DNA is a clever molecule that folds easily, so it can be used to act as scaffolds for nanomaterials. This involves long, single strands of DNA that have shorter strands to act as staples.
Folded DNA shocked many science enthusiasts in 2006, when California Institute of Technology’s Paul Rothermund released images of a smiley face made out of DNA. The smiley face was thousands of times smaller than the width of a human hair.
This technique has since been dubbed “DNA origami” because of how the DNA folds to make shapes and patterns.
Inspired by this, a team of researchers led by Lior Shani of Bar-Ilan University, Israel, described how to exploit DNA origami as a nanoscopic platform to build superconducting 3D architecture. Their paper is published in American Institute of Physics Advances.
The fabrication processes converted DNA origami nanostructures into superconducting components by coating them in conducting compounds.
“In our case, the structure is an approximately 220-nanometre-long and 15-nanometre-wide DNA origami wire,” says Shani. “We dropcast the DNA nanowires onto a substrate with a channel and coat them with superconducting niobium nitride.”
Superconductors are particularly useful because they lose very little energy as heat. One problem with doing this in the past was that small nanomaterials don’t behave like larger superconductors.
Unfortunately, some nanoscopic superconducting wires can experience what are called quantum fluctuations – that is, tiny, random energy changes. This can prevent normal superconducting and the wires appear to experience resistance.
To overcome this, Shani’s team used a high magnetic field that suppressed these fluctuations and eliminated about 90% of the resistance.
Together with the strict control of shape building that DNA origami provides, this can create tiny, tightly controlled 3D nanomaterials that still superconduct.
“This means that our work can be used in applications like interconnects for nanoelectronics, and novel devices based on exploitation of the flexibility of DNA origami in fabrication of 3D superconducting architectures, such as 3D magnetometers,” says Shani.
Dr Deborah Devis is a science journalist at The Royal Institution of Australia.
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