Highly selective and sensitive detection of hydrogen sulfide in aqueous medium and live cells using peptide-based bioprobe to mimic the binding sites of the ceruloplasmin for Cu(II) ions.

Hydrogen sulfide (H2S) plays a vital role in biological systems, so it is important to develop new methods for monitoring H2S with high selectively and sensitivity. In this study, we report the efficient solid phase synthesis of a new peptide-based bioprobe L that mimics the Cu(II) binding sites of ceruloplasmin. L exhibits highly sensitive colorimetric and fluorescent "turn off" responses to Cu2+ with high selectively among various metal ions over a broad pH range in 100% aqueous solutions. Interestingly, as a new promising analytical bioprobe, the L-Cu ensemble can monitor H2S by both colorimetric and fluorescent changes, and the limit of detection (LOD) is found to be as low as 14.7 nM. The reversibility experiment indicated that L could be recycled many times as reversible bioprobe. It is worth noting that L could be used to detect Cu2+ and H2S specifically in two real samples. Moreover, L exhibited excellent water-solubility and low biotoxicity even at high concentrations based on MTT study, and cell imaging results indicated that it can be applied to detecting Cu(II) and H2S in living RKO cells monitored by confocal fluorescence microscopy imaging.