408 9.3  Synthetic Biology, Biomimicry, and Bionanotechnology

FIGURE 9.3  DNA origami. (a) Three or four strands of DNA can be designed to have comple­

mentary segments as indicated, giving rise to self-​assembled 2D arrays with either hexagonal

or square lattices, respectively. (b) Using more complex design involving more complemen­

tary DNA segments, 3D DNA nanostructures can be generated, such as tetrahedrons and

cubes shown here (though more generally nontrivial geometrical shapes objects can also be

generated). The original DNA tetrahedron design was conceived using six toilet roll tubes, some

paper, and some colored bits of bendy wire (right panel: Courtesy of Richard Berry, University

of Oxford, Oxford, UK). (c) Artificial DNA molecular motors all use toehold-​mediated strand dis­

placement, for example, strands A and B here are complementary, and so the addition of strand

B to the solution will displace strand C from the A–​C DNA nanostructure indicated.