Nuclear targeting terpyridine iron(II) complexes for cellular imaging and remarkable photocytotoxicity

Basu, Uttara and Khan, Imran and Koley, Debasis and Saha, Sounik and Kondaiah, Paturu and Chakravarty, Akhil R (2012) Nuclear targeting terpyridine iron(II) complexes for cellular imaging and remarkable photocytotoxicity. In: JOURNAL OF INORGANIC BIOCHEMISTRY, 116 . pp. 77-87.

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Abstract

Iron(II) complexes Fe(L)(2)](2+) as perchlorate (1-3) and chloride (1a-3a) salts, where L is 4'-phenyl-2,2':6',2 `'-terpyridine (phtpy in 1, 1a), 4'-(9-anthracenyl)-2,2':6',2 `'-terpyridine (antpy in 2, 2a) and 4'-(1-pyrenyl)-2,2':6',2 `'-terpyridine (pytpy in 3, 3a), were prepared and their photocytotoxicity studied. The diamagnetic complexes 1-3 having an FeN6 core showed an Fe(III)-Fe(II) redox couple near 1.0 V vs. saturated calomel electrode in MeCN-0.1 M tetrabutylammonium perchlorate. Complexes 2 and 3, in addition, displayed a quasi-reversible ligand-based redox process near 0.0 V. The redox and spectral properties are rationalized from the theoretical studies. The complexes bind to DNA in a partial intercalative mode. The pytpy complex efficiently photo-cleaves DNA in green light via superoxide and hydroxyl radical formation. The antpy and pytpy complexes exhibited a remarkable photocytotoxic effect in HeLa cancer cells (IC50, similar to 9 mu M) in visible light (400-700 nm), while remaining essentially nontoxic in dark (IC50, similar to 90 mu M). Formation of reactive oxygen species (ROS) inside the HeLa cells was evidenced from the fluorescence enhancement of dichlorofluorescein upon treatment with the pytpy complex followed by photo-exposure. The antpy and pytpy complexes were used for cellular imaging. Confocal imaging and dual staining study using propidium iodide (PI) showed nuclear localization of the complexes. (c) 2012 Elsevier Inc. All rights reserved.

Item Type:	Journal Article
Publication:	JOURNAL OF INORGANIC BIOCHEMISTRY
Publisher:	ELSEVIER SCIENCE INC
Additional Information:	Copyright for this article belongs to ELSEVIER SCIENCE INC, NEW YORK
Keywords:	Iron;Terpyridine derivatives;DNA intercalator;Photocytotoxicity;Cellular imaging;DFT calculations
Department/Centre:	Division of Biological Sciences > Molecular Reproduction, Development & Genetics Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	16 Dec 2012 10:07
Last Modified:	16 Dec 2012 10:07
URI:	http://eprints.iisc.ac.in/id/eprint/45552

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