(158f) Programming Self-Assembly of Plasmonic Nanomaterials with Sequence-Controlled DNA Polymers

DNA origami – a DNA-based polymer – has been generally considered as a powerful tool to achieve the self-assembly of inorganic plasmonic nanocrystals due to its high programmability and addressability. However, the assembly strategies developed so far are mostly limited to two sub-categories: i) non-finite lattice whose final dimension and shape cannot be controlled and ii) small-scale finite structures with typically only 2-10 nanocrystals. Moreover, in both types of plasmonic nanocrystal-DNA origami hybridization systems mentioned above, the plasmonic nanocrystals are only partially connected to the origami, which limits the number of addressable functionalization sites associated with each nanocrystal. Here we report a new strategy for programmable assembly of gold nanorods that can be assembled into a finite lattice with high tunability in their final configuration. The assembly of the nanorods is achieved using a simple rectangular DNA origami. The nanorods were first “wrapped” by the origami, and these wrapped nanorods were then assembled into finite lattice with desired 2D/3D configuration based on the pre-designed extension sequence position on the origami rectangles. By adjusting the dimension of the origami, or the length and sequence of the extensions, we could correspondingly adjust the size of the assembly unit, their interspacing, and the assembly pattern. Since almost the whole surface area of the nanorod is covered by the origami, these nanorods becomes more programmable due to a larger area of possible functionalization sites. Moreover, since the electric field enhancement is proportional to the particle size, the larger nanorods applied in the current study could greatly enhance their hotspot effect upon assembly. The well-defined configuration and enhanced hot-spot effect makes this nanorod assembly promising in a variety of fields including Surface Enhanced Ramen Spectroscopy (SERS), plasmonic photocatalysis, and plasmonic-enhanced luminescence.