Instantaneous fluorescent probe for the specific detection of H2S

Novel cyanine-based fluorescent probes for the detection of H2S were developed. The probes developed are stable under physiological conditions. The water soluble fluorescent probe 2 displayed ultrafast and specific response to H2S displaying NIR fluorescence of 115-fold turn-on with the detection limit of 11 nM without assistance of organic solvent or surfactant. Cell imaging experiments indicated that probe 2 was cell-permeable and was able to detect H2S sensitively in lysosomes. Moreover, our probe was able to detect H2S intrinsically produced H2S through enzymatic/non-enzymatic biosynthetic pathway from Cys/GSH. Moreover, we applied probe 2 to detect H2S in living mice and demonstrated the fast metabolism of H2S. Thus, probe 2 shows great promise as a reporter for H2S.