Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: POSTERS Micro- and Nanofluidics

CPP 22.18: Poster

Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A

Thermal fluctuation of single DNA-molecules and their dynamic in shear flow — Katrin Günther, •Kristin Laube, and Michael Mertig — Max-Bergmann-Zentrum für Biomaterialien, Budapester Str. 27, D-01069 Dresden, Germany

We investigate thermal fluctuations and dynamic behaviour of single λ-DNA-molecules tethered in a microfluidic cell in the dependence of cation concentration and shear rate. By the use of endspecifically attached fluorescent quantum dots instead of fluorescent dyes we do not change natural mechanical properties of the DNA and we are able to track a particular segment of the molecule. From thermal fluctuations we determine persistence lengths and therewith the 3D distribution of end-to-end-distance by simulations that take the tethering surface into account. In shear flow with different γ we specify fractional extensions and the amplitude of fluctuations indicating changes in the molecule’s morphology. For smaller shear rates we verify theoretically predicted cyclic motion of the free end of the DNA-molecule.