Directed Assembly of Discrete Gold Nanoparticle Groupings Using\nBranched DNA Scaffolds

The concept of self-assembled dendrimers is explored for the creation of discrete nanoparticle assemblies.\nHybridization of branched DNA trimers and nanoparticle−DNA conjugates results in the synthesis of\nnanoparticle trimer and tetramer complexes. Multiple tetramer architectures are investigated, utilizing\nAu−DNA conjugates with varying secondary structural motifs. Hybridization products are analyzed by\ngel electrophoresis, and discrete bands are observed corresponding to structures with increasing numbers\nof hybridization events. Samples extracted from each band are analyzed by transmission electron\nmicroscopy, and statistics compiled from micrographs are used to compare assembly characteristics for\neach architecture. Asymmetric structures are also produced in which both 5- and 10-nm Au particles are\nassembled on branched scaffolds.