A near-infrared fluorescent probe for detecting hydrogen sulfide with high selectivity in cells and ulcerative colitis in mice.

Although hydrogen sulfide (H 2 S) is a well-known toxic gas, its vital role as a gas transmitter in various physiological and pathological processes of living systems cannot be ignored. Relevant investigations indicate that endogenous H 2 S is involved in the development of ulcerative colitis pathology and is overexpressed in ulcerative colitis, and hence can be considered as an ulcerative colitis biomarker. Herein, an isophorone-xanthene-based NIR fluorescent probe (IX-H 2 S) was constructed to image H 2 S. Owing to its large conjugated structure, the probe exhibits a near-infrared emission wavelength of 770 nm with a large Stokes shift (186 nm). Moreover, IX-H 2 S has excellent selectivity for the detection of H 2 S without interference from other analytes including thiols. In addition, the probe has been successfully applied not only in fluorescence imaging of endogenous and exogenous H 2 S in living cells, but also in imaging of H 2 S in normal and ulcerative colitis mice. Encouraged by the eminent performance, IX-H 2 S is expected to be a potent "assistant" for the diagnosis of ulcerative colitis.