A new building block for structural DNA nanotechnology uses a 3-carbon glycerol molecule instead of the 5-carbon sugar deoxyribose found in DNA. To begin exploring this new DNA nanotech, the researchers made a simple four-helix junction of the type pioneered in Ned Seeman’s laboratory, and found that nanostructures built from GNA not only tolerate higher temperatures than do comparable structures made with DNA, but both left-handed and right-handed four-helix junctions are obtained—something not easily done with DNA. An excerpt from “Scientists make chemical cousin of DNA for use as new nanotechnology building block” from Arizona State University, via AAAS EurekAlert:

In the Biodesign Institute at Arizona State University, researchers are using DNA to make intricate nano-sized objects. Working at this scale holds great potential for advancing medical and electronic applications. DNA, often thought of as the molecule of life, is an ideal building block for nanotechnology because they self-assemble, snapping together into shapes based on natural chemical rules of attraction. This is a major advantage for Biodesign researchers like Hao Yan, who rely on the unique chemical and physical properties of DNA to make their complex nanostructures.

While scientists are fully exploring the promise of DNA nanotechnology, Biodesign Institute colleague John Chaput is working to give researchers brand new materials to aid their designs. In an article recently published in the Journal of the American Chemical Society [abstract], Chaput and his research team have made the first self-assembled nanostructures composed entirely of glycerol nucleic acid (GNA)—a synthetic analog of DNA.

…”Making GNA is not tricky, it’s just three steps, and with three carbon atoms, only one stereo center,” said Chaput. “It allows us to make these right and left-handed biomolecules. People have actually made left-handed DNA, but it is a synthetic nightmare. To use it for DNA nanotechnology could never work. It’s too high of a cost to make, so one could never get enough material.”

The ability to make mirror image structures opens up new possibilities for making nanostructures. The research team also found a number of physical and chemical properties that were unique to GNA, including having a higher tolerance to heat than DNA nanostructures. Now, with a new material in hand, which Chaput dubs ‘unnatural nucleic acid nanostructures,’ the group hopes to explore the limits on the topology and types of structure they can make.

It will be particularly interesting to see what kind of use this new structural GNA nanotechnology makes of the ease of making left- and right-handed helices.
—Jim

The nanotechnology of engineering atomic layer interfaces to produce desired properties—in this case, something called ‘improper ferroelectricity’—promises a technological revolution that may be comparable to the development of modern electronics. From a Stony Brook University news release via ScienceDaily:

In the 10 April issue of Nature [abstract], a new artificial material is revealed that marks the beginning of a revolution in the development of materials for electronic applications…

The new material, a superlattice, which has a multilayer structure composed of alternating atomically thin layers of two different oxides (PbTiO3 and SrTiO3), possesses properties radically different to either of the two materials by themselves. These new properties are a direct consequence of the artificially layered structure and are driven by interactions at the atomic scale at the interfaces between the layers.

“Besides the immediate applications that could be generated by this nanomaterial, this discovery opens a completely new field of investigation and the possibility of new functional materials based on a new concept: interface engineering on the atomic scale,” said [one of the lead researchers Dr. Matthew] Dawber.

Transition metal oxides are a class of materials that provoke great interest because of the great diversity of properties which they can present (they can be dielectrics, ferroelectrics, piezoelectrics, magnets or superconductors) and their ability to be integrated into numerous devices. The majority of these oxides possess a similar structure (referred to as ‘perovskite’) and, recently, researchers have developed the ability to build these kinds of materials up, atomic layer by atomic layer, much as a child plays with Lego bricks, hoping to produce new materials with exceptional properties.

—Jim