Peptide-based ratiometric fluorescent probe for highly selective detection of Cd (II) and its application in bioimaging

This work reported a new peptide fluorescent probe L including dansyl group (acceptor) and tryptophan (donor) via imitated the binding sites of natural protein. L exhibited exclusively selective ratiometric fluorescence response towards Cd2+ ions over other metal ions based on fluorescent resonance energy transfer (FRET) effects. As designed, L showed exciting sensitivity to Cd2+ ions in aqueous media, and the detection limits are less than 27.5 nM. In addition, the binding pattern of L and Cd2+ was confirmed by fluorescence titration analysis which was found to be 2:1 and further it was confirmed by Job's plot. What' more, L exhibited very low biotoxicity and exciting cell infiltration, and have been successfully used for fluorescence imaging of Cd2+ ions in living HeLa cells.