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

Paper DN-MoM6
Engineering DNA-DNA Surface Interactions

Monday, November 13, 2006, 9:40 am, Room 2014

Session: Nucleic Acids at Surfaces I
Presenter: P.E. Laibinis, Vanderbilt University
Authors: P.E. Laibinis, Vanderbilt University
M. Bajaj, Massachusetts Institute of Technology
I.H. Lee, Massachusetts Institute of Technology
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The selectivity provided by DNA base pairing provides a general strategy for ultimately programming the self-assembly of smaller building block components into larger functional units with specified hierarchical structures. We have developed methods for immobilizing DNA strands to surfaces with controlled structures and at controlled densities for fundamental studies of DNA hybridization. These studies focus on optimizing DNA hybridization events so to maximize interaction energies between species. By systematically varying the surface density of oligonucleotides, we have established the optimal surfaces for selective DNA adsorption, both as free DNA molecules and as species themselves localized on the surface of gold nanoparticles. These optima are different. We have also explored the ability to perform orthogonal supra-particular assembly by generating particles that expose silica and gold surfaces, each of which was selectively functionalized to expose a different DNA sequence on their surfaces. This orthogonal DNA-directed assembly was confirmed by confocal microscopy of the microspheres. These bifacial particles can be selectively functionalized by the adsorption of their respective DNA complements with goals of directing the assembly of complex structures based on these "Janus" particle building blocks. Efforts toward increasing complexity include the development of a trifacial particle that will also be discussed.