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

Department of Biochemistry and Molecular Biology , University of Maryland, Baltimore, Baltimore, Maryland, United States
Biochemical and Biophysical Research Communications (Impact Factor: 2.3). 04/2005; 328(1):78-84. DOI: 10.1016/j.bbrc.2004.12.148
Source: PubMed


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.

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