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Intracellular Photophysics of an Osmium Complex bearing an Oligothiophene Extended Ligand |
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| Authors: | Kilian R A Schneider Avinash Chettri Houston D Cole Dr Katharina Reglinski Jannik Brückmann John A Roque III Dr Anne Stumper Dr Djawed Nauroozi Dr Sylvia Schmid Dr Christoffer B Lagerholm Prof Dr Sven Rau Prof Dr Peter Bäuerle Prof Dr Christian Eggeling Dr Colin G Cameron Prof Dr Sherri A McFarland Prof Dr Benjamin Dietzek |
| Institution: | 1. Department Functional Interfaces (K.R.A.S., A.C., B.D.), Department Biophysical Imaging (K.R., C.E.), Leibniz Institute of Photonic Technology (IPHT) e. V., Albert-Einstein-Straße 9, 07745 Jena, Germany
Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller-University Jena, Helmholtzweg 4, 07743 Jena, Germany;2. Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019-0065 USA;3. Department Functional Interfaces (K.R.A.S., A.C., B.D.), Department Biophysical Imaging (K.R., C.E.), Leibniz Institute of Photonic Technology (IPHT) e. V., Albert-Einstein-Straße 9, 07745 Jena, Germany Institute of Applied Optic and Biophysics, Friedrich-Schiller University Jena, Max-Wien-Platz 1, 07743 Jena, Germany University Hospital Jena, Bachstraße 18, 07743 Jena, Germany;4. Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany;5. Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019-0065 USA Department of Chemistry and Biochemistry, The University of North Carolina at Greensboro, Greensboro, North Carolina, 27402 USA;6. Institute of Organic Chemistry II and Advanced Materials, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany;7. <8. MRC Human Immunology Unit & Wolfson Imaging Center Oxford, Headley Way, Oxford, OX3 9DS UK;9. Department Functional Interfaces (K.R.A.S., A.C., B.D.), Department Biophysical Imaging (K.R., C.E.), Leibniz Institute of Photonic Technology (IPHT) e. V., Albert-Einstein-Straße 9, 07745 Jena, Germany Institute of Applied Optic and Biophysics, Friedrich-Schiller University Jena, Max-Wien-Platz 1, 07743 Jena, Germany <10. Department Functional Interfaces (K.R.A.S., A.C., B.D.), Department Biophysical Imaging (K.R., C.E.), Leibniz Institute of Photonic Technology (IPHT) e. V., Albert-Einstein-Straße 9, 07745 Jena, Germany |
| Abstract: | This contribution describes the excited-state properties of an Osmium-complex when taken up into human cells. The complex 1 Os(bpy)2(IP-4T)](PF6)2 with bpy=2,2′-bipyridine and IP-4T=2-{5′-3′,4′-diethyl-(2,2′-bithien-5-yl)]-3,4-diethyl-2,2′-bithiophene}imidazo4,5-f]1,10]phenanthroline) can be discussed as a candidate for photodynamic therapy in the biological red/NIR window. The complex is taken up by MCF7 cells and localizes rather homogeneously within in the cytoplasm. To detail the sub-ns photophysics of 1 , comparative transient absorption measurements were carried out in different solvents to derive a model of the photoinduced processes. Key to rationalize the excited-state relaxation is a long-lived 3ILCT state associated with the oligothiophene chain. This model was then tested with the complex internalized into MCF7 cells, since the intracellular environment has long been suspected to take big influence on the excited state properties. In our study of 1 in cells, we were able to show that, though the overall model remained the same, the excited-state dynamics are affected strongly by the intracellular environment. Our study represents the first in depth correlation towards ex-vivo and in vivo ultrafast spectroscopy for a possible photodrug. |
| Keywords: | in vitro spectroscopy oligothiophene osmium polypyridyl transient absorption ultrafast spectroscopy |