A zwitterion-DNA coating stabilizes nanoparticles against Mg2+ driven aggregation enabling attachment to DNA nanoassemblies.

Plasmonics and photonics demand new methods for the controlled construction of nanoparticle (NP) arrays. Complex, low-symmetry configurations of DNA-functionalized NPs are obtained by connection to scaffolds of branched and folded DNA nanostructures. However, the stabilization of these branched structures by Mg(2+) counterions also drives the uncontrolled aggregation of NPs. We demonstrate, using a two-dimensional DNA scaffold, that derivatizing gold nanoparticles (AuNPs) with zwitterionic ligands overcomes this problem.