A novel peptide-based fluorescence chemosensor for selective imaging of hydrogen sulfide both in living cells and zebrafish.

Hydrogen sulfide (H 2 S) plays an important role as a signaling compound (gasotransmitter) in living systems. However, the development of an efficient imaging chemosensor of H 2 S in live animals is a challenging field for chemists. Herein, a novel peptide-based fluorescence chemosensor L -Cu was designed and synthesized on the basis of the copper chelating with the peptide ligand (FITC–Ahx–Ser–Pro–Gly–His–NH 2 , L ), and its H 2 S sensing ability has been evaluated both in living cells and zebrafish. The peptide backbone and Cu 2+ -removal sensing mechanism are used to deliver rapid response time, high sensitivity, and good biocompatibility. After a fast fluorescence quench by Cu 2+ coordinated with L , the fluorescence of L is recovered by adding S 2− to form insoluble copper sulfide in aqueous solution with a detection limit for hydrogen sulfide measured to be 31 nM. Furthermore, the fluorescence chemosensor L -Cu showed excellent cell permeation and low biotoxicity to realize the intracellular biosensing, L -Cu has also been applied to image hydrogen sulfide in live zebrafish larvae. We expect that this peptide-based fluorescence chemosensor L -Cu can be used to study H 2 S-related chemical biology in physiological and pathological events. [ABSTRACT FROM AUTHOR]