Compositions and methods for fractal assembly of micron-scale nucleic acid structures

A nucleic acid microstructure comprising:

• an n×n array of n2 polynucleotide square tiles, each of the n2 polynucleotide square tiles comprising:
• a single-stranded helical polynucleotide scaffold of a known sequence;
• and
• a plurality of selected single-stranded polynucleotide staple strands being at least partially complementary to the polynucleotide scaffold and annealed to the polynucleotide scaffold to form a square tile shape;
• the n×n array of n2 polynucleotide square tiles further comprising a plurality of 2×2 sub-arrays, each of the plurality of 2×2 sub-arrays comprising a set of four polynucleotide square tiles, each of the four polynucleotide square tiles having p number of inside single-tile extended polynucleotide staple strands or p number of inside single-tile truncated polynucleotide staple strands, the inside single tile extended polynucleotide staple strands being annealed with the inside single-tile truncated polynucleotide staple strands to form the plurality of 2×2 sub-arrays, wherein each of the plurality of 2×2 subarrays comprise four two-tile edges and any inside two-tile edges in any of the plurality of 2×2 sub-arrays have less than p number of inside two-tile extended polynucleotide staple strands or less than p number of inside two-tile truncated polynucleotide staple strands, where the inside two-tile extended polynucleotide staple strands are annealed with the inside two-tile truncated polynucleotide staple strands to form at least one 4×4 subarray.