Fluorescent probe for detecting hydrogen sulfide based on disulfide nucleophilic substitution-addition

In view of the importance of hydrogen sulfide (H2S) in the organism, a fast, noninvasive method for the detection of H2S in situ is needed. Fluorescent probes based on disulfide-bond nucleophilic substitution-addition can selectively detect H2S in vivo, which is very popular because it allows quick response for H2S, thus it will be a useful tool for monitoring H2S in the vivo. We developed a dicyanoisopentanone-based H2S fluorescent probe (EW-H) that used a disulfide group as a self-destructive linker reaction site. Under the nucleophilic substitution of H2S, the disulfide bond of EW-H was cleaved, and then nucleophilic addition took place intramolecularly to release the fluorophore (at 580 nm). The response to H2S, EW-H had high sensitivity (86 nM of the detection limit), large Stokes shift (155 nm) and a fast response time. More importantly, the probe was also applied for bioimaging in HepG2 cells, indicating its potential applications in biological organism.