AVS 51st International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI2-WeM

Paper BI2-WeM8
Coverage and Stability of ssDNA on Gold: Effects of Temperature and Displacement by Alkanethiols

Wednesday, November 17, 2004, 10:40 am, Room 213C

Session: Oligo Nucleotide - Surface Interactions
Presenter: L.J. Whitman, Naval Research Laboratory
Authors: D.Y. Petrovykh, University of Maryland and Naval Research Laboratory
A. Opdahl, National Institute of Standards and Technology
H. Kimura-Suda, National Institute of Standards and Technology
M.J. Tarlov, National Institute of Standards and Technology
L.J. Whitman, Naval Research Laboratory
Correspondent: Click to Email
We characterize self-assembled films of thiolated and unmodified single-stranded DNA (ssDNA) on polycrystalline Au films using Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy. We use homo-oligonucleotides to study the film stability as a function of the DNA-base under conditions used in hybridization experiments. One common method of controlling the ssDNA probe spacing and availability is post-deposition exposure to alkanethiols. Another common post-deposition treatment is exposure to buffer solution at elevated temperature during the hybridization step. In both cases, we find strong base-dependence in agreement with the previous results for film structure and relative adsorption affinities of thiol-modified and unmodified ssDNA [JACS 125, 5219 (2003); 125, 9014 (2003)]. The use of these post-deposition treatments also allows us to compare the relative effects of DNA-DNA vs. DNA-Au interactions for each of the bases. For the three bases that we examined, a wide range of DNA-DNA and DNA-Au interactions is observed: both interactions are weak for oligo(dT); oligo(dA) exhibits a strong affinity for Au surfaces but weak DNA-DNA interactions; and oligo(dC) represents the opposite case, with strong DNA-DNA but weak DNA-surface interactions.