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Phosphorescent sensor for biological mobile zinc

Title
Phosphorescent sensor for biological mobile zinc
Authors
You Y.Lee S.Kim T.Ohkubo K.Chae W.-S.Fukuzumi S.Jhon G.-J.Nam W.Lippard S.J.
Ewha Authors
전길자남원우유영민Shunichi Fukuzumi
SCOPUS Author ID
전길자scopus; 남원우scopus; 유영민scopus; Shunichi Fukuzumiscopus
Issue Date
2011
Journal Title
Journal of the American Chemical Society
ISSN
0002-7863JCR Link
Citation
vol. 133, no. 45, pp. 18328 - 18342
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
A new phosphorescent zinc sensor (ZIrF) was constructed, based on an Ir(III) complex bearing two 2-(2,4-difluorophenyl)pyridine (dfppy) cyclometalating ligands and a neutral 1,10-phenanthroline (phen) ligand. A zinc-specific di(2-picolyl)amine (DPA) receptor was introduced at the 4-position of the phen ligand via a methylene linker. The cationic Ir(III) complex exhibited dual phosphorescence bands in CH 3CN solutions originating from blue and yellow emission of the dfppy and phen ligands, respectively. Zinc coordination selectively enhanced the latter, affording a phosphorescence ratiometric response. Electrochemical techniques, quantum chemical calculations, and steady-state and femtosecond spectroscopy were employed to establish a photophysical mechanism for this phosphorescence response. The studies revealed that zinc coordination perturbs nonemissive processes of photoinduced electron transfer and intraligand charge-transfer transition occurring between DPA and phen. ZIrF can detect zinc ions in a reversible and selective manner in buffered solution (pH 7.0, 25 mM PIPES) with K d = 11 nM and pK a = 4.16. Enhanced signal-to-noise ratios were achieved by time-gated acquisition of long-lived phosphorescence signals. The sensor was applied to image biological free zinc ions in live A549 cells by confocal laser scanning microscopy. A fluorescence lifetime imaging microscope detected an increase in photoluminescence lifetime for zinc-treated A549 cells as compared to controls. ZIrF is the first successful phosphorescent sensor that detects zinc ions in biological samples. © 2011 American Chemical Society.
DOI
10.1021/ja207163r
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자연과학대학 > 화학·나노과학전공 > Journal papers
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