Dynamic DNA Origami-Based Nanoparticle Assemblies

Abstract

We used the DNA origami method [1] for the fabrication of functional self-assembled nanoscopic objects and materials [2]. In DNA origami, a virus-based 8 kilobase-long DNA single-strand is folded into shape with the help of ∼ 200 synthetic oligonucleotides and the resulting DNA nanostructures can be designed to adopt any three-dimensional shape. By harvesting the potential to offer attachment sites with nanometer precision on these objects, we have realized complex assemblies of nano-components, including organic fluorophores as well as magnetic, fluorescent and plasmonic nanoparticles. Our nanoconstructs can exhibit striking optical properties such as strong optical activity in the visible range [3] and they can be tethered to surfaces and be operated by external stimuli. Currently, several methods to manipulate DNA nanoconstructs are investigated in our laboratory. For example, by switching the orientation of nanoparticle helices we were able to dynamically control the optical activity of the composite material. The observed circular dichroism signals are reversible and can be explained qualitatively and quantitatively with plasmonic dipol theory. In recent experiments, we were able to show that the optical response of chiral biomolecules can be transferred from the UV into the visible region in non-chiral plasmonic hotspots. Thus, sensitive detection of chiral bio-molecules may become feasible with this approach.[1] Rothemund, P.W.K. Folding DNA to create nanoscale shapes and patterns. Nature 440, p207, 2006.[2] Seeman, N.C. Nanomaterials based on DNA. Annu. Rev. Biochem. 79, p12.1, 2010.[3] Kuzyk, A. et al. DNA-based self-assembly of chiral plasmonic nanostructures with tailored optical response. Nature 483, p311, 2012.