AVS 53rd International Symposium
    Nucleic Acids at Surfaces Topical Conference Monday Sessions
       Session DN-MoA

Paper DN-MoA1
Counter Ion Free DNA Monolayers - Is It Possible?

Monday, November 13, 2006, 2:00 pm, Room 2014

Session: Nucleic Acids at Surfaces II
Presenter: A. Vilan, Weizmann Institute of Science, Israel
Authors: A. Vilan, Weizmann Institute of Science, Israel
D. Peled, Weizmann Institute of Science, Israel
S. Guha Ray, Weizmann Institute of Science, Israel
S. Daube, Weizmann Institute of Science, Israel
H. Cohen, Weizmann Institute of Science, Israel
R. Naaman, Weizmann Institute of Science, Israel
Correspondent: Click to Email
It is a common knowledge that the phosphate groups of DNA are negatively charged and hence balanced by counter ions. However, using XPS we find very small amounts of cations (e.g., Na, Mg) in compact DNA monolayers self-assembled on gold, with no net charge accumulation. This remarkable observation is studied for single and double strand DNA prepared from different buffer solutions. The counter ion concentration is found to systematically decrease under improving monolayer quality, suggesting that the system gains energy by replacing the original counter ions with protons. Discussion of the experimental evidences and possible implications to naturally packed DNA properties will be given. @FootnoteText@ This research was partially supported by the Grand Center.