Researchers have devised a way to make DNA bend and twist into a variety of new shapes, which may someday be used in nanoscale devices for delivering drugs inside the body, building tissues, or studying single proteins.
These findings, reported in the 7 August issue of Science, offer the nanotechnology field a way to construct objects with continuous curvatures.
For comparison, imagine if we could not make curving objects at the macroscale—we'd have no wheels, arches or hooks. Hendrik Dietz of Dana-Farber Cancer Institute and Harvard Medical School in Boston and of Technische Universität München in Munich, Germany, and colleagues now describe a way to make continuously curving nanoscale shapes.
Models of twisted and curved DNA-origami nanostructures. Each cylinder represents one DNA double helix. Curved segments are indicated in red. Twist and curvature are implemented with site-directed deletions and insertions of base pairs. [© Science/AAAS. Rendering in Autodesk Maya by Hendrik Dietz]
"Our goal was to find out whether we could program DNA to assemble into shapes that exhibit custom curvature or twist, with features just a few nanometers wide," Dietz said.
"It worked, and we can now build a diversity of three-dimensional nanoscale machine parts, such as round gears or curved tubes or capsules. Assembling those parts into bigger, more complex and functional devices should be possible."
The researchers designed bundles of DNA helices, arranged in a honeycomb lattice. Some of the helices had extra DNA base pairs inserted, while others had DNA deletions, which collectively created stresses that helped the bundles assemble into objects on the scale of tens of nanometers.
Using this method, the researchers could control the direction and degree of bending, even coaxing the molecules to bend at very tight angles. To demonstrate how their method could be used, the authors combined various curved elements to build more complex structures such as gears and beachball-shaped capsules.