DNA isn't just a building block of life -- it can be a building block for other nano-size structures too. These wonderfully intricate shapes are made by twisting and folding DNA into complex shapes using a newly developed technique, like a kind of advanced molecular DNA.
Here, DNA isn't being used to carry genetic information; rather, it's a structural material in its own right. Its four bases -- adenine, cytosine, guanine and thymine -- bind more or less strongly to one another depending on how they're paired up along the length of a DNA double helix, allowing scientists to tweak the way in which they join together.
The shapes have been made by a team of researchers from Arizona State University's Biodesign Institute. They represent a leap forward in terms of control and precision when it comes to folding DNA molecules into useful new shapes. "Earlier design methods used strategies including parallel arrangement of DNA helices to approximate arbitrary shapes," explains Hao Yan, who led the research, to Science Direct, "but precise fine-tuning of DNA wireframe architectures that connect vertices in 3D space has required a new approach."
In the past, the structures created using DNA origami have been regular and very symmetrical, but the new technique -- explained Nature Nanotechonology -- allows researchers to create more complex and arbitrary shapes. That's made possible by a new means of weaving together the DNA strands at each vertex, allowing the angle of each branch to be tweaked and as many as 10 of the strands to be woven together.
The resulting shapes include intricate 2D planar patterns and even a kind of art sketch, all shown above. But the technique also allows for the production of 3D objects, including the so-called Archimedean solid cuboctahedron shown just above, with its 12 vertices and 24 edges. Interestingly, it can be made in such a way that it can be unfolded and lain down flat -- like the nets you used to make at grade school.
The researchers claim that the new technique could be used to build up any kind of wireframe nanostructure, as long as no vertex requires more than 10 strands to join at any point. And it's not just a question of origami for art's sake: these kinds of structures will give rise to a new kind of nanotechnology, where the DNA structures form molecular assembly lines to make increasingly large objects.