Berlin 2005 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 85: Biosensors and Biohybrid Systems

AKB 85.3: Vortrag

Mittwoch, 9. März 2005, 13:00–13:15, TU H2013

Time Resolved Dynamics of Electrically Switched Oligonucleotides on Au Surfaces — •Ulrich Rant¹, Kenji Arinaga^1,2, Yong Woon Kim¹, Shozo Fujita², Naoki Yokoyama², Roland Netz¹, Gerhard Abstreiter¹, and Marc Tornow¹ — ¹Technische Universitaet Muenchen, 85748 Garching, Germany — ²Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-0197, Japan

Macromolecules grafted to surfaces have been receiving considerable attention lately due to their interesting and complex behaviour at interfaces, but also in terms of applications (e.g., DNA sensors). In particular, the use of electrically addressable substrates permits many possibilities for manipulating charged molecules, which is accompanied by novel insights into interactions between the surface and the tethered polyelectrolytes. Recently, we reported on the dynamic manipulation of DNA on Au surfaces by electrically switching the strands while observing their orientations by optical means. Here we present time resolved experiments in which we study surface-tethered oligonucleotides of different lengths (24 and 48mer) in their single as well as double stranded conformation. We elucidate the dynamics of the molecules as they are repelled from, or attracted to the biased surface when reversing the charge on the metal substrate. By comparing the experimental data to hydrodynamic simulations, we are able to identify a distinctly different behaviour for single and double stranded DNA, respectively. Possibly, the identified mechanisms are of fundamental nature for the electrical manipulation of charged polymers with markedly dissimilar mechanical flexibilities.