A retrievable and highly selective peptide-based fluorescent probe for detection of Cd2+ and Cys in aqueous solutions and live cells

摘要

A novel dansyl-tetrapeptide fluorescent probe (L) for the continuous fluorescent "off-on-off" response detection of Cd2+ ions and Cysteine (Cys) has been designed and synthesized. In our approach, L exhibited very high selectivity to Cd2+ ions over other common metal ions in buffer aqueous solution at natural pH. The resulting L-Cd binding motif system could continuously detect Cys among Glutathione (GSH), Homocysteine (HCy) and 20 natural amino acids. The excellent reversibility and cyclicity of L were also confirmed during the detection of Cd2+ ions and Cys. The detection limit of Cd2+ ions and Cys were obtained to be 93 nM and 35 nM, and lower than EPA and WHO guidelines. What's more, L showed low cytotoxicity and exciting cell infiltration toward living cells, which successfully fluorescent "off-on-off" biological imaged Cd2+ ions and Cys effectively in HeLa cells and renal tubule epithelium (HK2) cells by confocal fluorescence imaging. This study will promote the development of novel multifunctional peptide-based fluorescent probe for Cd2+ ions and Cys in environmental and biological systems.