Researchers at Aarhus University have used cryo-EM to gain a better understanding of the folding process that dictates RNA origami. Among other things, they found a kinetic phase from which an RNA structure could only free itself after ten hours, they write in Nature Nanotechnology.

RNA is an excellent building block for creating diverse, well-defined structures at the nanoscale. The power of RNA origami lies precisely in the fact that the RNA strands eventually achieve the desired three-dimensional shape through self-assembly and programmed folding. For example, a neat little bundle of interconnected helices that together form a larger hollow cylinder in which a cargo can be transported. Or, conversely, a flat stack of helices that acts as a kind of ’wall’ that can be used to build ’scaffolds’ for applications in synthetic biology.