Fast-Response Turn-on Fluorescent Probes Based on Thiolysis of NBD Amine for H2S Bioimaging

Hydrogen sulfide (H2S) is an important endogenous signaling molecule with multiple biological functions. New selective fluorescent turn-on probes based on fast thiolyling of NBD (7-nitro-1,2,3-benzoxadiazole) amine were explored for sensing H2S in aqueous buffer and in living cells. The syntheses of both probes are simple and quite straightforward. The probes are highly sensitive and selective toward H2S over other biologically relevant species. The fluorescein-NBD-based probe showed 65-fold green fluorescent increase upon H2S activation. The rhodamine-NBD-based probe reacted rapidly with H2S (t(1/2) approximate to 1 min) to give a 4.5-fold increase in red fluorescence. Moreover, both probes were successfully used for monitoring H2S in living cells and in mice. Based on such probe-based tools, we could observe H2O2-induced H2S biogenesis in a concentration-dependent and time-dependent fashion in living cells.