Figure 10.

The DNA origami template for the hierarchical Robinson tiles. The DNA origami cross is about 100 nm across and has 12 DNA helices at each edge, grouped in 6 pairs, each ending in a variable number of base pairs whose sequence is independent of the origami template strand sequence. Origami template DNA is shown in iron gray, independent sequences are red, and staple strands are shown in other colors. Staple strands can be extended to provide the functional DNA strands of each tile. Additionally, some helices are lengthened and others shortened to provide shape complementarity to the arrow heads and arrow tails edges, and to provide steric hindrance the to binding between two edges containing arrow heads. These DNA tiles without the edge modifications have been shown to assemble into high quality two-dimensional arrays (Liu et al., 2011). This image was generated using Nanoengineer-1 (Nanorex Inc., 2008) and Pymol (Schrödinger, LLC, 2010).