A near-infrared fluorescent probe for imaging of endogenous hydrogen sulfide in living cells and mice

As one kind of most important of gaseous signal molecule, hydrogen sulfide plays a significantly role in the processes of physiology and pathology. Therefore, the research on hydrogen sulfide and its related enzymes such as cystathionine-β-synthase (CBS), 3-mercaptoacetic acid thiotransferase (3MST) and cystathionine-γ-lyase (CGL) is very meaningful. In this work, a novel fluorescent probe HCB-BT was developed, which containing a hemicyanidin conjugated with benzothiazole unit though unsaturated olefinic bond as fluorophore and a 2,4-dinitrobenzenesulfonate unit as recognition group to detecting the hydrogen sulfide. The dinitrobenzenesulfonate unit quenches the fluorescence of HCB-BT by intramolecular charge transfer (ICT) process. In the presence of hydrogen sulfide, the fluorescence emission was switched on by spliting the 2,4-dinitrobenzenesulfonyl unit. The recognition mode was verified by nuclear magnetic titration and high-resolution mass spectrometry. Furthermore, the probe HCB-BT was successfully applied to detect endogenous hydrogen sulfide in living cells and mice. This probe will help uncover more physiological and pathological mysteries related to hydrogen sulfide.