Binding assistance triggering attachments of hairpin DNA onto gold nanoparticles

Here, we present a strategy to trigger monovalent attachments of thoilated hairpin DNA onto AuNP, assisted by molecular binding. Without binding helper strands, it is hard to control the attachments of thiolated hairpin DNA, because of spatial hindrances. By introducing a binding helper strand, the thiol-group can be brought into close proximity to the surface of AuNPs, which will greatly increase the local molecular concentration and attaching efficiency. In the experiments, the strategy is verified by the methods of DNA strand branch migration and dynamic assembly of AuNPs clusters. In addition, unique and complex AuNPs clusters with well-defined arrangements of DNA scaffolds are produced. Using this method, it is able to selectively manipulate and control different kinds and numbers of DNA attaching onto AuNPs. Our strategy also could be extended to assembling large complicated DNA/AuNPs programmable structures and nanodevices.