Nanoparticles 'stamp out' bacteria

April 13, 2011

Researchers here have developed a way to cause an ultra-thin antibacterial coating to adhere to a wound, Medical News Today reports.

Madison, Wis. - Researchers here have developed a way to cause an ultra-thin antibacterial coating to adhere to a wound, Medical News Today reports.

In a study published in the journal Advanced Functional Materials, University of Wisconsin-Madison researchers describe a process for creating a transparent ultra-thin polymer coating carrying precise loads of extremely fine silver nanoparticles. In the experiment, investigators spread the ultra-thin coating onto a flexible piece of rubber and then stamped it onto a piece of cadaver skin that simulated a wound.

To test the activity against bacteria, researchers treated skin samples with two bacteria that commonly infect wounds. They then used a silver dosage they knew to be harmless to skin cells. No bacteria were detectable after 12 hours, investigators report.

Medical News Today quotes lead author Ankit Agarwal as saying that silver “has been used to prevent and treat infections for ages. But silver can also kill skin cells, and therefore we need to develop materials that deliver antibacterial but nontoxic levels of silver to wounds.”

The technology offers many benefits, researchers say. First, it places the silver nanoparticles directly in the wound, allowing nontoxic doses (up to 100 times lower than what is used in commercial silver dressings) to have antibacterial activity. Second, chemical engineers should be able to make a sustained-release version to reduce the need for repeated applications and dressing changes. Moreover, although bacteria can evolve to become resistant to antibiotics, they virtually never develop a resistance to silver.

The authors say the method is “applicable to a range of soft materials and could incorporate a variety of molecules onto the tissue surface that could influence fundamental cell behaviors involved in healing.”