Material gains: the evolution of textiles4 June 2015
As chronic diseases become more prevalent, the constantly evolving field of medical textiles offers a multitude of opportunities within healthcare. Professor Stephen Russell, director of the Clothworkers’ Centre for Textile Materials Innovation for Healthcare at the University of Leeds, explains how fibres and fabrics are affecting the course of medicine.
When asked to think of cutting-edge materials, few people are likely to mention textiles. The realm of knitted, woven and braided materials seems old-fashioned, a far cry from the fast-paced world of medical innovation. After all, when you're used to hearing about biodegradable polymers and antimicrobial silver coatings, fabrics of this kind must appear to be very low-tech.
This, however, is a misconception. Medical textiles - comprising fibrous and nonwoven materials - are valued for their flexibility and strength and fundamental to the function of numerous devices. To this end, they constitute a rapidly advancing field. As healthcare needs change, we are seeing renewed demand for textile-based products across a staggering array of applications.
As one of the leading academics in this arena explains, the list is hard to narrow down. Professor Stephen Russell specialises in nonwoven materials technology and is director of the Centre of Technical Textiles at the University of Leeds. While his multidisciplinary department encompasses transport, energy and the environment, healthcare is one of its key priorities, and its medicine-focused research portfolio leaves few areas unchecked.
"The core research programme deals with extracorporeal devices, particularly blood filtration and dialysis; implantables, such as scaffolds for tissue repair and regeneration; external devices, notably chronic wound dressings; continence management including ostomy devices; and methods of reducing transmission of infection," he says.
"Other specific applications include sutures, artificial ligaments and tendons, hernia repair patches, synthetic skin substitutes, pressure garments, prosthetics, drug delivery, surgical gowns, respiratory filters, operating room drapes and antimicrobial wipes."
In short, while textiles may sometimes be hidden from view, they are integral to today's medical marketplace. And far from being an antiquated area of focus, they are ideally suited to a very timely set of challenges.
"The population in the developed world is aging, and while life expectancy is increasing, so, too is the prevalence of long-term disease, and conditions such as obesity, diabetes and chronic kidney disease, as well as end-stage renal disease," points out Russell. "These factors intensify the need for new interventions in medical textiles that provide better therapeutic benefits and reduce patient morbidity."
The inevitable corollary of an aging population is a healthcare system under strain. When more people suffer from chronic diseases, the costs of managing those conditions are likely to soar, and budgets and personnel will feel the pressure.
If textiles can deliver improved performance - to a point at which less treatment time is needed - it will translate to lower price tags.
For instance, around 41,000 people in England currently receive treatment for kidney failure. While this is only a small proportion of the total number of NHS patients, it costs the organisation a lot of money to care for them.
"Although end-stage renal failure affects only 0.05% of the population, it consumes 1-2% of the annual NHS budget," says Russell. "Patients requiring a kidney transplant frequently have to wait a very long time before a compatible organ from a living donor becomes available for transplant. Meanwhile, their lives are disrupted by the need to receive regular haemodialysis every week."
As a response, his team is working on advanced blood filtration media. These will target toxins that are difficult to remove during conventional haemodialysis, therefore reducing the number of hospital visits that kidney patients will need to make.
The researchers are also looking to address the problem of transplant rejection, which occurs when donor and recipient have mismatched blood groups. Developing a filter medium that can selectively remove the incompatible antibodies will enable many patients to receive transplants from previously incompatible blood types. This, in turn, will slash waiting lists.
Another area of focus is dispersible pouches for patients living with a colostomy, or stoma. Affecting more than 100,000 people in the UK, the latter is a surgically induced opening in the bowel that enables stool to drain into a pouch.
"Stoma patients are faced with the duty of disposing of their pouches, which is unpleasant, and can lead to social withdrawal," says Russell. "We've been working on making these devices fully dispersible in the toilet, so that they can be flushed away, rather than discarded as part of domestic rubbish."
Fabrics must not only be strong enough to stay intact while on the body, resisting the build-up of contained fluid under pressure, but also to break up quickly when flushed down the toilet. Despite these technical challenges, the endeavour has so far been successful, and Russell's team is now developing the technology for commercial use.
After all, honing materials science expertise is one thing; developing fully applicable products is quite another. This means considering safety, storage and environmental stability, from the earliest stages of research.
It also means staying abreast of the medical devices landscape as it evolves, including the inevitable regulatory issues."Our work relies on advancing textile science and engineering to improve the performance of products used in healthcare," says Russell.
"To do this effectively, we involve clinicians and nurses from the outset, as well as experts in regulatory procedure, to enable us to accurately define specific, unmet needs and technical research challenges, and to minimise the risk of late-stage failure."
These challenges are particularly acute where polymers are being used. Different plastics have different applications, properties, performance characteristics and costs, not to mention different regulatory implications. The choice of polymer materials is critical for this reason, and will ultimately affect not just how well the textile works, but also how easily it transfers from the lab to real-life hospital settings.
Although Russell and colleagues are based in the UK, they are also interested in applications further afield. As well as addressing the chronic conditions common in the developed world, they are keen to ensure global access to healthcare products, and their work involves collaboration with a wide range of international organisations.
"This is something we consider carefully, particularly as urbanisation continues to create major challenges in terms of access to clean water, sanitation and healthcare in Africa, Asia and Latin America," he says. "Great strides have also been made in protecting people from insect vector-borne diseases, such as malaria, using protective insecticidal nets, but dealing effectively with growing insecticide resistance poses new challenges."
Providing such nets is a top priority for the World Health Organization. Commonly made from polyester, polyethylene or polypropylene, they are treated with pyrethroid insecticides, which pose minimal health risk to humans, and only slowly lose their efficacy. The concern about pyrethroid resistance - borne out by recent studies - means materials scientists and medical researchers will have to work hard to find new solutions.
Looking ahead, Russell is excited about the possibilities for several nascent grounds of research. While these have yet to be developed into commercial propositions, they hold great potential, and may one day provide some much-needed benefits to healthcare.
"We're excited about our research dealing with manufacturing new functionalised collagen fibres with remarkable mechanical and wet-stability properties, making them very suitable for guided bone regeneration, particularly in dental surgery," he says. "Elsewhere, research on fibre-based drug delivery is developing new strategies for controlling pharmacokinetic release profiles that are otherwise difficult to achieve."
A further area of focus is wound management. Given rising rates of diabetes and obesity, many more people will suffer from chronic wounds that are slow to heal, including venous leg ulcers and pressure sores. The department is working on managing exudate and microbial activity in the wound, which is an important facet of infection control. One of its projects has successfully identified alternative microbial materials that can be integrated into fibres, with a view to controlling the formation of biofilms associated with delayed healing.
"Developments in textile materials like this take a while to reach the healthcare setting, but we are increasingly motivated by the need to stratify and ultimately personalise the structure and physical properties of medical textiles in response to patient needs, instead of the one-size-fits-all approach," says Russell.
Medical textiles, occupy an area that is difficult to pin down. Perpetually evolving in response to new healthcare challenges - not to mention the growth of more personalised medical paradigms - these fibres and fabrics present a range of opportunities.
As demand soars, we can expect textile manufacturers to keep upgrading their offerings. From blood filtration to ileostomy products, and from wound dressings to prosthetics, the call for safe, inexpensive and efficacious materials will only grow stronger. It is clear that the field of technical fabrics is far more than just bandages and gauze.
Research at the Clothworkers' Centre for Textile Materials Innovation for Healthcare
- Blood filtration: millions of blood transfusions are carried out every year around the world, but sophisticated, fibre-based filters are required to ensure a safe and consistent blood supply. The centre is also working on filters that enable improved therapeutic treatment for patients where selective removal of unwanted compounds is required to manage, or treat, life-threatening conditions, such as kidney disease.
- Wound management: with an aging population, chronic wounds are a major (and increasing) problem globally. These include, but are not limited to: venous leg ulcers, pressure sores and burn injuries. Dressings that are more interactive and can manage biofilms, enzymatic activity and ensure controlled delivery of drugs to the wound site (where appropriate) are promising areas of development in this field.
- Continence management: millions of people have a bladder control problem that can negatively impact their quality of life. Professor Russell and his colleagues aim to significantly increase device disposal options for patients, carers and healthcare professions with technology that is capable of enabling discrete, leakage resistance, and fully toilet-flushable products. Textile research is also underway for combating odour, reducing bacterial activity which could lead to infection and skin irritation.
In addition to these areas, projects connected with other fields of healthcare such as surgical implants, tissue repair and regeneration, assistive technologies and protective clothing are also under way.