Story | 06/21/2023 12:05:00 | 7 min Read time

A wound dressing that does not need changing: A wood gel revolutionises wound care

Aurora Airaskorpi

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Wounds are painful for patients and burdensome for health services. One solution for their management can be found in Finnish forests. Hospitals have introduced a new type of wound dressing that takes advantage of the healing properties of wood.

How does a tree survive for hundreds, even thousands of years? Because it has an immune defence system just like humans. When the bark of a tree is damaged, resin is released at the wound site. Antibacterial resin protects the inner layers from microbes that could infect the wood and lead to decay.

Ointments made from resin have also been used by people for thousands of years to treat wounds. The 1900's were a time of another kind of innovation: cotton gauze was replaced by plasters and later by polyurethane foam bandages. Many of today's wound care dressings contain synthetic or animal-based ingredients, for which alternatives are once again being increasingly sought.

This has led researchers and the pharmaceutical industry to look back to nature. In addition to resin, wood also has other interesting ingredients. One of these is nanocellulose. It has been developed into a new type of wound care dressing that supports the natural healing of the skin and facilitates the treatment of difficult wounds.

Nanocellulose supports natural skin healing

Nanocellulose is produced when the fibres of the cellulose used to make paper are ground into small particles. We're talking billionths of a metre – you cannot see the fibres with the naked eye. When these nanocellulose fibres are combined with water, a hydrogel with revolutionary properties is created.

"Nanocellulose is easily malleable, its raw material is a renewable resource and it is non-toxic", lists Marjo Yliperttula, Professor of Pharmaceutical Biosciences at the University of Helsinki.

These are the reasons that got Yliperttula excited about nanocellulose research. Her research group is a pioneer in the field, even internationally.

In 2007, Yliperttula's team experimented with growing cells in a hydrogel made by UPM from nanocellulose. The hydrogel proved to be compatible with human cells. UPM developed the cell culture gel, which is used in research laboratories around the world.

The research also led to the development of a new wound care dressing that supports the natural healing process of the skin. This invention is also already in use: a nanocellulose dressing manufactured by UPM Biomedicals is used in Finnish hospitals to treat skin graft donor sites.

 

In the operating theatre, the best option wins

A skin graft is a procedure in which healthy skin is transplanted to an area of skin damaged by a burn, for example. In this case, the patient will have a second wound in addition to the original one. When treating patients, it is also important to ensure that not only the wound, but also the donor site heals.

"Patients often say that the donor site of the skin graft is the more painful of the two wounds", says Emma-Lotta Kiukas, a plastic surgeon working in the wellbeing services county of South Karelia.

The love for her local environment was the main reason why Kiukas adopted the nanocellulose dressing to treat her own wound patients.

"I was fascinated by the idea of a product being made just a few kilometres away from where I work", she says. The cellulose comes from Finnish birch, which is processed into nanocellulose at UPM's Research Centre in Lappeenranta.

The dressing is not changed periodically, instead the wound is allowed to heal under the disposable dressing.

However, a material being local and natural is not a decisive factor when making care management decisions. In the operating theatre, the focus is not on the material's environmental friendliness, but rather on patient friendliness, says Kiukas.

"We always try to find the most appropriate and cost-effective solution for each patient".

Hospitals have very limited resources, and materials and equipment are selected according to what works best and reduces the need for further treatment.

Wound dressings are used for the treatment of skin graft donor site wounds. The dressing is cut to the appropriate size and placed over the wound. The dressing is not changed periodically, instead the wound is allowed to heal under the disposable dressing.

The advantage of a wound dressing made from nanocellulose is that it can cover large areas of skin, according to Kiukas. There may not be healthy skin at the site of the skin graft to which the adhesive surface of a conventional dressing could adhere. It is important that the dressing stays in place.

"If you pull on the dressing before the wound has healed, even healthy skin can easily tear. This can affect the healing of the wound and cause the donor site to become inflamed".

Moving away from animal-based raw materials

Wound patients are a large patient group in healthcare, and wound treatment costs hundreds of millions of euros in treatment expenses in Finland every year. A dressing that comes off the wound on its own and potentially reduces the number of infections can help reduce the workload of the health service. 

"Having products that can save time frees up nursing time for other tasks", says Kaija Ojala from UPM Biomedicals.

UPM Biomedicals, which develops and manufactures wood-based biomedical products, is also interested in the many other possibilities of nanocellulose. In the future, nanocellulose could be combined with, for example, medicines or cells to help a specific area of the body heal faster. 

A locally administered medicine could reduce strain on the liver from ingesting medicines and ensure that the medicine goes where it's supposed to. The potential of nanocellulose in the development of such therapies is massive, according to both Yliperttula and Ojala.

However, developing new products is a long and multi-stage process, Ojala points out.

"Pre-clinical studies take two years, clinical trials another two years and a further two years to obtain a CE marking".

Another argument in favour of applications using nanocellulose is that they come from forests and not from humans or animals. European and US authorities are working to prevent the use of materials of animal origin. For example, the collagen commonly used in wound dressings is animal-based. The authorities' aim is based not only on animal conservation, but also on the will of the patients. 

"Patients may be interested in where the substances that go into their skin come from", says Ojala. No animals need to be sacrificed to make nanocellulose. It has also been found to be compatible with human tissues so that the body does not develop a rejection reaction. 

Many patients ask whether birch-derived nanocellulose can cause an allergic reaction in someone allergic to birch. "It can't", Ojala replies. The properties of birch are almost completely transformed when it is processed into nanocellulose.

The healing power of wood can therefore be relied on even in the 2020s.

 
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