摘要：SummaryTwo-dimensional (2D) DNA origami that is capable of self-assembling into complex 2D and 3D geometries pave the way for a bottom-up synthesis for various applications in nano/biotechnology. Here, we directly visualized the aqueous structure of 2D DNA origami cross-tiles and their assemblies using cryogenic electron microscopy. We uncovered flexible arms in cross-tile monomers and designated inter-tile folding. In addition, we observed the formation of clusters and stacks of DNA cross-tiles in solution, which could potentially affect the interaction and assembly of DNA origami. Finally, we quantitatively evaluated the flexibility of DNA origami in solution using finite element analysis. Our discovery has laid the foundation for investigating the dynamic structures of 2D DNA origami assemblies in solution, providing insights regarding the self-assembly and self-replication mechanisms of 2D DNA origami.Graphical abstractDisplay OmittedHighlights•2D DNA origami is floppy in solution•Cryo-EM pictures unstained monolayer DNA origami with details•2D DNA origami cross-tiles have flexible arms and form clusters and stacks•Dimmer and trimmer complexes can fold in solution on designMaterials science; Materials chemistry; Biomaterials; Materials characterization
