An iminocoumarin benzothiazole-based fluorescent probe for imaging hydrogen sulfide in living cells

Hydrogen sulfide (H₂S) has recently been identified as the third gaseous signaling molecule that is involved in regulating many important cellular processes. We report herein a novel fluorescent probe for detecting H₂S based on iminocoumarin benzothiazole scaffold. The probe displayed high sensitivity and around 80-fold increment in fluorescence signal after reacting with H₂S under physiological condition. The fluorescent intensity of the probe was linearly related to H₂S concentration in the range of 0-100 μM with a detection limit of 0.15 μM (3σ/slope). The probe also showed excellent selectivity towards H₂S over other biologically relevant species, including ROS, RSS and RNS. Its selectivity for H₂S is 32 folds higher than other reactive sulfur species. Furthermore, the probe has been applied for imaging H₂S in living cells. Cell imaging experiments demonstrated that the probe is cell-permeable and can be used to monitor the alteration of H₂S concentrations in living cells. We envisage that this probe can provide useful tools to further elucidate the biological roles of H₂S.