Fast‐Response Turn‐on Fluorescent Probes Based on Thiolysis of NBD Amine for H 2 S Bioimaging

Hydrogen sulfide (H 2 S) 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 H 2 S 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 H 2 S over other biologically relevant species. The fluorescein‐NBD‐based probe showed 65‐fold green fluorescent increase upon H 2 S activation. The rhodamine‐NBD‐based probe reacted rapidly with H 2 S ( t 1/2 ≈1 min) to give a 4.5‐fold increase in red fluorescence. Moreover, both probes were successfully used for monitoring H 2 S in living cells and in mice. Based on such probe‐based tools, we could observe H 2 O 2 ‐induced H 2 S biogenesis in a concentration‐dependent and time‐dependent fashion in living cells.