Biological materials are self-assembled with near-atomic precision in living cells, whereas synthetic 3D structures generally lack such precision and controllability. Recently, DNA nanotechnology, especially DNA origami technology, has been useful in the bottom-up fabrication of well-defined nanostructures ranging from tens of nanometres to sub-micrometres. In this Primer, we summarize the methodologies of DNA origami technology, including origami design, synthesis, functionalization and characterization. We highlight applications of origami structures in nanofabrication, nanophotonics and nanoelectronics, catalysis, computation, molecular machines, bioimaging, drug delivery and biophysics. We identify challenges for the field, including size limits, stability issues and the scale of production, and discuss their possible solutions. We further provide an outlook on next-generation DNA origami techniques that will allow in vivo synthesis and multiscale manufacturing.

DNA tile based self-assembly provides an attractive route to create nanoarchitectures of programmable patterns. It also offers excellent scaffolds for directed self-assembly of nanometer-scale materials, ranging from nanoparticles to proteins, with potential applications in constructing nanoelectronic/nanophotonic devices and protein/ligand nanoarrays. This Review first summarizes the currently available DNA tile toolboxes and further emphasizes recent developments toward self-assembling DNA nanostructures with increasing complexity. Exciting progress using DNA tiles for directed self-assembly of other nanometer scale components is also discussed.

Artificial lipid-bilayer membranes are valuable tools for the study of membrane structure and dynamics. For applications such as studying vesicular transport and drug delivery, there is a pressing need for artificial vesicles with controlled size. However, controlling vesicle size and shape with nanometer precision is challenging and approaches to achieve this can be heavily affected by lipid composition. Here we present a bio-inspired templating method to generate highly monodispersed sub-100nm unilamellar vesicles, where liposome self-assembly was nucleated and confined inside rigid DNA nanotemplates. Using this method we produced homogenous liposomes with four distinct pre-defined sizes. We also show that the method can be used with a variety of lipid compositions and probed the mechanism of the templated liposome formation by capturing key intermediates during membrane self-assembly. The DNA nanotemplating strategy represents a conceptually novel way to guide the lipid bilayer formation, and could be generalized to engineer complex membrane/protein structures with nanoscale precision.

Designer nanoparticles with controlled shapes and sizes are increasingly popular vehicles for therapeutic delivery due to their enhanced cell-delivery performance. However, our ability to fashion nanoparticles has offered only limited control over these parameters. Structural DNA nanotechnology has an unparalleled ability to self-assemble three-dimensional nanostructures with near-atomic resolution features, and thus, it offers an attractive platform for the systematic exploration of the parameter space relevant to nanoparticle uptake by living cells. In this study, we examined the cell uptake of a panel of 11 distinct DNA-origami shapes, with the largest dimension ranging from 50-400 nm, in 3 different cell lines. We found that larger particles with a greater compactness were preferentially internalized compared with elongated, high-aspect-ratio particles. Uptake kinetics were also found to be more cell-type-dependent than shape-dependent, with specialized endocytosing dendritic cells failing to saturate over 12 h of study. The knowledge gained in the current study furthers our understanding of how particle shape affects cellular uptake and heralds the development of DNA nanotechnologies toward the improvement of current state-of-the-art cell-delivery vehicles.