Healing Wounds: Interactive dressing speeds the process

New, easily prepared materials promote more rapid healing of wounds in laboratory animals than conventional dressings do, researchers report. The new films ultimately could quicken the recovery of burn victims and patients with skin ulcers and bedsores, the team asserts.

The films are in a class of materials known as hydrogels, which are networks of polymers that swell in water. These new hydrogels are made from complex sugars called glycosaminoglycans (GAGs) that are normally found in the protein-containing gel, or extracellular matrix, that surrounds animal cells.

To make each polymer network, Glenn D. Prestwich and his colleagues at the University of Utah in Salt Lake City mix a solution of a modified GAG with a solution of much shorter molecules that make the GAG molecules stick together. For one hydrogel, the researchers use a modified version of hyaluronan, a natural GAG that promotes wound healing. For the other, they used a modified version of a GAG called chondroitin sulfate, which until now had no known healing effect.

Prestwich and his coworkers tested these two hydrogel preparations on mice that had wounds extending through their skin. After the scientists covered a wound with one of the hydrogels, they bathed the material with saline and protected it with a conventional polymer dressing used, for example, when skin is removed for transplant to a burn site.

After 7 days, wounds treated with one of the two hydrogel materials were 33 percent more thoroughly healed than those covered with only the conventional dressing, the researchers report in the September Biomaterials. The new films slowly integrate themselves into a wound as it’s healing, says Utah team member Jane Shelby.

“The problem of wounds in the United States is really a silent epidemic,” comments Glenn Warden of the Shriner’s Burn Institute in Cincinnati. In particular, skin ulcers and pressure sores plague the nation’s elderly and diabetic populations.

These people and those with moderate burns might benefit from new dressings, he says.

Although other scientists have constructed hydrogels from GAGs, the new ones are easier to make, the Utah researchers claim. The team is now attempting to form their hydrogels at the wound site so that they better mold into its shape, says Prestwich. The group is also incorporating into their hydrogels growth factors that could further speed healing.

“This is another demonstration where we’re moving toward truly matrix-based materials for the healing of wounds — getting away from simple coverings,” comments Vincent Falanga of Roger Williams Medical Center in Providence, R.I.