From the city that brought us the splitting of the atom, the earliest programmable computer, the contraceptive pill and the first test-tube baby comes a Nobel Prize-winning discovery that just keeps on giving. Paul Quigley tells the story of graphene
Nestling unassumingly on an anonymous side street in the heart of city’s academic district is the University of Manchester’s physics faculty – where it happened. Some 12 years ago, two curious research physicists were playing around with pencils and sticky tape late one Friday evening, much as driven academic researchers do when slaving away in the lab in a post-quantum material world of quarks, strangeness and charm. However, that evening in Academiopolis Mancuniae was different. And not just because it wasn’t raining in Manchester. Almost by accident, the two – Andre Geim and Konstantin (Kostya) Novoselov – made a quite extraordinary discovery.
In something akin to Isaac Newton’s ‘apple-on-the-head’ moment via one of Valerie Singleton’s ‘sticky-back-plastic’ creations on Blue Peter, the two Russians had managed to prove unequivocally that the Large Hadron Collider was no longer the only game in town in bleeding-edge post-quantum physics.
After having successfully levitated a frog using magnets several years earlier, the two physicists were playing around with chunks of graphite and rolls of sticky tape, consecutively peeling off tiny flakier layers of the material. Novoselov, now Professor of Physics at Manchester University, picks up the story. ‘We started to work with carbon graphite flakes. It was a “Friday evening experiment’’. We didn’t even know that graphene existed. If you’d asked me then, I’d have said it was impossible to get a monolayer of anything. We were trying to make them thinner and thinner,’ he explains. ‘Monolayer and bilayer graphene was quite an achievement but it was a process. We knew we had something very special in our hands from the very beginning.’
Indeed they did. Three hundred times stronger than steel, harder than diamond, more conductive than gold or copper, virtually translucent (97.7 per cent), inert, more flexible than rubber – and yet – only one atom thick, graphene is a unique material the like of which had never before been formulated. Unique not only because it is sterile and antimicrobial, graphene is also now being studied as a miracle ‘wonderstuff’ for all manner of medtech applications as diverse as prosthetic retinas, cardio-surgical and brain implants, for biosensors of all kinds, as well as myriad uses in toxicology, drug delivery and tissue engineering. It is even being earmarked for breakthroughs in cancer therapy. Already this year, scientists at the University of Manchester have discovered further medtech applications for graphene in the form of state-of-the-art terahertz lasers which, with far less radiation dosages to patients, may yet come to replace existing x-ray technology. Graphene looks set become a revolutionary catalyst that is pivotal to constructively disrupting technology on so many levels.
When it comes to medical technology and devices using graphene, the possibilities are almost endless, and innovation is already well under way for many new products and services. Just down the road at Manchester’s new National Graphene Institute, Dr Cyrill Bussy, Lecturer in Nanosafety at the university’s Nanomedicine Lab in the Faculty of Medical and Human Sciences, is hard at work turning Geim and Novoselov’s superlative discovery into real-world, tangible solutions.
The potential for what is expected to become a multibillion market over the next decade is driving investment and research labs around the world into a frenzy of experimentation and clinical trials. Graphene has already become part of the fabric of post-industrial materials science, forming the basis for the medtech innovation of tomorrow.
Nigel Syrotuck, Product Design Engineer for Starfish Medical in Canada believes that the most likely next use for graphene is in sensors. ‘Specifically,’ he says, ‘wellness devices such as personal health monitors, where highly specialised diagnostic machines that can harness graphene’s unique attributes will create more accurate, more specific and smaller tools.’ According to Syrotuck, graphene will be accompanied by more innovation. ‘The other interesting phenomenon is the appearance of numerous competing materials such as boron and diamond-structured carbon that have similar properties, structures and applications,’ he says. ‘It looks like graphene is not just a “wunderkind”, but also a trendsetter.’
Dr Bussy concurs with Syrotuck’s insights into the 2D catalyst theme that graphene has engendered. ‘Graphene-based materials are among the latest nanomaterials explored for their potential in the biomedical field. While many groups around the world are comparing graphene-based materials to other nanomaterials for drug-delivery applications, trying to figure out whether graphene-based materials are performing better, and how unique graphene can be, it is probably in the area of biosensors and wearable devices that graphene will find its place, at least in the short term.’ According to Bussy, graphene’s unique combination of properties, such as conductivity together with flexibility, make it a perfect solution for unmet medical needs in devices based on wearable, flexible electronics that transmit real-time information to support self-management of health and wellbeing, and to facilitate timely interventions, such as insulin injections. ‘Scientists at the University of Manchester have even started to think about healthcare monitors that would be directly printed onto skin,’ Bussy reveals.
As mentioned earlier, one of the big hopes for graphene is related to serious eye conditions and diseases. Dr Bussy explains that this is also widely appreciated among the graphene research community, and moves are already afoot to address some of the key underlying issues ‘in the case of a defined application such as prosthetic retinal substitute,’ he says. Bussy believes that the biocompatibility of graphene is the key issue, rather than pure toxicology. ‘It means that instead of looking at reaction of cells in relation to a route of human exposure, scientists will adopt a slightly different approach,’ he explains. ‘So in the case of graphene as a component of a prosthetic retinal substitute, scientists will need to ensure that cells growing around the graphene-based implant/electrode array are not affected in any way, meaning that their functions are unchanged by the implant’s presence.’
While the potential for retinal implants is great, the practical challenges facing such a life-changing reality are even greater, as Professor José Antonio Garrido, head of the Advanced Electronic Materials and Devices group at the Catalan Institute of Nanoscience and Nanotechnology in Barcelona, is discovering as he works on the optical capabilities of graphene. ‘It is true that graphene is being explored in retinal implants. We believe that because of its unique properties – its flexibility, mechanically stability and excellent electronic performance, graphene can play an important role in brain implants, including retinal implants.’ According to Dr Bussy, graphene has other special benefits that medtech can harness. In the area of electrode array, bringing graphene’s unique properties of transparency, flexibility, conductivity and resistance to bear are a key focus. ‘The only requirement in terms of biocompatibility testing is to make sure that using graphene instead of the currently used material will not change the biocompatibility of the retinal implant,’ says Bussy. ‘Based on what we know so far in terms of the interaction of cells with the graphene-based substrate (the surface on which they can grow), it would be very surprising if graphene is not biocompatible for this application.’
The burgeoning interest in the prospects for real-world products and applications for this the carbon-based ‘wonderstuff’ has even got the bureaucrats in Brussels jostling for position to exploit graphene’s economic and industrial potential, investing a cool €1 billion in funding over the next decade for a programme that bears its name. The EU’s Graphene Flagship is a 10-year endeavour with more than 150 partners from many nations around the continent.
Professor Garrido’s activities are part of the EU Graphene Flagship programme. He is currently working on developing graphene-based technologies to fabricate flexible implants for both the human central and peripheral nervous systems. He explains: ‘We are currently designing and fabricating flexible arrays of graphene transistors on biocompatible polymer substrates that are able to detect the electrical activity on the surface of the brain. The technology we are developing, in contrast to that currently used and based on metallic electrodes, allows a much higher integration density – that is to say, sensors per unit of area – and better spatial resolution with smaller sensors.’ Professor Garrido expects that such graphene-assisted technology will be used for applications related to epilepsy, control of artificial limbs – and retina implants.
Already, real-world graphene products have hit the market in related industries. Commercial products that use graphene or graphene-related materials are used in paint and coatings. Professor Garrido says that products requiring more advanced technology developments, such as flexible touch- screens, sensors, etc, aren’t far away from commercialisation. ‘Other products, with a much higher level of technology developments, might need some more time,’ he concedes. Nevertheless, there are already prototypes of devices that have been tested and shown to outperform current technologies. ‘At the moment, it’s a matter of improving on reliability, stability and production yield,’ he explains.
But before such wondrous medtech miracles can move from virtual-reality models to reality-based solutions, Professor Garrido highlights some of the main hurdles that scientists and engineers need to overcome. According to Garrido, the meticulous scrutiny of clinical trials, and of type approval, form the basis of this phase. ‘The future devices will be rather complex structures fabricated using different materials – polymers and metals – in which graphene might play some particular role,’ Garrido says. ‘This will take advantage of its flexibility, optical transparency and excellent electronic properties.’
Other areas where Professor Garrido sees graphene research making major strides for medtech outcomes include its great potential in biosensors, both for low-cost, disposable versions and for high-end, highly sensitive, specific ones. Furthermore, Garrido says that drug delivery and therapeutics based on graphene nanomaterials are also very appealing fields for research which he says are already growing very rapidly.
More than just a panacea for myriad medical and clinical challenges, graphene has a massive potential in all manner of scientific and materials science, as well as the life sciences that researchers and product developers are now hard-pressed to keep apace with, such is the sheer scale of graphene’s constantly evolving properties and practical application potential.
As graphene unleashes waves of innovation across the wider medtech space, it looks set to join most of the other great scientific discoveries of the last century, those things like atoms, DNA, radio frequency, neutrons, x-rays, dark matter – things that can’t be seen by the naked eye. So perhaps unsurprisingly, as the next millennium spans out into the distance, this voyage of discovery is not yet over for Kostya Novoselov either, who is already back in his scientific sandbox hard at ‘work’, playing once again at prising open the doors of perception that graphene has blazed a trail for. He’s looking at applied superconductors and searching for more of the ferromagnetic mischief that graphene has helped shine a light onto. Chances are he’ll find something. And as this Friday evening’s traffic heads homeward and the city streets around the National Graphene Institute fall silent, raindrops begin to spatter the grey pavements like random, flat shiny wet lattices. After all, this is Manchester, where pigs may yet fly as levitating frogs have done already. And if the recent past is anything to go by, at this rate, it’ll soon be raining cats and dogs, too.
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