Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 50: Plasmonics and Nanooptics V
O 50.8: Vortrag
Mittwoch, 16. März 2011, 16:45–17:00, WIL A317
Release of the fluorescent dye DAPI via photothermal dissociation of programmable DNA-gold-nanoparticle networks — •Malte Linn1, Anne Buchkremer2, Maximilian Reismann1, Ulrich Simon2, and Gero von Plessen1 — 1Inst. of Physics (IA), RWTH Aachen University, Germany — 2Institute of Inorganic Chemistry, RWTH Aachen University, Germany
The optical excitation of particle plasmons in gold nanospheres by means of laser light enables a highly localised and contact free heating of the nanoparticles and their immediate surroundings. This effect can be exploited to control temperature-sensitive biochemical reactions. In this work, it is used for the selective release of the DNA-intercalating fluorescent dye 4',6-diamidino-2-phenylindole (DAPI). Here, the release is realized via the photothermal dissociation of networks consisting of DNA-linked gold nanoparticles using focused cw-laser light (532 nm wavelength). Since the DAPI molecules only intercalate into DNA double strands, these molecules are released from the networks due to the photothermal controlled dehybridisation of the DNA into single strands. This process can be spectroscopically observed by measuring the fluorescence intensity, since the fluorescence of DAPI stored in the networks is suppressed by the nearby nanoparticles (fluorescence quenching). By using layer-by-layer networks, consisting of nanoparticles linked by different types of DNA, both a well-defined network structure and a step-by-step release of molecules can be realized. The principle shown here might be the basis for a remote release process of medical agents of future medicines.