Flat’s the way to do it2 May 2018
Graphene looks set to transform medical manufacturing, but getting it from the lab to the hospital is not easy. We investigate the promise and pitfalls of the new wonder material that could make life safer for patients all over the world.
On Friday nights, Andre Geim and Kostya Novoselov would go back to work and have some fun. Leaving their official research at the door, the duo would spend a few hours messing about in their lab at the University of Manchester. For a while, these ‘Fridaynight experiments’ were just that, but one evening, in 2004, the pair made an astonishing discovery.
By using sticky tape to remove flakes from a lump of graphite, then repeating the process over and over, they could create particles just one atom thick. Their laidback tinkering had paid off; Geim and Novoselov had isolated graphene.
From these unplanned beginnings, the material has sprouted into one of the great scientific hopes of our time. Its mix of toughness and flexibility makes it ideal for dozens of fields, from defence and agriculture to computing and solar energy. Meanwhile, scientists are working to incorporate graphene into the medical market, with wearable sensors a particular area of excitement.
Getting graphene from the laboratory to the production line has proved difficult, however, while concerns about its health risks refuse to subside. Nonetheless, medical research into the carbon continues unabated, and it is easy to understand why; graphene has the chance to explode the traditional medical device industry, saving time, money and lives on a remarkable scale.
Though scientists and journalists have eulogised graphene since it was first discovered, it is worth going over what makes the material so special. As Geim and Novoselov learned, it is a pleasingly simple substance. Like graphite in a pencil, or the diamonds in a ring, graphene is just a type of carbon. What makes it different is its atomic structure; while diamond and graphite have threedimensional structures, graphene is only two-dimensional. Its atoms are laid flat in a honeycomb shape, like balls on a pool table.
This is remarkable from a scientific perspective; the structure makes graphene the thinnest material scientists have ever discovered. You would need about three million layers just to reach the thickness of a single millimetre. This ultra-thin structure isn’t just for just for show, either. Because the carbon atoms in graphene are on a flat plane, the material can flex relatively easily without breaking apart. This makes graphene incredibly tough, some 200 times stronger than steel. Moreover, its unique structure gives it elasticity; it can be stretched by as much as 25% before it snaps and is so light that, according to one estimate, you could cover the whole of the US with just 2,000t of it.
At the same time, its unique atomic structure makes graphene a brilliant electrical conductor. No wonder the amount spent on research has leapt in recent years. Various agencies recently gifted the University of Manchester £61 million to build a swanky new research facility. In 2013, the European Commission announced a mammoth $1.3-billion graphene investment pot. As impressive as this is, it is small fry compared with what businesses are pumping into the industry. For example, IBM is putting $3 billion into graphene research over the next few years. All told, graphene is expected to become a $1-billion market by 2025.
Clinical researchers have been eager to step into this vast and expanding sector. It is easy to appreciate why: graphene has the potential to fix a range of medical problems. One of the most interesting areas of study involves so-called wearables. Because it is so light, scientists can easily integrate graphene into clothes, bracelets or patches, while its high conductivity means information gathered from its devices can be fired off quickly.
Scientists have already exploited all this in some fascinating ways. Earlier this year, a team at the University of Sussex mixed graphene with oil and water then channelled it through a tube, creating a baby-monitoring system. When the tube is even slightly stretched, the graphene forces the conductivity of the liquid to change. This sensitivity lets doctors immediately trace infant respiration rates or pulse changes.
Apart from its impressive accuracy, this system is far less invasive than traditional baby monitors. Rather than relying on clunky sensors, which have to be physically attached to the child and involve a tangle of wires, this graphene-based approach can be slipped round their wrists or even integrated into a vest. For their part, scientists working on the project are optimistic about where it could lead.
“We will eventually have a suit that the baby can wear, which will read out all vital information wirelessly,” explains Professor Alan Dalton, who headed up the research. “We hope to see this made available within two to four years.”
Similar work is happening on the other side of the world. Scientists at the Centre for Nanoparticle Research in South Korea recently developed graphene-based patches to monitor diabetes. Once again, graphene’s remarkable thinness recommends it to the task: at 250μm in diameter, and just 1mm high, the patches are too small to cause pain when attached.
After absorbing sweat from a patient, the patch then measures how much glucose the body contains. When blood sugar levels get too high, tiny microneedles automatically administer the patient with metformin, a drug that keeps it under control.
For Tim Harper, a consultant who focuses on graphene, these examples feed into broader trends across the health sector. As with similar developments elsewhere – for example in big data – graphene wearables are impressive for their ability to quickly gather up patient data. “For me that’s quite exciting, because it gets you into areas of preventative medicine,” he says. “I think where graphene can really make a difference is in providing basic data. That allows you to start correlating [data] to health outcomes, whether it is predicting falls, or [changing] compression bandages, or something in between.”
This is all good news, but the path ahead is not completely clear. For one thing, graphene remains frustratingly pricey. Despite being discovered 14 years ago, just 1g of graphene still costs about $100. To put this into perspective, the same amount of gold is worth $42. This makes producing graphene-based gizmos correspondingly expensive, a problem that seems to be impacting the industry. Several graphene companies have seen their returns languish, with the profits at one British start-up dropping by 30% over the past year.
– Professor Alan Dalton, University of Sussex
Another difficulty is specific to the medical industry. With the FDA and its European counterparts famously – and rightfully – strict about what can enter the market, researchers and manufacturers have a long battle to get graphene from the lab to the hospital ward. Continued worries about the material’s safety – tiny flakes might be able to enter the lungs – don’t help. For Harper, the concerns are typical for new ‘wonder products’ like graphene. “Usually, there’s a lot of hype,” he says.
“But once people actually start understanding the market – especially in the medical market, which is very highly regulated – then you really discover the real barriers to commercialising any of these things. There is often a disconnect between what is published by academics and what anybody in the commercial sector would view as realistic.”
A wider question is whether graphene is even necessary, particularly in fields like medical electronics, where decent alternatives, like silicone, have been around for decades. “For most applications, silicone is perfectly good enough,” says Harper. “It’s very hard to go to someone who has invested $1 billion dollars in a factory and tell them, ‘You have to throw all that away because graphene is coming.’ That displacement issue tends to be one of the biggest barriers [for graphene], unless you can demonstrate that it really is a step-change in performance or price.”
Race to development
Faced with these challenges, researchers are rushing to make graphene more appealing to manufacturers, even as they tinker with its mechanical properties. A team at the University of Glasgow recently developed a way of creating graphene 100 times cheaper than before, for instance. Increased use of the material, particularly in burgeoning Chinese and Indian factories, also promises to lower overheads. According to a 2016 study by Deloitte, the next decade could see the start of a ‘graphene era’ in which the material is cheap enough to enter large-scale medical manufacturing.
Harper agrees, noting that, “As these materials develop and people figure out better ways to produce things, the price will fall.”
Though full graphene medical manufacturing is still a way off, the FDA is already performing several studies into its safety, suggesting that regulators are taking the material seriously. This is just as well, given all the exciting graphene-based work being done. Wearables are only one avenue of interest. At the end of last year, scientists in Sweden displayed the prototype of graphene detector for terahertz frequencies, increasingly used as a safe alternative to X-rays. Other researchers are using graphene for more direct medical applications, such as to treat cancer or sequence genes.
Just as with the discovery of graphene in 2004, it is difficult to know where all this could lead. But as researchers keep exploring this incredible material in new ways, the future of graphene seems bright – even if the road from research to reality is not as smooth as some scientists might hope.