A lysosome-located and rhodamine-based fluorescence probe for recognizing hydrogen polysulfide.

Hydrogen polysulfide (HS, n≥2), as a kind of active sulfur species (RSS), has become a hot topic in RSS. It can regulate the biological activity of many proteins through S-sulfhydrylation of cysteine residues (protein Cys-SSH), and has a protective effect on cells. Although there have been some studies on hydrogen polysulfide, its production, degradation pathway and regulation mechanism still need further be researched. In presented study, an original lysosome-localized fluorescent probe for determining HS was developed utilizing rhodamine as the fluorogen. The probe used morpholine as the locating unit of lysosomes and chose 2-fluoro-5-nitrobenzoate as the recognizing group. Before adding HS, the proposed probe displayed a spironolactone structure and emitted very weak fluorescence. After adding HS, a conjugated xanthene was formed and the probe demonstrated green fluorescence. When the HS concentration was varied from 6.0×10 mol·L to 10.0×10 mol·L, the fluorescence intensity of the probe was linearly dependent on the HS concentration. And the detection limit was 1.5×10 mol·L. The presented probe owned a fast response speed, good selectivity, excellent sensitivity and broad pH work scope. In addition, the probe had been well utilized to sense endogenic and exogenic HS in lysosomes.