Resolution of a tricky biochemical challenge has helped University of Sydney scientists develop a new DNA-based technique that could revolutionise healthcare and other industries by enabling the creation of nanoscale robots and tools for applications like drug delivery.

The new ‘velcro’ DNA, which was developed by University of Sydney Nano Institute researchers Dr Minh Tri Luu and Dr Shelley Wickham, uses DNA’s natural folding power to create precisely engineered nanostructures a fraction of the width of a human hair.

Each ‘building block’ of DNA – the fundamental biological structure whose sequence of molecules determines how cells are made – is designed so that it only bonds to other blocks with specifically designed, complementary receptors.

This allows the DNA to be joined together into any sort of shape or structure, providing a way to build new structures out of DNA.

"You can have a pool of building blocks that just sit there in solution,” Wickham told Information Age, “and they just sit there and aren’t going to do anything – but when you add some of these glue DNA strands, it will form different shapes.”

The team, whose work was recently published in the journal Science Robotics, has already developed over 50 different nanoscale objects including a dancing robot, ‘nano dinosaur’, and a map of Australia just 150 nanometres across, or 1/1000th the width of a human hair.

Just three building blocks can be stitched together in 17 different ways, and the team’s experiments showed that all 17 could be created and assembled into durable components that could in turn be used to build nanoscale robotic arms, 360-degree gears, and more.

“Once you move up to 12 building blocks there’s such a huge diversity of shapes,” Wickham said, with compact shapes proving to be stronger than flexible ones.

Indeed, the flexibility of DNA proved to be a stubborn challenge for the researchers, who found that early versions of the building blocks “were kind of twisted” because of DNA’s inherent helix shape.

“If you’re building a house, your building blocks need to be perfectly square to stack properly,” Wickham explained.

“DNA’s helicity isn’t that precisely known so it took us ages to get rid of the twist – but once we did, everything we tried after that worked really great.”

Project began as ‘complete accident’

The results have the team contemplating Fantastic Voyage-esque nanostructures that could benefit fields including synthetic biology, nanomedicine, and materials science.

It is a significant outcome for a project that Wickham said started as a “complete accident” back in 2006.

Her intended PhD research project required the use of lasers that were broken at the time, she recalled, but after a redirection by her supervisor she never looked back.

“One of the things I like about working with DNA is that it’s this cross between biology and engineering and material science and physics,” she said, “but it’s also very reproducible – so the field moves very quickly.

“As soon as you publish something, everyone else can buy the same DNA and do the same experiments with it – and because of that, the field is very interactive and moves very fast.”

Dr Shelley Wickham (left) says her team will continue to find ways to use DNA to build new nanostructures. Photo: Stefanie Zingsheim / University of Sydney

There’s gold in the minutiae

The success of the University of Sydney team reflects ongoing work to refine nanotechnology techniques that manipulate materials at the molecular level – and even quantum engineering projects that work at the level of individual electrons.

The ability to control materials at such low levels offers the tantalising promise of developing new materials that are designed specifically to transfer heat, improve battery design, create strong microstructures, and target cancer treatments and other medications to specific cells.

Australian researchers’ nanotechnology success has been globally recognised, with one index seeing Australia post an “unusually large” climb to 8th place – and the only country apart from China to have more than one top-ranked nanotech institution.

Aiming to build on that momentum and capitalise on growing government support for the sector, Melbourne’s RMIT University last month opened a Centre for Atomaterials and Nanomanufacturing (CAN) that will innovate alongside industry bodies like Innofocus.

CAN researchers have already developed nanotechnology prototypes including a radiative cooling film that blocks the absorption of heat, graphene supercapacitors for energy storage, and a solar to hydrogen generator that generates hydrogen fuel and purifies wastewater.

“Atomaterials present a once-in-a-generation opportunity for Australian innovation,” distinguished professor Baohua Jia said as the CAN was announced amidst undertakings to “work directly with industry partners to drive applied research in critical sectors.”

Meanwhile, Wickham’s team will continue exploring the opportunities to use DNA to build new types of nanostructures – noting that DNA “is a bit of a sweet spot for complexity and simplicity… we show in our paper that you can really make any type of shape”.