A super sensitive fluorescent probe for imaging endogenous hydrogen sulfide in living cells

Hydrogen sulfide (H2S) that typically performs biphasic biological functions in organisms plays an opposite role at the concentrations above or below normal level of the organism. Therefore, it is significant to develop a fluorescent probe with high sensitivity and selectivity and rapid response for the detection of hydrogen sulfide in vivo. The work describes the design and biological applications of a novel turn-on fluorescence probe SS-N3 in which the quinoline quaternary ammonium salt derivative is introduced as the fluorescent skeleton and azide is employed as the detection group of H2S. The probe SS-N3 shows strong fluorescence at 610 nm, as the azide group is reduced to an amino group by H2S. The probe SS-N3 shows high selectivity to H2S than other anions and some biological mercaptans, and strong anti-interference capacity. In addition, the probe SS-N3 exhibits little cytotoxicity, improved photostability and large Stokes shift (135 nm), as well as can be effectively used as an indicator of H2S level in living cells.