DNA-nanoparticle superlattices formed from anisotropic building blocks

Directional bonding interactions in solid-state atomic lattices dictate the unique symmetries of atomic crystals, resulting in a diverse and complex assortment of three-dimensional structures that exhibit a wide variety of material properties. Methods to create analogous nanoparticle superlattices are beginning to be realized(1-5), but the concept of anisotropy is still largely underdeveloped in most particle assembly schemes(6). Some examples provide interesting methods to take advantage of anisotropic effects(7-11), but most are able to make only small clusters or lattices that are limited in crystallinity and especially in lattice parameter programmability(12-17). Anisotropic nanoparticles can be used to impart directional bonding interactions on the nanoscale(6,18), both through face-selective functionalization of the particle with recognition elements to introduce the concept of valency(19-21), and through anisotropic interactions resulting from particle shape(13,22). In this work, we examine the concept of inherent shape-directed crystallization in the context of DNA-mediated nanoparticle assembly. Importantly, we show how the anisotropy of these particles can be used to synthesize one-, two-and three-dimensional structures that cannot be made through the assembly of spherical particles.