Prickly old spinifex grass, a global Golden goose? Who’d have thought it?
For millennia, Australia’s indigenous owners have used native grass spinifex, ubiquitous in arid areas, to make houses, fish traps and smoke signals, and have extracted its sticky resins to use as ‘glue’ in making tools and weaponry.
Now, a team of University of Queensland researchers led by Professor Darren Martin from UQ’s Australian Institute for Bioengineering and Nanotechnology (AIBN), working with the indigenous custodians of north-west Queensland’s arid Camooweal region, have found potentially lucrative new uses for the hardy outback grass.
The project team has used nanocellulose extracted from native spinifex to make super-thin, sensation-transmitting latex.
From it, they’ve just created a better condom. A much, much better condom.
And that’s just the tip of the proverbial iceberg – or should we say, the nanocellulose wave on a vast outback ocean of spinifex?
What is spinifex?
Perennial hummock grasses in the genus Triodia, commonly known as spinifex, dominate the vegetation across more than 20 percent of the Australia, occurring in all states bar Tasmania. They grow on the low-nutrient soils of sandy plains and on low, rocky mountain ranges in the arid inland, as well as on rocky coastal outcrops.
Triodia has awl-shaped pointed leaves, the tips of which are high in silica.
What is nanocellulose?
Nanocellulose – consisting of long fibres of cellulose, each only a few nanometres (billionths of a metre) thick – is an unusually strong and lightweight natural material.
It has been the focus of much recent research – not surprising, considering that its properties make it exceptionally well suited to an array of applications: in medical dressings; for cleaning up oil spills; and as a component of flexible electronic displays.
What’s so good about spinifex nanocellulose?
Professor Martin said in a February 2016 UQ news release that the spinifex nanocellulose improved the physical properties of latex ‘significantly’.
“The great thing about our nanocellulose is that it’s a flexible nano-additive, so we can make a stronger and thinner membrane that is supple and flexible – which is the Holy Grail for natural rubber,” Professor Martin said.
Added to latex, the nanocellulose extracted from spinifex resulted in significantly stronger and thinner condoms capable of transmitting tactile sensations more effectively without potentially harmful direct contact.
The burst test
The UQ team tested its new latex formulation reinforced with spinifex nanocellulose in condoms made on a commercial dipping line in the United States, conducting ‘burst tests’ in which the spinifex-fibre-reinforced condoms were inflated to different volumes under varying amounts of pressure to ascertain their flexibility, strength and durability. Results were encouraging.
“We got on average got a performance increase of 20 percent in pressure and 40 percent in volume compared to the commerciail latex control sample,” Professor Martin said.
And with some judicious tweaking, it’s likely the team can make an even thinner, better condom.
“With a little more refinement, we think we can engineer a latex condom that’s about 30 percent thinner and will still pass all standards, and with more process optimisation work we will be able to make devices even thinner than this,” Professor Martin said.
“[In late 2014] we were able to get down to about 45 microns on our very first commercial dipping run, which is around the width of the hair on your head.”
The nanocellulose extraction process
According to AIBN’s Dr Nasim Amiralian, extracting nanocellulose from native spinifex is neither costly nor difficult – it can be done using an efficient method well-known in chemistry, combined with high pressure.
“You would firstly hedge the grass, and then it would be chopped up and pulped with sodium hydroxide – and at that stage it just looks like paper pulp,” Dr Amiralian explained.
“Then you hit it with mechanical energy to force it through a very small hole under high pressure to peel the nano-fibres apart from the pulp, into nanocellulose happily suspended in water and ready to add to things like water-based rubber latex.”
Spinifex nanotechnology built on ancient Aboriginal practices
The beneficial uses of spinifex (Triodia), and of spinifex resins in particular, are well known to Australia’s traditional owners.
For millennia, they’ve used the natural resins of this hardy, ubiquitous grass to make an effective adhesive for use in tool- and weapon-making, Professor Martin noted. “Spinifex resins have been used traditionally for attaching spear heads to their wooden shafts,” he said.
The Indjalandji-Dhidhanu people, traditional owners of the Camooweal region, have been advising the UQ researchers throughout the spinifex project.
So integral is their input to the project that in April 2015, the University of Queensland signed an agreement with the local Dugalunji Aboriginal Corporation to recognise the area’s traditional owners' long-established knowledge of spinifex and ensure the DAC has ongoing equity and involvement in the commercialisation of any resulting technology.
DAC managing director Colin Saltmere said that the corporation hoped the new technology would bring economic opportunities to the vast tracts of outback Australia in which spinifex thrives.
"It's high time we see an industry that Indigenous people are involved in," he said.
"The mining boom has stopped and it will eventually come back one day, but as every economist has been saying, we need to start looking at diversity."
The economic and marketing implications
So far, it’s been tested in condoms but down the line, the UQ-DAC team’s spinifex-nanocellulose project could have other potentially profitable uses.
Spinifex is “a super-tough plant and it has evolved to survive under incredibly hot conditions,” Professor Martin said. “The good news for us engineers is the plant retains water; it has a very open structure and you can break the thing apart very easily into these long nanofibres that have really tough properties and look to be really useful for a whole number of things.”
Professor Martin reckons the benefits of the new nanocellulose technology will likely interest latex manufacturers across a multi-billion-dollar global market. “Rather than looking at increasing the strength, companies would be looking to market the thinnest, most satisfying prophylactic possible,” he said.
“Likewise, it would also be possible to produce latex gloves that are just as strong, but thinner, giving a more sensitive feel and less hand fatigue to users such as surgeons.
“Because you would also use less latex, your material cost in production would potentially drop as well, making it even more attractive to manufacturers.”
UQ’s commercialisation company UniQuest is providing support and funding for developing the new nanocellulose technology, with funding via its Pathfinder initiative.
A solution that could benefit millions
UQ Vice-Chancellor and President Professor Peter Høj said the AIBN’s spinifex project is a prime example of innovative research that can be translated into “tangible solutions that create positive change”.
“At the heart of our research at UQ, we are aiming to harness research insights to engineer the next generation of products and solutions. This completes the laboratory-to-market lifecycle that can deliver benefits to millions.
“Research like this has great potential to make a difference in the fight against HIV and AIDS and other global issues in healthcare.”
A new industry for outback Australia and its traditional custodians?
Dugalunji Aboriginal Corporation’s Colin Saltmere said the technology is an opportunity for the project’s Indigenous partners to establish themselves as leaders in the area of spinifex harvesting and processing, and the supply of nanocellulose and other spinifex-derived products.
“There are strong hopes of cultivating and processing spinifex grass on a commercial scale, bringing economic opportunities to the remote areas across Australia where it thrives,” Saltmere said.
“We’re very excited by the prospects of commercialising the technology to provide an entirely new industry to regional Australia.”