Programming the self-assembly of DNA-origami colloids into nanotubes

DNA origami is a method by which a single-stranded DNA scaffold is folded into some prescribed shape by hundreds of user-designed DNA ‘staple’ strands. Historically, this process has been used to make intricate 3D nanostructures with sub-nanometer precision. In this talk, I will discuss a new route for using DNA origami to make colloidal particles that then self-assemble into well-defined geometrical structures. More specifically, we use DNA origami to make triangular subunits and control their binding angles to program the assembly of nanotubes. The nanotubes are assembled from one type of triangle whose three edges bind to themselves at prescribed dihedral angles and are programmed by the DNA sequence design. We show that DNA origami triangles, which are each roughly 50 nanometers in size, can assemble into rigid tubules reaching a few micrometers in length. This scale corresponds to roughly 10 giga-Daltons—one of the largest assemblies made from DNA origami. Interestingly, we find that there is a distribution in the width and the chirality of the assembled tubes, suggesting that our DNA origami colloids could be flexible or that the kinetic pathway toward tube closure plays an important role in determining the final structure.