Regensburg 2016 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 18: Posters - DNA, RNA and Related Enzymes

BP 18.2: Poster

Montag, 7. März 2016, 17:30–19:30, Poster C

Single DNA Molecules and Colloids in a Thermophoretic Trap — •Tobias Thalheim, Marco Braun, Andreas Bregulla, and Frank Cichos — Molecular Nanophotonics Group, Institute of Experimental Physics I, University of Leipzig, Germany

We report on the trapping of single and multiple colloids as well as single DNA molecules in solution. We show, that the actual fuel of Brownian motion - temperature - is also capable of confining Brownian motion. A thermophoretic trap has been developed which employs temperature gradients, which are dynamically generated by the optical heating of a plasmonic structure. An optical feedback mechanism allows to control the number of colloids or molecules in the trap. The study of the motion of two colloids in the trap reveals not only the compression of the mean distance of the two particles in the trap but also a correlation of the spatial distribution of the particles inside the trapping region. The compression of the mean distance of the two colloidal particles suggests that also the macromolecular conformation of a single semiflexible polymer can be compressed by the action of the temperature gradients. First results of experiments on single lambda-DNA molecules provide evidence, that an inhomogeneous temperature profile is able to distort the conformation of the DNA, which paves the way for compression and free expansion experiments of single DNA molecules.