|Nadrian C. Seeman
Department of Chemistry, New York University, New York, NY 10003, U.S.A.
DNA nanotechnology uses reciprocal exchange between DNA double helices or hairpins to produce branched DNA motifs or related structures, such as double crossover (DX), triple crossover (TX), paranemic crossover (PX) and parallelogram motifs. We combine DNA motifs to produce specific structures by using sticky-ended cohesion, or, more recently, a form of paranemic cohesion. From simple branched junctions, we have constructed DNA stick-polyhedra, knots and Borromean rings. We have used two DX molecules to construct a DNA nanomechanical device by linking them with a segment that can be switched between left-handed Z-DNA with right-handed B-DNA. PX DNA has been used to produce a robust sequence-dependent device; sequence-dependent devices can provide the diversity of structures necessary for nanorobotics.
A central goal of DNA nanotechnology is the self-assembly of periodic matter. We have constructed micron-sized 2-dimensional DNA arrays from DX, TX and parallelogram motifs. We can produce specific designed patterns visible in the AFM from DX and TX molecules. We can change the patterns by changing the components, and by modification after assembly. In addition, we have generated 2D arrays from DNA parallelograms. These arrays contain cavities whose sizes can be tuned by design. In addition to specific periodic self-assembly, we have performed algorithmic constructions, corresponding to XOR operations.
This research has been supported by grants from the NIGMS, ONR, DARPA, NSF and USAF.