title: Two-photon induced fluorescence of Cy5-DNA in buffer solution and on silver island films.
abstract: We report the observation of a strong two-photon induced fluorescence emission of Cy5-DNA within the tunable range of a Ti:Sapphire laser. The estimated two-photon cross-section for Cy5-DNA of 400GM is about 3.5-fold higher than it was reported for rhodamine B. The fundamental anisotropies of Cy5-DNA are close to the theoretical limits of 2/5 and 4/7 for one- and two-photon excitation, respectively. We also observed an enhanced two-photon induced fluorescence (TPIF) of Cy5-DNA deposited on silver island films (SIFs). In the presence of SIFs, the TPIF is about 100-fold brighter. The brightness increase of Cy5-DNA TPIF near SIFs is mostly due to enhanced local field.
authors.affiliation: Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland at Baltimore, 725 West Lombard Street, Baltimore, MD 21201, USA. joanna@cfs.umbi.umd.edu
authors.forename: Joanna
authors.initials: J
authors.lastname: Lukomska
authors.forename: Ignacy
authors.initials: I
authors.lastname: Gryczynski
authors.forename: Joanna
authors.initials: J
authors.lastname: Malicka
authors.forename: Slawomir
authors.initials: S
authors.lastname: Makowiec
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Lakowicz
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Gryczynski
mesh_terms: D002021:Buffers; D002232:Carbocyanines; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004247:DNA / Q000032:analysis* / Q000737:chemistry*; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry*; D013194:Staining and Labeling / Q000379:methods
chemical_list: D002021:Buffers; D002232:Carbocyanines; D020099:Coated Materials, Biocompatible; C089187:cyanine dye 3; C085321:cyanine dye 5; D012834:Silver; D004247:DNA