Medical Breakthroughs: Wound-Healing Crabs


Monday, November 22nd 1999, 12:00 am
By: News On 6


Scientists have developed a three-layer, biodegradable wound dressing that can improve the healing process of third and fourth-degree burns. The new dressing, created by North Carolina State University textile researchers, incorporates layers of chitosan, a natural fiber extracted from crab shells, and synthetic polymer compounds under a gauze layer. Preliminary studies on pigskin showed the composite wound dressing increased the healing rate and protected the wound from bacteria and other threats as the two inner layers are absorbed into the skin.

Wound Dressing Layers: Tests using the dressing showed it was a viable option for solving some of the problems created by other dressings currently in use. Researchers say the crab-based composite can:

A) Decrease the healing time
B) Increase the healing rate
C) Reduce the pain
D) Produce less scaring

More importantly, the biodegradable composite helps the skin grow back. The wound dressing consists of three layers. Starting closest to the wound, they are:

1) Chitosan layer
2) Polyester film layer
3) Gauze layer

Benefits: The inner layer of the composite dressing actually became part of the healed skin. Only the gauze outer layer must be removed and discarded. The process doesn’t disturb the wound. Re-application of dressings that disturb the wound can be uncomfortable for patients, especially when dressings attached to healing skin take scabs off as they are removed. Chitosan, used in the layer closest to the wound, is known for its anti-fungal, anti-microbial, anti-viral and wound-healing process. It is easily converted to a strong, flexible fiber and the human body absorbs it easily. Chitin the base of chitosan, is the second-most abundant organic resource on earth. From shell waste, producers can harvest chitin and chitosan to make valuable products for the medical, food, fiber and textile industries.

For the second layer of the composite, the research team tested films made of two different biodegradable polymers. The second layer protects the wound and prevents the outer gauze layer from sticking to the wound. It is the second line of defense against bacteria that may try to invade after the chitosan layer breaks down. This polymer film layer, about the consistency of cellophane paper, also degrades and becomes part of the healed skin. The outermost layer of gauze absorbs fluids and must be changed periodically.

For more information, contact:

Sam Hudson
North Carolina State University
College of Textiles
Box 8301
Raleigh, NC 27695-8301
E-mail: sam_hudson@ncsu.edu