Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 16: Poster Session I
BP 16.54: Poster
Dienstag, 27. März 2007, 17:00–19:30, Poster D
Improving the Functionality of DNA Layers on Gold by Electrically Induced Desorption — •Jelena Knežević1, Kenji Arinaga1,2, Ulrich Rant1, Erika Pringsheim1, Marc Tornow1, Shozo Fujita2, Naoki Yokoyama2, and Gerhard Abstreiter1 — 1Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching — 2Fujitsu Laboratories Ltd., 10-1 Morinosato-Wakamiya, Atsugi 243-0197, Japan
Self-assembled DNA layers on solid surfaces have been of great interest and widely introduced to various techniques for bio-molecular investigations. Recently, it has been recognized that the molecular packing density within the DNA layer crucially determines the functionality of the nucleic acids, for instance, the efficiency to hybridize to complementary targets. In this contribution, we describe a novel protocol to adjust the density of oligonucleotide layers by electrical means. At first a densely packed layer is immobilized onto a gold surface, in a second step, a fraction of the DNA molecules are desorbed from the surface by applying a series of electrochemical potentials. By monitoring steric interactions (hindrance) among the nucleic acids within the layer using optical means it is possible to evaluate the packing density in-situ and in real-time. We discuss several parameters which govern the desorption process (desorption potentials, DNA length, competitive adsorbents, etc.) and prove that the method allows a fine-tuning the DNA coverage. Finally, we demonstrate that layers prepared by electro-desorption retain their full bio-functionality by showing that dilute DNA layers exhibit hybridization efficiencies of approx. 100%.