Regensburg 2004 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 16: POSTER: Computational Physics, Complex Systems
CPP 16.34: Poster
Tuesday, March 9, 2004, 17:00–19:00, B
Fluorescence Lifetime Investigations of DNA mediated Dye/Gold Nanoparticle Conjugates — •M. Ringler1, E. Dulkeith1, T. Niedereichholz1, T. A. Klar1, and J. Feldmann1, A. Munoz-Javier2, and W. J. Parak2 — 1Photonics and Optoelectronics Group, University of Munich — 2CeNS, University of Munich
Gold nanoparticles have been shown to be extremely efficient
quenchers of luminescence from dye molecules attached to their
surface [1]. In the present study we investigated how the quenching
efficiency
depends on the distance between the dye molecule and the
nanoparticle using carbon chain spacers of different lengths.
An increase of the fluorescence lifetime with spacer length is
observed.
In a subsequent experiment we replaced the carbon spacers with
single stranded oligonucleotides (ssDNA). We can
spectroscopically determine the number of ssDNA bound to a
nanoparticle. Varying the degree of ssDNA coverage we observe that the
fluorescence lifetime becomes significantly longer
when the number of ssDNA per nanoparticle is increased. This gives evidence
that the conformation of DNA bound to gold
nanoparticles changes from wrapped to stretched when the surface
coverage is increased [2].
[1] E. Dulkeith et al., Phys. Rev. Lett. 89, 203002 (2002)
W. J. Parak et al., Nano Letters 3, 33-36 (2003)