The Biodesign Institute Arizona State University

Figure 1 a and b display schematics for 2-D nanoforms with accompanying AFM images of the resulting structures. 1 c-e represent 3D structures of hemisphere, sphere and ellipsoid, respectively, while figure 1f shows a nanoflask, (each of the structures visualized with TEM imaging).

Earlier this week, we learned about wedding rings made out of DNA. Now, the ability to fold stringy bits of DNA into patterns and shapes has gone 3-D thanks to a new technique pioneered at Arizona State University's Biodesign Institute.

The breakthrough, reported in the April 15 issue of Science, is a step on the road to eventually using the procedure to create diminutive drug delivery devices, nano-computers, and chemical factories.

So-called DNA origami was introduced in 2006 by Paul Rothemund of the California Institute of Technology. It hinges on the self-assembling properties of DNA's four complimentary base pairs, which form the famous double helix.

These nucleotides, labeled A, T, C and G, follow a formula of how they interact. A always pairs with T and C with G. DNA origami practitioners exploit this base pairing to create complex shapes, but until now most shapes were two dimensional.

To do this, they frame the desired shape with a length of single-stranded DNA and then use DNA "staple strands" to cross over and integrate the structure and hold the desired shape.

"Our goal is to develop design principles that will allow researchers to model arbitrary 3-D shapes with control over the degree of surface curvature," Yan Liu of the Biodesign Institute, said in a news release explaining the research.

"In an escape from a rigid lattice model, our versatile strategy begins by defining the desired surface features of a target object with the scaffold, followed by manipulation of DNA conformation and shaping of crossover networks to achieve the design."

To achieve this, the team starts with simple, 2-D concentric ring structures formed from a DNA double helix and bound together at strategically placed crossover points. Varying the number of nucleotides between crossover points allows the designer to combine sharp and rounded elements into 2-D and 3-D forms.

More on tricks with DNA:

• 'Wedding Rings' made out of DNA
• Slideshow: Making smiley faces from DNA
• DNA robots pave way for microscopic factories 
• DNA twisted into pretzels
• Play a game and engineer real RNA