The tremendously hardy and very old grass relies on its own nanotechnology to survive – but it may be able to lend us a hand too.
Somewhere between ten and twenty million years ago, the vast continent we now call Australia began to parch, as it drifted upwards towards the equator.
That slow progress, eked out over millions of taxing years, thrust species into a pulsing chaos: millennia of refuge followed by millennia of dusty crisis. The surviving species were those that adapted best to the slow desiccation of the continent.
“That’s why we have some of the highest biodiversity in the world,” explains Professor Susanne Schmidt, a plant biologist at the University of Queensland (UQ). “Other parts of the world had glaciation and things died out en masse, whereas here, we had this sort of phenomenal, slow evolution.”
Among the most successful of those new-born species, crafted through trial and fire, were the Australian spinifex grasses, genus Triodia, which now dominate about a third of the continent. You’ll recognise them as the spiky grasses that form gentle hummocks, little pockmarks of green on the burnished skin of the desert.
“This is a pretty unusual grass,” says Professor Darren Martin, a researcher in the School of Chemical Engineering at UQ. “It’s a survivor. It can handle 40 or 50 degrees in the middle of summer, and it still manages to stand up proud.”
Martin is not a biologist, he’s a materials engineer. In 2007, he received a phone call from Professor Paul Memmott, an anthropologist and architect at UQ .
Memmott had been in talks with Colin Saltmere about investigating the material properties of a Triodia grass, T. pungens, which grows on Saltmere’s traditional lands around the upper Georgina River in Far North Queensland.
Saltmere is an adjunct associate professor at the UQ School of Architecture, an Indjalandji-Dhidhanu elder with an epic roll call of hats, including CEO of Bulugudu, a corporation owned by the Indjalandji-Dhidhanu people.
“I make traditional stone tools, and I use a spinifex resin,” Saltmere tells me over the phone from his home in the outback Queensland town of Camooweal, an outback hamlet with a couple of hundred people, which is flush with the Northern Territory border. Saltmere uses the resin to haft stone to wood, as his ancestors have for thousands of years.
“It’s a fire grass, and it’s drought resistant, and it survives in places where other grasses won’t,” says Saltmere. “It’s a tough, tough grass.”
Saltmere began working with Memmott on writing an ARC Discovery Grant to conduct a scientific investigation into the possible uses of the grass, based on thousands of years of cultural practice. And, as Martin tells me, they needed a materials guy – which is why Memmott called him up.
The initial thrust of the research was looking at the sticky resins that Saltmere describes, and that arm of the project is still ongoing. But it was a PhD student Dr Nasim Amiralian, working closely with Martin on the project, who discovered that the plant had unusual nanocellulose fibres lining its cell walls.
Nanocellulose fibres exist in all plant matter, and can be derived and then used for a variety of purposes. They’re super strong, comparable to Kevlar, which makes them useful as a barrier for stretchy latex products like gloves and condoms, and they’re hydrophilic and viscous, so they can be used to make gels.
Nanocellulose is also biodegradable, so it’s an environmentally friendly alternative to traditional composite materials. Thousands of these products are being developed globally, from all sorts of different plants. But the nanocellulose obtained from Triodia pungens is different.
Firstly, T. pungens is so unique because its nanocellulose fibres have the highest aspect ratio of any known nanocellulose: they’re extraordinarily long and thin. Secondly, if you suspend those fibres in water, when they touch they will self-assemble into a matrix that stabilises the water in which they’re suspended, forming a gel. Thirdly, T. pungens, is incredibly easy to break down, making the process inexpensive and resource-conservative.
“My hypothesis at the time was that because this grass grows in specific very hot and dry environmental conditions in the Australian desert, it probably has a strategy to survive,” says Amiralian. That hypothesis seems to have been borne out.
“It adopted this strategy to survive the environment: it has a high content of hemicellulose which helps to retain the moisture and ease of fibrillation, as well as these hyperlinks.”
“There’s a link between traditional knowledge, where this grass is a sacred symbol of resilience, and we connected the western science with that,” says Martin.
“We discovered that spinifex was very, very easy to break down into a pulp using less water, less chemicals, and less energy, and we discovered that those same survival traits lead to a very different plant cell wall structure which led to a really amenable feedstock for making nanocellulose fibres.”
More than a decade after he initially jumped on board with the project, Martin visited an old friend, the late Dr Ian Griffiths who, at the time, was CEO of the Australian National Fabrication Facility (ANFF). The pair sat down at the aptly named Café Nano, at the Australian Institute for Bioengineering and Nanotechnology, at UQ’s campus in St Lucia.
“Ian was one of those amazing people, a serial entrepreneur, had done many successful biomedical devices ventures,” Martin says. “I had a coffee with Ian, and I put a vial of gel down on the coffee table, and I said, ‘what do you think?’. He looked at me and he said, ‘can you push it through a thirty-gauge needle?
“And so, off we went to the lab, and of course it is really, really easy to inject.”
The physical network of nanocellulose fibres is so easily injectable because, when squeezed through a small orifice, the fibres line up neatly and shoot through. Once they’ve passed through the needle, they self-reassemble, forming the three-dimensional network that stabilises the gel. It was a big breakthrough, Martin tells me, because injectable gels – used in cosmetic surgery, to treat osteoarthritis, and for other orthopaedic conditions – are difficult to make.
“Self-assembly is great because it means you don’t have to do much to it, and it allows it to have a really nice injection profile,” explains Dr Jane Fitzpatrick, ANFF’s current CEO.
That smoothness is great for doctors and nurses who need to exercise control over how much of the product is being injected, and the speed at which it travels through the needle and into the body.
The gel was so promising that investors are now shelling out money to take it to market. In February, major science investment company Uniseed announced it was co-investing with Bulugudu, amounting to a total of $2.6 million into a newly formed company called Trioda Wilingi, a spinout from the project which has the exclusive global rights to develop the novel injectable gel.
In Indjalandji-Dhidhanu language, Trioda Wilingi means ‘special grass’, says Saltmere. Bulugudu, the name of the Aboriginal corporation, means ‘strong’.
“We’ve integrated traditional knowledge of the plant and how it grows with the latest chemical nanotechnology advances, to create the beginnings of a new industry,” said Trioda Wilingi interim CEO Tim Case at the time of the announcement.
The spinifex will continue to be harvested on country by Indjalandji-Dhidhanu people who, through Bulugudu, own 51% of the IP, in an agreement with UQ.
“We’ve got a permit to take on our country, over 77,000 square kilometres,” says Saltmere. “We take the grass 125 millimetres off the ground, so the spinifex is still intact.”
Because so little is needed to make up the gel, and because the plants can regenerate, the community, which is based around the upper Georgina River and includes the remote town of Camooweal, where Saltmere lives, will be able to produce significant value from their land in a sustainable way.
In a specialised lab out on Country, he and his community are running tests on various other plants, melding culture with science to produce what he believes will be a major local industry. The hardy, arid-adapted spinifex, crafted through trial and fire over millions of years, is just the beginning.
“In Indjalandji-Dhidhanu culture, spinifex is a sacred thing,” says Saltmere. “It belongs to Country, and to us, that’s what ‘sacred’ means.”
Originally published by Cosmos as What is it about spinifex that’s got everyone excited?
Amalyah Hart has a BA (Hons) in Archaeology and Anthropology from the University of Oxford and an MA in Journalism from the University of Melbourne.