable superresolution fluorescence imaging of mitochondria through stochastic optical reconstruction microscopy.