(143b) Formation of Complex Metal Nanostructures By Imprinting Full-Site Addressability from DNA Origami Onto Inorganic Particles

DNA origami – a DNA-based polymer – has been generally considered as a powerful biomaterial 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 nanocrystals (spherical particles, rods, and cubes) that can be assembled into multiple complex configurations that are hard to achieve using traditional methods. The assembly of the gold nanocrystals is achieved using a simple rectangular DNA origami. The nanocrystals were first “wrapped” by the origami based on the particle-origami interaction. These wrapped crystals were then assembled into finite lattice with desired configuration through pre-designed single-stranded DNA extensions on the origami rectangles. By adjusting the sequence and position of the extensions, we could correspondingly adjust their assembly patterns. Since almost the whole surface area of the nanocrystals is covered by the origami, these structures distinguish themselves from the previous origami-particle hybridizations through their full-site addressability. Moreover, since the electric field enhancement is proportional to the particle size, the larger nanoparticles applied in the current study could greatly enhance their hotspot effect upon assembly. The well-defined configuration and enhanced hot-spot effect makes this assembly promising in a variety of fields including Surface Enhanced Ramen Spectroscopy (SERS), plasmonic photocatalysis, and plasmonic-enhanced luminescence.