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

Although hydrogen sulfide (HS) 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 HS 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-HS) was constructed to image HS. 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-HS has excellent selectivity for the detection of HS without interference from other analytes including thiols. In addition, the probe has been successfully applied not only in fluorescence imaging of endogenous and exogenous HS in living cells, but also in imaging of HS in normal and ulcerative colitis mice. Encouraged by the eminent performance, IX-HS is expected to be a potent "assistant" for the diagnosis of ulcerative colitis.