i. Cylinder model of the DNA nanostructures, with each cylinder representing a DNA double helix. (a), Six-helix bundle, (b), Twelve-helix bundle. (c), Six-helix bundle ring. (d), Prestressed tensegrity-structure kite. ii, kb ladder. iii, Unpurified DNA nanostructures, arrows indicate the region of each lane that was extracted from the gel during purification before TEM imaging. iv, 30% sucrose-gel-purified nanostructures. v, Pellet-pestle homogenization recovered gel-purified nanostructures. ImageJ was used for gel-image analysis to estimate the yield of purification (bottom of each lane). vi, TEM micrographs of the nanostructures after 30% sucrose gel purification. Lane images for each object cropped from a single gel.