Silver wound dressing

A new kind of wound dressing uses silver in a way that kills bacteria but does not damage cells needed for healing.

The dressing, developed by Ankit Agarwal, a postdoctoral researcher at the University of Wisconsin-Madison, is made with an ultra-thin material carrying a precise dose of silver.

One square inch contains just 0.4 per cent of the silver that is found in the silver-treated antibacterial bandages now used in medicine.

The amount of silver used in these current wound dressings, Agarwal said, has been shown to kill cells known as fibroblasts that are needed to repair a wound.

In tests, the low concentration of silver killed 99.9999 per cent of the bacteria but did not damage fibroblasts.

Agarwal built the material from polyelectrolyte multilayers - a sandwich of ultra-thin polymers that adhere through electrical attraction. To make the sandwich, Agarwal alternately dipped a glass plate in two solutions of oppositely charged polymers. Finally, he added a precise dose of silver.