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

A NIR fluorescent probe AZ-NO 2 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 H 2 S-induced efficient thiolysis of dinitrophenyl ether, the probe displayed excellent selectivity toward H 2 S, 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-NO 2 has been successfully applied to the fluorescent bioimaging of H 2 S in HepG2 cells and zebrafish.