Visualizing hydrogen sulfide in living cells and zebrafish using a red-emitting fluorescent probe via selenium-sulfur exchange reaction.

Hydrogen sulfide (H2S) is an important endogenous gasotransmitter and has been implicated with a variety of biological processes. The development of an efficient method for monitor H2S fluctuations in biological systems is of great significance to understand its roles in physiological and pathological conditions. In this work, two red-emitting fluorescent probes SNARF-SSPy and SNARF-SeSPy for H2S detection with turn-on fluorescence signals were reported. Interestingly, SNARF-SeSPy exhibited excellent anti-interference via dual selenium-sulfur exchange reaction even in the presence of high concentrations of thiols, whereas SNARF-SSPy did not sense H2S in the same condition. Additionally, in the present of H2S, SNARF-SeSPy showed a rapid response and excellent sensitivity with a detection limit of 34 nM. Most importantly, SNARF-SeSPy featured low cytotoxicity and could be employed to detect and image exogenous/endogenous H2S in living cells and zebrafish.