A novel peptide fluorescent probe based on different fluorescence responses for detection of mercury species and hydrogen sulfide

Mercury species, including inorganic and organic mercury, are extremely harmful to organisms and the environment. Therefore, it is of great significance to rapidly and selectively detect and distinguish inorganic mercury ions and organic mercury. This study reports peptide sequences that can act as inorganic mercury ions and organic mercury ligands. The peptide fluorescent probe KEEP ((Dansyl-Glu-Glu)2-Lys-NH2) can detect mercury species by its coordination with the side chain of glutamic acid. Hg2+ can be detected by the "turn-off" fluorescence mode, while CH3Hg+ and PhHg+ can be detected by the "turn-on" fluorescence mode. This probe with different fluorescence response to inorganic and organic mercury is very rare, which makes it possible to distinguish between Hg2+, CH3Hg+ and PhHg+. KEEP-Hg2+ can also detect hydrogen sulfide (H2S) through fluorescence reproduction. KEEP can detect these three analytes without interference from other substances due to excellent selectivity. KEEP also has good biocompatibility and low biotoxicity, and can successfully monitor the accumulation of Hg2+ and S2- in living cells. This probe provides a new approach for the detection of inorganic mercury and organic mercury.