They are used especially to kill bacteria

Aug 20, 2009 00:41 GMT  ·  By
Precisely targeted silver molecules can kill almost all bacteria in a wound, but spare the essential fibroblast repair cells
   Precisely targeted silver molecules can kill almost all bacteria in a wound, but spare the essential fibroblast repair cells

Silver-treated antibacterial bandages are nothing new in hospitals around the world, but, while the chemical indeed kills most of the pathogens, it also harms certain cells in the patients' skins, which are necessary in order for the healing process to go as fast as possible. This happens on account of the large load of silver that remains in existing bandages, and researchers have been looking for a way to eliminate that for a long time. Now, one has apparently managed to achieve this.

University of Wisconsin-Madison (UWM) postdoctoral researcher Ankit Agarwal presented the new idea at the 238th annual meeting of the American Chemical Society on August 19th, in Washington DC. He says that the new material, which is extremely lightweight and contains only 0.4 percent of the amount of silver that can be found on regular, one-inch bandages, has the ability to kill about 99.99 percent of the bacteria it encounters, while leaving the essential fibroblast cells intact.

Fibroblasts are a crucial part of the body's response to injuries and burns, and they operate very quickly so as to limit the overall amount of damage that the body has to suffer from. By not inhibiting them, the new types of wound dressings could find particularly suited applications in treating injuries in diabetics, who notoriously suffer from poor blood flow. In many cases, injuries suffered by these people on their extremities require amputations, and doctors are looking at eliminating this “option.”

The new materials are constructed from several layers of ultra-thin polymers, which remain stuck to each other through their electrical interactions. These polyelectrolyte multilayers are made by alternately dipping a glass plate in solutions containing polymers of opposite electrical charges, and then injecting a precise dose of silver into the overall mix. “This architecture is very easily tuned to different applications,” Agarwal reveals, quoted by e! Science News.

“A commercial dressing needs to have a large quantity of silver so it can diffuse to the wound bed, and that quantity turns out to be toxic to mammalian cells in lab dishes. We are putting the silver where we need it, so we can use a small loading of silver, which does not exhibit toxicity to mammalian cells because the silver is precisely targeted,” UWM Professor of Chemical and Biological Engineering Nicholas Abbott, who advised Agarwal on his research, says.