In recent years, a number of research groups, including ours, have begun developing nanofabrication methods based on DNA self-assembly (1). DNA is an extraordinarily versatile material for designing nano-architectural motifs, due in large part to its programmable G-C and A-T base pairing into well-defined secondary structures. Although DNA nano-structures do not in themselves have useful electronic properties, the great value of patterned DNA nanostructures lies in their utility as scaffolds for organizing and positioning functional materials with nanometer scale precision. This approach holds enormous potential for designing “molecular printboards” whose complexity can rival that produced by lithographic methods.

Here we present our recent experimental progress to utilize novel DNA nanostructures for self-assembly as well as for templates in the fabrication of functional nano-patterned materials.  We have prototyped a new nanostructured DNA motif known as a cross structure (2). This nanostructure has a 4-fold symmetry which promotes its self-assembly into tetragonal 2D lattice. We have used the tetragonal 2D lattices to direct the self-assembly of proteins into periodical 2D nanoarrays (3). We have recently demonstrated the design and construction of fully addressable DNA tile nanogrids with each location bearing a unique biochemical label and used the array to detect single DNA hybridization (4). We have developed a modular approach to incorporate DNA aptamers into DNA nanostructures and used them to template the assembly of aptamer-binding proteins into periodical linear arrays (5). Our recent experiments on using 2D DNA lattice to template the self-assembly of nanoparticles provide clear evidence that DNA is  truly an excellent scaffold to organize nanoscale materials. We have used self-assembled DNA nanogrids to direct the self-assembly of 5 nm gold nanoparticles into periodic nanoarrays with accurate control of inter-particle spacings (6). Although there has been many previous examples of using rationally designed DNA tile structures to construct 1D or 2D periodic lattices, they lack control of the final lattice size because terminating events are not programmed into the self-assembly. Such control is crucial since future nanoelectronic devices assembled on a DNA based molecular print-board would require the DNA scaffolds to have defined boundaries, thus self-assembly of finite size DNA nanoarrays represents an immediate challenge for structural DNA nanotechnology. We have recently reported a novel and cost-effective strategy to produce finite size DNA arrays (7).

References:

1.H. Yan, Nucleic Acid Nanotechnology, Science, 306, 2048-2049 (2004).

2.H. Yan, S. H. Park, G. Finkelstein, J. H. Reif & T. H. LaBean, DNA templated Self-assembly

   of Protein Arrays and Highly Conductive Nanowires. Science 301, 1882 (2003).

3.S.H. Park, P. Yin, Y. Liu, J. Reif, T. H. LaBean, H. Yan, Programmable DNA Self-assemblies

   for Nanoscale Organization of Ligands and Proteins. Nano Lett  729, (2005).

4.K. Lund, Y. Liu, S. Lindsay, H. Yan, Self-assembling Molecular Pegboard, J. Am. Chem. Soc.

   127, 17606-17607 (2005).

5.Y. Liu, C.X. Lin, H. Li, H. Yan Aptamer directed Self-assembly of Proteins on a DANN

   Nanostructure, Angew. Chem. Int. Ed. 44, 4333 (2005).

6. J. Sharma, R. Chhabra, Y. Liu, Y. Ke, H. Yan, DNA templated self-assembly of two

   dimensional and periodical gold nanoparticle arrays, Angew. Chem. Int. Ed. 45 730-735 (2006)

7.Y. Liu, Y. Ke, H. Yan, Self-assembly of symmetric finite size DNA nanoarrays, J. Am. Chem.

   Soc. 127,  17140-17141 (2005).