Fig. 1.

The design of a DNA tile system for the formation of a variety of tubular structures carrying 5-nm AuNPs. (A and B) Top and side view of the four DX tiles (A tile, blue; B tile, red; C tile, green; and D tile, brown). The A tile carries a 5-nm AuNP on the top of the tile. The C tile carries a DNA stem loop pointing downward. (C) The four different tiles are designed to self-assemble into a 2D array displaying parallel lines of AuNPs. (D) Possible ways for the corresponding edge tiles on opposite sides of the 2D array to associate and lead to formation of tubes displaying patterns of AuNPs in stacked rings, single spirals, double spirals, and nested spiral tubes. (E) The different tube conformations were observed in a single TEM image.