Regensburg 2004 – wissenschaftliches Programm
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SYLS: Life Sciences on the Nanometer Scale - Physics Meets Biology
SYLS 4: Symposium "Life Sciences on the Nanometer Scale - Physics Meets Biology"
SYLS 4.5: Vortrag
Donnerstag, 11. März 2004, 10:45–11:00, H 37
Electro-Manipulation of Oligonucleotides Tethered to Au-Surfaces — •Ulrich Rant1, Kenji Arinaga1,2, Shozo Fujita2, Naoki Yokoyama2, Gerhard Abstreiter1, and Marc Tornow1 — 1Walter Schottky Institut, Technische Universitaet Muenchen, 85748 Garching, Germany — 2Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-0197, Japan
We present electro-optical investigations of short DNA strands, tethered to Au-electrodes in aqueous solutions. By controlling the bias potential at the supporting electrodes, we are able to study multiple phenomena related to electrostatic interactions between polyelectrolytes and metal interfaces in electrolyte environment:
DNA-desorption at highly negative electrode potentials can be utilized to study the electrostatic nature of DNA, revealing a new regime of excessive counterion condensation in solutions of high salt concentrations. In contrast, by employing moderate AC-potentials with respect to the potential of zero charge, we are able to attain persistent conformational switching with formidable long term stability of the DNA layer on the Au-surface, alternating the orientation of the strands between a lying and a standing state. We elucidate the capability of the presented modulation experiments to provide information on collective monolayer properties such as steric interactions between adsorbed molecules, as well as the possibilities to study molecular dynamics of tethered DNA subjected to electric fields at the metal/solution interface.