Reversible Fluorescent Probe for Highly Selective and Sensitive Detection of Mercapto Biomolecules

• Published in: Inorganic chemistry Vol. 50; no. 14; pp. 6543 - 6551
• Main Authors: Wu, Jiasheng, Sheng, Ruilong, Liu, Weimin, Wang, Pengfei, Ma, Jingjin, Zhang, Hongyan, Zhuang, Xiaoqing
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18.07.2011
• Subjects: Cells, Cultured; Coumarins - chemistry; Crystallography, X-Ray; Cysteine - analysis; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; Glutathione - analysis; HEK293 Cells; Homocysteine - analysis; Humans; Mercury - chemistry; Models, Molecular; Molecular Structure; Organomercury Compounds - chemical synthesis; Organomercury Compounds - chemistry; Particle Size; Stereoisomerism; Surface Properties
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic200181p

A coumarin-derived complex, Hg 2 L 2 , was reported as a highly sensitive and selective probe for the detection of mercapto biomolecules in aqueous solution. The addition of Cys to a 99% aqueous solution of Hg 2 L 2 resulted in rapid and remarkable fluorescence OFF–ON (emission at 525 nm) due to the ligand-exchange reaction of Cys with L coordinated to Hg2+. The increased fluorescence can be completely quenched by Hg2+ and recovered again by the subsequent addition of Cys. Such a fluorescence OFF–ON circle can be repeated at least 10 times by the alterative addition of Cys and Hg2+ to the solution of Hg 2 L 2 , indicating that it can be used as a convertible and reversible probe for the detection of Cys. The interconversion of Hg 2 L 2 and L via the decomplexation/complexation by the modulation of Cys/Hg2+ was definitely verified from their crystal structures. Other competitive amino acids without a thiol group cannot induce any fluorescence changes, implying that Hg 2 L 2 can selectively determine mercapto biomolecules. Using confocal fluorescence imaging, L/Hg 2 L 2 as a pair of reversible probes can be further applied to track and monitor the self-detoxification process of Hg2+ ions in SYS5 cells.