Chung Hang J . Choi , Joshua I . Cutler , and

In the assembly and crystallization of nanoparticles into ordered lattices, DNA is a powerful structure-directing ligand because its programmability allows for a priori control over the lattice symmetries and lattice constants of the nanoparticle superstructures. [ 1–8 ] Practically, however, characterization and processing of superlattices made from DNA-modifi ed particles is limited because the morphology and programmability of these structures exhibited in solution are either distorted or lost entirely when they are removed from their assembly medium (aqueous saline solution). Because these superlattices are held together via cooperative DNA duplexes, they rapidly collapse or dissociate where these interactions are unfavorable, such as in distilled water, in common organic solvents, at high temperatures, or under vacuum. Therefore, the development of a method for improving the mechanical stability and solution processability of the nanoparticle lattices is a necessary step as studies of these materials shift from understanding the parameters that govern their assembly to pursuing fundamental properties and useful applications. [ 9–11 ] In this work, we report a method for stabilizing DNA-assembled three-dimensional superlattices in the solid state by silica encapsulation, where both the symmetries and lattice spacings of the solution-phase lattices are preserved. Once encapsulated, superlattice morphologies are no longer dictated by DNA interactions, and as such remain stable against distortion, collapse, or dissociation under many previously inaccessible conditions. Silica encapsulation is a technique commonly used to stabilize inorganic nanoparticles of varying chemical compositions and morphologies against aggregation or oxidation. [ 12–17 ]