DNA origami is an attractive technique for nanoscale design because of its simple and consistent design principles, from which it can produce self-assembling, spatially organized nanomaterials to study nanoscale phenomena.
Using thread-like DNA molecules, scientists at Duke University and Arizona State University have created tiny round objects: tiny vases, bowls and hollow spheres, one hidden inside the other, like household items for a Russian nesting doll. These objects can be bent and folded with nanometer precision into complex three-dimensional objects.
These creations demonstrate the capabilities of a new open-source software program. The software allows users to create drawings or digital models of rounded shapes and convert them into 3D structures made from DNA.
Any small hollow object is no more than two millionths of an inch wide. More than 50,000 can fit on the tip of a pin.
Scientists noted, “These are more than just nano-sculptures. The software allows us to create small containers to deliver drugs or molds for molding metal nanoparticles with specific shapes for solar cells, medical imaging and other applications.”
In addition to being a genetic information carrier, DNA is also the source code and building material.
The genetic code of DNA consists of four ‘letters’ or bases, which link together in our cells in a predictable way to form the rungs of the DNA ladder. The scientists have appropriated DNA’s rigorous base-pairing requirements (A to T and C to G). They can “program” DNA strands to join themselves into different shapes by creating DNA strands of certain shapes.
However, building structures with curved surfaces similar to those found in nature has been challenging. The team’s goal is to increase the variety of shapes that can be made using this technique.
To do that, scientists developed software called DNAxiS, which facilitates the design of curved, embedded DNA origami nanostructures with axially symmetrical geometry. It works similarly to how clay coils make pots by coiling a long DNA double helix into concentric rings that stack on top of each other to form the shape of the object. The scientists also made it possible to reinforce the structures with additional layers for greater stability.
John H. Reif – A. Hollis Edens Distinguished Professor of Computer Science, Duke University – said: “Practical applications of their DNA design software in the laboratory or clinic may still be years away. But it is a big step forward in the automated design of new three-dimensional structures.”
- Daniel Fu, Raghu Pradeep Narayanan et al. Automated design of 3D DNA origami with non-rasterized 2D curvature. Scientific Advances, 23 Dec 2022. DOI: 10.1126/sciadv.ade4455