This work demonstrates the use of a circuit-like DNA origami structure as a template to fabricate conductive gold and copper nanostructures on Si surfaces. We improved over previous results by using multiple Pd seeding steps to increase seed uniformity and density. Our process has also been characterized through atomic force microscopy, particle size distribution analysis, and scanning electron microscopy. We found that four successive Pd seeding steps yielded the best results for electroless metal plating on DNA origami. Electrical resistance measurements were done on both Au- and Cu-metallized nanostructures, with each showing ohmic behavior. Gold-plated DNA origami structures made under optimal conditions had an average resistivity of 7.0 × 10(-5) Ω·m, whereas copper-metallized structures had a resistivity as low as 3.6 × 10(-4) Ω·m. Importantly, this is the first demonstration of electrically conductive Cu nanostructures fabricated on either DNA or DNA origami templates. Although resistivities for both gold and copper samples were larger than those of the bulk metal, these metal nanostructures have the potential for use in electrically connecting small structures. In addition, these metallized objects might find use in surface-enhanced Raman scattering experiments.

This work examines the selective deposition of two different metals on a single DNA origami template that was designed and assembled to direct the deposition. As a result, we were able to direct copper and gold to predesignated locations on the template, as verified by both compositional and morphological data, to form a heterogeneous Cu-Au junction. Seeding and deposition were performed in sequential steps. An enabling aspect of this work was the use of an organic layer or "chemical mask" to prevent unwanted deposition during the deposition of the second metal. In light of recent efforts in the field, the ability to localize components of different composition and structure to specific sections of a DNA template represents an important step forward in the fabrication of nanostructures based on DNA templates.

The field of structural DNA nanotechnology has undergone significant expansion in recent years as exciting new techniques and understanding have been developed, allowing for the design and assembly of complex and intricate two- and three-dimensional nanostructures. Many of these designed DNA motifs have found use in precise positioning of nanomaterials and thereby can aid in studies, reactions, and assembly of other nanostructures. This review discusses the history and progression of DNA-based nanofabrication with an emphasis on the use of DNA nanostructures for electronics applications.

DNA origami is a valuable technique in arranging nanoparticles into various geometries with a $100 nm footprint, high resolution, and experimental simplicity. Aligned nanoparticles, in addition to being used for photonics, can also be utilized to create thin metal wires with intricate and asymmetric junctions.Many factors affect the yield and density of nanoparticles attached to DNA origami structures, including the length and number of attachment sequences, the reaction ratio of nanoparticles to DNA origami, the hybridization temperature, and age of the solutions. This work investigates the alignment of closely packed 5 nm gold nanoparticles along thin DNA origami structures. Several reaction conditions, including hybridization time, magnesium ion concentration, ratio of nanoparticles to DNA origami, and age of the nanoparticle solution, were explored to optimize nanoparticle attachment density and spacing. Optimum ranges of conditions were identified, yielding new insights into high-density nanoparticle attachment to thin DNA origami structures, with potential for application in nanowire and nanoelectronics construction.