A Fresh Look at DNA Nanotechnology

Synthetic DNA structures for nanotechnological applications have experienced substantial success during the past decades benefiting from Seeman and his coworkers' pioneering work. In the last few years, some new branches have been emerging in this field. This review will summarize some recent progress in the authors' group. Forming crystalline DNA lattices in one, two and even three dimensions has long been a hot topic of DNA nanotechnology. These artificially designed lattices are the basis for a variety of applications. The first success with a 2D DNA lattice was achieved in [22] with building blocks of double-crossover (DX) DNA molecules. Following that, rhombus motifs, triple-crossover molecules, and a cross motif were also constructed from branched four-arm Holliday junctions [19]. Here we present a tensegrity strategy for the construction of well-structured DNA triangle molecules [14]. A DNA triangle consists of three vertices (DNA four-arm junctions) and three sides (DNA duplexes). Although individual four-arm junctions are flexible, the rigidity of the three duplex edges restricts the freedom of the component four-arm junctions and only triangles can form. The shape of such a triangle is fully defined by the lengths of the three edges. By rational use of sticky-end cohesion, we have successfully assembled triangle arrays in one and two dimensions. Fig. 1 shows the design of some such triangle arrays and some atomic force microscope (AFM) images of such triangle arrays.