DNA-nanoparticle superlattices formed from anisotropic building blocks

Abstract

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, but the concept of anisotropy is still largely underdeveloped in most particle assembly schemes. Some examples provide interesting methods to take advantage of anisotropic effects, but most are able to make only small clusters or lattices that are limited in crystallinity and especially in lattice parameter programmability. Anisotropic nanoparticles can be used to impart directional bonding interactions on the nanoscale, both through face-selective functionalization of the particle with recognition elements to introduce the concept of valency, and through anisotropic interactions resulting from particle shape. 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.

Nanoparticle Superlattices: The Roles of Soft Ligands

“…It is virtually impossible to probe complex temperature‐dependent nanoparticle crystallization in aqueous buffered environments with other techniques. Synchrotron‐based SAXS could provide important information on lattice structures, lattice constants, crystal sizes, etc.,44, 45, 148 which helps formulation of DNA‐based design rules 53…”

Polygamous particles

“…Identical particles coated with identical DNA strands can be joined together by adding to the suspension a linker strand that attaches to the two coatings (9,10). Such structures have been used for immunoassays (11), particle aggregation, and formation of crystalline structures, typically Face Centered Cubic (FCC) (12).…”

Importance of the DNA “bond” in programmable nanoparticle crystallization

“…In these systems, however, the identity of the atom and its bonding behavior cannot be independently controlled, limiting our ability to tune material properties at will. In contrast, when a nanoparticle is modified with a dense shell of upright, oriented DNA, it can behave as a programmable atom equivalent (PAE) (1, 2) that can be used to synthesize diverse crystal structures with independent control over composition, scale, and lattice symmetry (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). The thermodynamic product of this crystallization process has been extensively studied by both experimental and theoretical means, and thus a series of design rules has been proposed and validated with a simple geometric model known as the complementary contact model (CCM).…”