There are more uses for crabs than a good shore dinner. Researchers at North Carolina State University have developed a biodegradable wound dressing for burns made from chitosan, a natural fiber extracted from crab shells. In tests on pigs, the three-layered bandage protected the wound from bacteria as the inner two layers were absorbed into the skin.
Burn dressings now in use must be regularly reapplied, which disturbs the wound and can be quite painful if scabs adhere to the dressing. But chitosan, used in the bottom layer of the new bandage, is easily absorbed by the human body, so it need never be removed. In fact, it acts as a cellulose-like scaffolding on which new cells can grow. And because chitosan is known to resist funguses, microbes, and viruses, it actually speeds healing. North Carolina State textile professor Samuel Hudson says the fiber also suppresses the undesired cell growth that causes scarring.
The second layer is made of a polymer that also degrades and becomes part of the skin. It has the consistency of cellophane and acts as a second line of defense after the chitosan breaks down. The outermost layer is a cotton gauze that, like traditional dressings, is changed occasionally. The researchers, who presented their bandage at the American Chemical Society's annual meeting in August, said further research is needed to perfect the balance of moisture in the bandage to promote healing. They should have no trouble finding supplies. Chitin, the base of chitosan, is the earth's second most abundant organic resource after cellulose.