title: A Family of Potent Ru(II) Photosensitizers with Enhanced DNA Intercalation: Bimodal Photokillers.
abstract: A new family of Ru(II)-based photosensitizers was synthesized and systematically characterized. The ligands employed to coordinate the ruthenium metal center were the commercially available 2,2'-bipyridine and a pyridine-quinoline hybrid bearing an anthracene moiety. The complexes obtained carry either PF6- or Cl(-) counterions. These counterions determine the complexes' hydrophobic or hydrophilic character, respectively, therefore dictating their solubility in biologically related media. All photosensitizers exhibit characteristic, relatively strong and wide UV-Vis absorption spectral profiles. Their high efficiency in generating cytotoxic singlet oxygen was established (up to ΦΔ ~0.8). Moreover, the interaction of these photosensitizers with double-stranded DNA was studied fluoro- and photospectroscopically and their binding affinities were found to be of the order of 3 × 10(7)  M(-1) . All complexes are photocytotoxic to DU145 human prostate cancer cells. The highest light-induced toxicity was conferred by the photosensitizers bearing Cl(-) counterions, probably due to the looser ionic "chaperoning" of Cl(-) , in comparison to PF6-, leading to higher cell internalization.
authors.affiliation: Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Athens, Greece.
authors.forename: Eleftherios K
authors.initials: EK
authors.lastname: Pefkianakis
authors.affiliation: Institute of Cancer Research, Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway.
authors.forename: Theodossis A
authors.initials: TA
authors.lastname: Theodossiou
authors.affiliation: Laboratory of Cellular Immunology, Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece.
authors.forename: Dimitra K
authors.initials: DK
authors.lastname: Toubanaki
authors.affiliation: Laboratory of Cellular Immunology, Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece.
authors.forename: Evdokia
authors.initials: E
authors.lastname: Karagouni
authors.affiliation: Division of Physical Chemistry, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Aghia Paraskevi, Greece.
authors.forename: Polycarpos
authors.initials: P
authors.lastname: Falaras
authors.affiliation: Division of Physical Chemistry, Institute of Nanoscience and Nanotechnology, NCSR Demokritos, Aghia Paraskevi, Greece.
authors.forename: Kyriakos
authors.initials: K
authors.lastname: Papadopoulos
authors.affiliation: Laboratory of Organic Chemistry, Department of Chemistry, University of Athens, Athens, Greece.
authors.forename: Georgios C
authors.initials: GC
authors.lastname: Vougioukalakis
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry / Q000633:toxicity*; D004247:DNA / Q000737:chemistry*; D006801:Humans; D008024:Ligands; D008027:Light; D008297:Male; D017319:Photosensitizing Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000633:toxicity; D011471:Prostatic Neoplasms / Q000188:drug therapy; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D017319:Photosensitizing Agents; D012428:Ruthenium; D004247:DNA