The design of self-assembled 3D DNA networks

Structural DNA Nanotechnology uses unusual DNA motifs to build target shapes and arrangements. These unusual motifs are generated by reciprocal exchange of DNA backbones, leading to branched systems with many strands and multiple helical domains. The motifs may be combined by sticky ended cohesion, involving hydrogen bonding or covalent interactions. Other forms of cohesion involve edge-sharing or paranemic interactions of double helices. A large number of individual species have been developed by this approach, including polyhedral catenanes, such as a cube and a truncated octahedron, a variety of single-stranded knots, and Borromean rings. In addition to these static species, DNA-based nanomechanical devices have been produced that are targeted ultimately to lead to nanorobotics. Many of the key goals of structural DNA nanotechnology entail the use of periodic arrays. A variety of 2D DNA arrays have been produced witii tunable features, such as patterns and cavities. A central goal is the extension of this system from 2D to 3D. Designs and diffraction results of some preliminary 3D arrays are described. It is possible to design motifs that self-assemble to yield material that diffracts x-rays.