A better band-aid?

Skin loss can be life-threatening for victims of severe burns. For example, people who lose 20 percent or more of their body skin need immediate protection from infection, as well as a bandage that promotes quick healing.

Ideally, the bandage should cover the wound, support healing, prevent infection, and then dissolve away, Jack G. Winterowd, a polymer chemist at Weyerhaeuser Corp. in Tacoma, Wash., working with physicians at the University of Washington in Seattle, has been experimenting with just such a bandage.

Made of naturally occurring chitosan derived from crustacean shells (SN: 7/31/93, p.72) and calcium alginate derived from seaweed, the bandage slowly releases an epidermal growth factor that supports natural skin healing at the wound site. It also fends off infection-causing fungi and bacteria.

"Showering the wound steadily for several days with low doses of growth factor" derived from mouse salivary glands, Winterowd says, causes the skin to begin regenerating. The steady shower comes from growth factor microencapsulated in calcium alginate particles embedded in the chitosan film.

In the presence of alkaline saline and lysozymes at the wound site, Winterowd says, the bandage's "hydrogel film"--similar to soft contact lens material -- simply dissolves. Animal tests, he says, will begin soon.