Ultrafast response fluorescent probe with red-emission for monitoring hydrogen sulfide in vivo and in vitro

A NIR fluorescent probe AZ-NO2 for hydrogen sulfide was designed and synthesized through simple method, which employs dicyanoisophorone based fluorescent dye as a fluorophore and 2,4-dinitrophenyl ether moiety as the specific reaction site. Owing to the H2S-induced efficient thiolysis of dinitrophenyl ether, the probe displayed excellent selectivity toward H2S, a low detection limit of 16.3 nM, a large Stokes shift (185 nm) and an ultrafast response time (75 s). In addition, the sensing mechanism was investigated via mass spectra. Finally, in view of its favourable biocompatibility, the probe AZ-NO2 has been successfully applied to the fluorescent bioimaging of H2S in HepG2 cells and zebrafish.