Binary self-assembly of highly symmetric DNA nanocages via sticky-end engineering

Discrete and symmetric three-dimensional (3D) DNA nanocages have been revoked as excellent candidates for various applications, such as guest component encapsulation and organization (e.g. dye molecules, proteins, inorganic nanoparticles, etc.) to construct new materials and devices. To date, a large variety of DNA nanocages has been synthesized through assembling small individual DNA motifs into predesigned structures in a bottom-up fashion. Most of them rely on the assembly using multiple copies of single type of motifs and a few sophisticated nanostructures have been engineered by co-assembling multi-types of DNA tiles simultaneously. However, the availability of complex DNA nanocages is still limited. Herein, we demonstrate that highly symmetric DNA nanocages consisted of binary DNA point-star motifs can be easily assembled by deliberately engineering the sticky-end interaction between the component building blocks. As such, DNA nanocages with new geometries, including elongated tetrahedron (E-TET), rhombic dodecahedron (R-DOD), and rhombic triacontahedron (R-TRI) are successfully synthesized. Moreover, their design principle, assembly process, and structural features are revealed by polyacryalmide gel electrophoresis (PAGE), atomic force microscope (AFM) imaging, and cryogenic transmission electron microscope imaging (cryo-TEM) associated with single particle reconstruction.