Geometry guided crystallization of anisotropic DNA origami shapes.

Three-dimensional assembly based on DNA origami structures is an ideal method to precisely fabricate nano-scale materials. Additionally, applying an anisotropic assembly unit facilitates constructing complex materials with extraordinary structure. However, it still remains challenging to crystallize anisotropic DNA nano-structures using simple design, because the assembly of low-symmetry monomers often requires harsh auxiliary conditions and more complicated crystallization processes. In this work, we managed to crystallize the anisotropic elongated octahedral DNA origami frames by non-specific connections, and acquired two kinds of highly ordered superlattices purely by conducting multiple annealing processes and increasing the rigidity of the connection parts. In the case where the connection parts were composed of soft DNA sticky ends, we obtained the theoretically inaccessible simple cubic superlattices by this anisotropic DNA origami shape. Through characterization by small-angle X-ray scattering and scanning electron microscopy, we found that the DNA monomers are arbitrarily arranged due to the stress buffering of the soft DNA SEs, while in the stiffer case, simple tetragonal superlattices with translational arrangement of most anisotropic DNA origami shapes were synthesized as expected. This work deepened the understanding of geometry-guided crystallization of DNA origami shapes and provided a new path for constructing three-dimensional functional devices with simple design.