Synthesis of stable 2D micro-assemblies of DNA tiles achieved via intrinsic curvatures in the skeleton of DNA duplexes coupled with the flexible support of the twisted side-arms

The science of DNA nanotechnology has led to the synthesis of size-controllable materials with uniformed geometries at nano- and micro-scales. Herein, we proposed the double-crossover (DX), antiparallel, and even half-turns perimeter tiles (DAE tiles) to synthesize intact, mono-crystalline, and giant 2D DNA micro-assemblies. The DNA tiles with 10-half-turns perimeter were synthesized via self-assembly of 106 nucleotides (NT) circular scaffold along with the complimentary staple strands. The DAE DNA tiles were successfully polymerized to achieve stable lattices by adjusting the inter-tile distances of certain lengths for attaining torsional (or twisting) chirality. We determined that the inter-tile connections affected the degree of coiling (or super-coiling) and twisting forces (right- or left-handed twists) in the DNA helix. While the degree of polymerization of DNA tiles was also tune-able by controlling the lengths and structural designs of the circular core of the DNA tiles. Furthermore, the number of half-turns in the core and on the connection arms (4 or 5) with even “E” or odd “O” half-turns was crucial. It affected the direction of winding of DNA duplexes to alter the overall stiffness and sturdiness of DNA lattices. The number of half-turns in the connections were either “4 or Even (21 NT); E with 5 NT sticky ends” or “5 Odd (26 NT); O with 6 NT sticky ends” (DAE-E or DAE-O tile systems). The AFM results revealed that the above tile systems (DAE-E or DAE-O) together with the locations of crossovers, and holiday junctions along the DNA tiles controlled the left- or right-handed coiling of DNA double strands. This phenomenon affected the compactness of resulting DNA motifs, the overall intrinsic curvatures, double-strand packing, and the geometry of DNA lattices.