title: "Switched-on" flexible chalcogenopyrylium photosensitizers. Changes in photophysical properties upon binding to DNA.
abstract: 2,4-Bis(4-dimethylaminophenyl)-6-alkylthiopyrylium and selenopyrylium dyes are essentially nonfluorescent (phi F < 0.001) and are poor generators of singlet oxygen in aqueous solution. However, upon complexation to calf thymus DNA, quantum yields for both fluorescence and generation of singlet oxygen increased dramatically. Irradiation of the dye-DNA complexes produced strand breaks in the DNA. The photodamage is not observed in the absence of oxygen and is suppressed by the addition of the singlet oxygen quencher imidazole. The inactivation of the pseudo-rabies virus upon treatment of oxygenated leukodepleted 20% hematocrit red blood cell suspensions with the chalcogenopyrylium dyes and light followed the same trend observed with quantum yields for the generation of singlet oxygen in the dye-DNA complexes.
authors.affiliation: Institute for Lasers, Photonics, and Biophotonics, Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA.
authors.forename: Tymish Y
authors.initials: TY
authors.lastname: Ohulchanskyy
authors.forename: Michael K
authors.initials: MK
authors.lastname: Gannon
authors.forename: Mao
authors.initials: M
authors.lastname: Ye
authors.forename: Andrey
authors.initials: A
authors.lastname: Skripchenko
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wagner
authors.forename: Paras N
authors.initials: PN
authors.lastname: Prasad
authors.forename: Michael R
authors.initials: MR
authors.lastname: Detty
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry* / Q000378:metabolism; D004396:Coloring Agents / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D016566:Organoselenium Compounds / Q000737:chemistry*; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000378:metabolism; D018036:Selenium Compounds / Q000737:chemistry* / Q000378:metabolism; D026082:Singlet Oxygen / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013057:Spectrum Analysis; D013876:Thiophenes / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000814:Aniline Compounds; D004396:Coloring Agents; D016566:Organoselenium Compounds; D017319:Photosensitizing Agents; D018036:Selenium Compounds; D012996:Solutions; D013876:Thiophenes; C493773:selenopyrylium chloride; C521680:thiopyrylium; D026082:Singlet Oxygen; D004247:DNA