title: Photobleaching of asymmetric cyanines used for fluorescence imaging of single DNA molecules.
abstract: The photobleaching of the cyanine dyes YO and YOYO has been investigated for both free and DNA-bound dyes, using absorption and fluorescence spectroscopy coupled with fluorescence microscopy. For the free dyes, the nature of the reactive species involved in the photodegradation process is different for the monomer and the dimer, as shown by scavenger studies. For DNA-bound dyes, photoinduced fading of the visible absorption band occurs by different pathways depending on the drug binding mode and can be attenuated by appropriate scavengers. However, none of these scavengers were found to have any significant effect on the photobleaching of dye fluorescence. It appears that the reduction of fluorescence intensity comes from a quenching of the dye fluorescence by modified DNA bases, possibly 8-oxo-7,8-dihydro-2'-deoxyguanosine.
authors.affiliation: Department of Physical Chemistry, Chalmers University of Technology, S-412 96 Göteborg, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Kanony
authors.forename: B
authors.initials: B
authors.lastname: Akerman
authors.forename: E
authors.initials: E
authors.lastname: Tuite
mesh_terms: D000818:Animals; D001583:Benzoxazoles / Q000737:chemistry / Q000528:radiation effects; D002417:Cattle; D003090:Coliphages / Q000235:genetics; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D003839:Deoxyadenosines / Q000737:chemistry / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004587:Electrophoresis, Agar Gel; D005456:Fluorescent Dyes / Q000737:chemistry / Q000528:radiation effects; D009682:Magnetic Resonance Spectroscopy; D008856:Microscopy, Fluorescence / Q000379:methods; D008958:Models, Molecular; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010782:Photolysis; D011806:Quinolinium Compounds / Q000737:chemistry / Q000528:radiation effects; D013050:Spectrometry, Fluorescence / Q000379:methods; D013057:Spectrum Analysis; D013950:Thymus Gland; D013997:Time Factors
chemical_list: D001583:Benzoxazoles; D003839:Deoxyadenosines; D005456:Fluorescent Dyes; D011806:Quinolinium Compounds; C075296:1,1'-((4,4,7,7-tetramethyl)-4,7-diazaundecamethylene)bis-4-(3-methyl-2,3-dihydro(benzo-1,3-oxazole)-2-methylidene)quinolinium; C089813:YO-PRO 1; C078251:2'-deoxy-7,8-dihydro-8-oxoadenosine; D004247:DNA