A dual-reaction-site and dual-channel fluorescent-on probe for selectively monitoring mitochondrial glutathione

Glutathione (GSH) is the most abundant endogenous antioxidant and serves critical cellular functions in living system. As a results, it is of great significant to disclose GSH-specific fluorescent probe to deeply understand its biological functions. In this study, we developed a dual-reaction-site and dual-channel turn-on fluorescent probe Cyan-S-Nap for GSH by installing the sensing groups of thiophenol and sulfonamide moieties into the dyes of heptamethine cyanine and naphthalimide, respectively. The probe displayed selective response to GSH by the two independent fluorescent channels in visible (λem = 492 nm) and near-infrared (λem = 810 nm) regions. The dual emissions feature endows the probe with the ability to precisely detect the concentration fluctuation of GSH. In addition, the biological utilities of Cyan-S-Nap suggested that the probe was capable of imaging mitochondrial GSH in dual channels in a synchronous and independent manner, as well as monitoring the changes of GSH levels modulated by exogenous/endogenous reactive oxygen species in living cells and zebrafish.