DNA dumbbell tiles with uneven widths for 2D arrays.

Small DNA tiles built from linear oligonucleotides for the construction of DNA nanostructures often have even widths in the lateral direction against the DNA helical axis. Herein we present an example of DNA dumbbell tiles with uneven widths between the central double helical stem and the two head loops after association with helper strands. A characteristic of DNA dumbbell tiles is that the stem length controls the stereostructure of the two head motifs. A stem at 11 bp twists two head motifs of a dumbbell tile into parallel conformations, wheareas a stem at 16 bp twists two head motifs into antiparallel conformations. We successfully constructed four DNA dumbbell tiles and assembled them into two-dimensional (2D) arrays of planar nanoribbons with zebra-like patterns and fine nanotubes as well.