Wound care


wound dressings, however, are a bit more complicated in comparison, as they are designed around wound healing and changes that can happen in the healing process and selected for use based on a number of factors, such as size, volume of exudate and infection. Hydrogels are one such modern dressing material that is increasingly receiving attention for their high water content and biocompatibility, and subsequent wound-healing abilities. Hydrogels offer a number of advantages for wound healing and are subject to much research and development. “When applied over a lesion, these special gels can promote healing by absorbing discharged fluids (exudate) and keeping the wound protected, well-hydrated, and oxygenated,” explains Ryota Teshima, Department of Chemistry, Graduate School of Science, Tokyo University of Science. Known as ‘moist wound healing’, he explains, hydrogels can either be natural or synthetic, whereas synthetic materials can offer highly modified physical attributes and adhesive characteristics where natural hydrogels exhibit enhanced biocompatibility and biodegradability in comparison. “There’s some disadvantages with natural drug materials in that we don’t understand their chemistry and structure,” adds Kris Killian, associate professor, School of Materials Science & Engineering and School of Chemistry, University of New South Wales. “This makes it difficult to discern what’s going to happen when we use them, because they’re just too complex.” Killian points to its immunogenicity when derived from animals as an example, where they can elicit an unwanted immune response. Synthetic materials offer a number of advantages as you can control the chemistry and properties, so it’s easier to manufacture with a reduced negative response. “The negative is that we’re not as good as Mother Nature,” he admits “So most of the time when we make a synthetic material to mimic a natural material, it just doesn’t work as well.”


Faster and wider wound healing This is something Killian’s lab has set out to solve: “Hydrogels are being used in bandages for wound healing and in clinical settings at the hospital,” he explains, “But it’s going to be a type that’s derived from a natural material that has all these negatives, or a synthetic one that doesn’t mimic biology.” His lab, therefore, has been searching for new materials that mimic biology, and thanks to his students they used computational tools to design something unique. The interesting thing about this model, Killian explains, is that it is made from natural materials, a short peptide made of 10 amino acids that looked to form a gel naturally that hadn’t previously been reported. While they predicted the peptide would assemble into a gel in the computer model, what they hadn’t anticipated was its antimicrobial properties that could


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kill bacteria while supporting human cells. “Bacterial cells will die when they get into contact with it, but the cells in our skin, in our body, love this stuff. They recognise it as being related to a natural material,” says Killian. “Now we have something that we can make synthetically in the lab, which will make it much more useful for manufacturing and for application.” The hydrogel has some interesting attributes, he continues, that are better than nature. For instance, it is self-healing on a short timescale and becomes a liquid when applied to the site before forming a rigid gel to protect the wound. While Killian’s hydrogel has yet to be fully tested,


, which is a familiar ion in our bodies.” Alginate also has the added bonus that it can be extracted from washed up seaweed and can contribute to the UN’s Sustainable Development Goals, he adds. As Teshima continues, many developed hydrogels for wound care have adhesive properties to skin tissue so they follow its movement, stretch and can expand the wound once it swells up after absorbing exudates. “This not only could cause pain to the user but also may put them at higher risk of bacterial infection due to the wound area expansion,” he adds. It’s necessary then to experiment with hydrogels to effectively treat wounds without interfering with the wound healing process. Alginate is not adhesive to cells or skin, he


) to form a hydrogel. “This reaction is fascinating because a biopolymer with high biocompatibility can be easily made into a hydrogel with Ca2+


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he’s hopeful for its potential applications in wound care. For instance, he points to recent animal testing as an example where other materials have helped form new tissue and help rebuild the wound. That is what he and his lab are hoping for, and with the hydrogel’s antimicrobial properties this could also help tackle the increase of antibiotic-resistant bacteria that is a huge problem in medical care at the moment. “The fact that it has these really interesting mechanical properties suggests that it could be used in innovative ways that currently aren’t possible,” he adds. “So, we’re really hopeful that it will allow wound healing to happen faster and over a larger volume.” Teshima, on the other hand, lead author of ‘Low-adhesion and low-swelling hydrogel based on alginate and carbonated water to prevent temporary dilation of wound sites’ in the International Journal of Biological Macromolecules, has been developing his natural hydrogel since high school. Seeing its potential in wound healing, he followed this through to his research to form his hydrogel. “This hydrogel is composed of a network of biopolymers called alginates. Alginate is a natural polysaccharide polymer extracted from brown algae and is a sticky seaweed,” he explains. This polymer has an interesting reaction whereby the carboxy groups in the polymer react with calcium ions (Ca2+


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