In Vivo Monitoring of Hydrogen Polysulfide via a NIR-Excitable Reversible Fluorescent Probe Based on Upconversion Luminescence Resonance Energy Transfer.

Hydrogen polysulfide (H2Sn), derived from hydrogen sulfide (H2S), has attracted increasing attention, which is suggested to be the actual signal molecule instead of H2S in physiological and pathological processes. Reversible detection of H2Sn through a NIR-excitable fluorescence probe is an effective means to understand its functions but is quite challenging. Herein, we reported a NIR-excitable ratiometric nanoprobe for the reversible detection of H2Sn based on luminescence resonance energy transfer principle with upconversion nanoparticles as the energy donor and an organic molecule, SiR1, as the energy acceptor and reversible recognition unit of H2Sn. The as-prepared nanoprobe exhibited high selectivity and fast response for the reversible detection of H2Sn, which can monitor the formation and consumption of endogenous H2Sn in living cells. Because of the reduced autofluorescence by NIR excitation, it was successfully applied for tracking the fluctuation of H2Sn concentration of mice in physiological and pathological processes including inflammation and liver injury.