Switching binary states of nanoparticle superlattices and dimer clusters by DNA strands

Nanoscale components can be self-assembled into static three-dimensional structures 1 , 2 , 3 , 4 , 5 , 6 , arrays 7 , 8 , 9 and clusters 10 , 11 , 12 , 13 using biomolecular motifs. The structural plasticity of biomolecules and the reversibility of their interactions can also be used to make nanostructures that are dynamic, reconfigurable and responsive. DNA has emerged as an ideal biomolecular motif for making such nanostructures, partly because its versatile morphology permits in situ conformational changes using molecular stimuli 12 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 . This has allowed DNA nanostructures to exhibit reconfigurable topologies and mechanical movement 17 , 18 . Recently, researchers have begun to translate this approach to nanoparticle interfaces 18 , 23 , 24 , where, for example, the distances between nanoparticles can be modulated, resulting in a distance-dependent plasmonic response 18 , 23 , 25 . Here, we report the assembly of nanoparticles into three-dimensional superlattices and dimer clusters, using a reconfigurable DNA device that acts as an interparticle linkage. The interparticle distances in the superlattices and clusters can be modified, while preserving structural integrity, by adding molecular stimuli (simple DNA strands) after the self-assembly processes has been completed. Both systems were found to switch between two distinct rigid states, but a transition to a flexible device configuration within a superlattice showed a significant hysteresis. Nanoparticles can be assembled into superlattices and dimer clusters using a reconfigurable DNA device that also allows interparticle distances to be modified, post-assembly, in response to molecular stimuli.