Two-photon induced fluorescence of Cy5-DNA in buffer solution and on silver island films

Biochem Biophys Res Commun. 2005 Mar 4;328(1):78-84. doi: 10.1016/j.bbrc.2004.12.148.

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.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Validation Study

MeSH terms

  • Buffers
  • Carbocyanines*
  • Coated Materials, Biocompatible / chemistry
  • DNA / analysis*
  • DNA / chemistry*
  • Microscopy, Fluorescence, Multiphoton / methods*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Silver / chemistry*
  • Staining and Labeling / methods

Substances

  • Buffers
  • Carbocyanines
  • Coated Materials, Biocompatible
  • cyanine dye 3
  • cyanine dye 5
  • Silver
  • DNA