New bandage for non-healing wounds

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http://www.wired.com/news/medtech/0,1286,57234,00.html A new smart bandage, designed to selectively pinpoint and absorbdestructive enzymes oozing from non-healing wounds, may soon become astaple in hospital supply cabinets.By eliminating these enzymes, the new cotton dressing accelerates thehealing process for bedsores, diabetic foot sores and other woundsthat resist conventional treatments.The potential market for the dressing is promising, its makers say.More than a million Americans suffer from non-healing woundsannually, at a cost of $750 million.The smart bandage's ability to meet this market need rests on itssuccess in targeting an enzyme called elastase."Elastase is designed to kill bacteria in an infected wound and helpclean out tissue that is devitalized," said one of the collaboratorsin the project, Dr. Dorne Yager of the Department of Surgery at theVirginia Commonwealth University.The trouble is that non-healing wounds have an excess of elastase --more than 20 times the normal level -- and in these quantities it canturn nasty."If these enzymes are over-exuberant, then they do damage to healthytissue, as they can't tell the difference between healthy andunhealthy tissue," Yager said. "This slows down the healing process."The job of the new bandage is to remove this excess elastase, butstill retain qualities of the cotton such as absorbency and airpermeability. The smart-bandage team accomplished this by alteringthe chemical structure of the cotton."We modified the cotton's cellulose in such a way that it binds theenzyme," said Dr. Vincent Edwards, a chemist in the cotton textilechemistry research unit of the Agricultural Research Service. Edwardsis the lead researcher on the project.Yager said the idea was to make simple changes in the cell structureof the cotton so that it absorbs in a specific way."The cotton's cellulose is given a negative charge," he said. "As theelastase has a positive charge, the cotton acts as a magnet andabsorbs the elastase."Another advantage of the smart bandages is that they can bemanufactured in a regular cotton mill so the ultimate cost will bekept within reasonable limits."One of the real virtues of the product is that it is going to bevery cheap," said Yager, who explained the new dressings will add acouple of cents a pound to the cost of bandages now on the market.Dr. Elizabeth Lee, of the Methodist Hospital Wound Care Center inArcadia, California, said the inexpensiveness of the bandage was animportant feature."Most of our patients are elderly, and cost is a big issue to them,"she said.Dr. Timothy Shea of the John Muir Wound Care Center in Concord,California, said the bandages could play an important role in thetreatment non-healing wounds, but that they are not a magic cure-all."By itself it would not be enough," he said. "It would have to beused in combination with other wound-care treatments," such as woundcleansing and infection control.The team developing the smart bandage has yet to test its product ona human patient. However, Edwards said that test tube experimentshave had positive results.Clinical trials will begin this year, he said. If those trials aresuccessful, the process of manufacturing the bandages could begin ina year.