Book of Abstracts: Albany 2007
June 19-23 2007
Assembling Nanocomponents One by One with DNA
One of the central challenges of nanoscience is the organization of functional components according to a deliberately designed pattern, and the ability to modify this pattern at will. Because of its molecular recognition specificity and structural features, DNA presents a unique opportunity to address the above goal. Our research group has been examining the creation of branched DNA molecules containing organic and inorganic vertices, and the study of their self-assembly into discrete, as well as extended DNA nanostructures. By using these hybrid DNA-synthetic molecules, we hope to combine the structural directionality that can be obtained from rigid small molecules, as well as their intrinsic properties, such as luminescence and redox activity, with the programmability of DNA. Specifically, we show the sequential and selective self-assembly of a cyclic hexagon containing double stranded DNA arms and rigid organic vertices. We use this method to selectively construct a hexagon of gold nanoparticles, by labeling each particle with a DNA-containing molecule, which serves to dictate its ultimate location within the final construct (Figure 1). Gold nanoparticle assemblies have recently emerged as a promising class of materials with novel optical, electronic, catalytic and sensing applications. Many of their properties, such as electron transport and optical coupling, arise directly from the relative arrangement of the nanoparticles within the assembly. However, fundamental studies of these phenomena have been hampered by the lack of methods to systematically assemble nanoparticles into well-defined discrete model structures (1).
We also report a straightforward method to selectively organize gold nanoparticles into libraries of discrete and well-defined structures, using a small number of single-stranded, dynamic DNA templates. This approach not only provides the ability to finely control the geometry of the assembly, and the precise position of each nanoparticle, but it also allows the modification and tuning of these structural features after the assembly. As such, the resulting nanoparticle groupings can undergo structural switching and write/erase functions with specific external agents (Figure 2). Access to libraries of precisely positioned particle groupings will allow for the systematic examination of their optical, electronic and catalytic properties as a function of structure, and will lead to advances in the use of these particles as components of nanoelectronic and nanophotonic circuitry, as plasmonic tools, and as surface-enhanced Raman scattering (SERS) substrates. (2)
Department of Chemistry,
References and Footnotes
Figure 1: Gold Nanoparticle-DNA Hexagon. DNA molecules with rigid organic vertices can provide gold nanoparticles with an exact ?address? that dictates their final location in a well-defined assembly. For more information on the DNA mediated organization of six gold nanoparticles into a cyclic hexameric structure, visit the poster station and read the references below.
Figure 2: Single stranded DNA templates (left) for the dynamic construction of discrete gold nanoparticle assemblies (right).