CHAPEL HILL To varying degrees, medical implants such as catheters, artificial organs and sensors placed under the skin are critical to curing illness or making life better for the infirm, but they also raise the risk of serious infection. More than half of all hospital-acquired infections have been linked to implanted medical devices.

Now studies conducted by University of North Carolina at Chapel Hill chemists show it should be possible to cut that risk significantly by a method that mimics the bodys own self-defense mechanisms.

Led by Dr. Mark H. Schoenfisch, assistant professor of chemistry, researchers have found they can store nitric oxide in sol-gel based materials that could be used to coat implants. Nitric oxide, a natural anti-bacterial agent, is slowly released by the coating when placed in watery environments such as blood or tissue and reduces bacterias tendency stick to the implants and form living films that lead to infection.

Efforts to reduce infections related to medical implants using conventional antibiotic treatments suffer from the widespread problem of emerging resistance from the most troublesome bacterial strains, Schoenfisch said. However, local nitric oxide release mimics our bodys own self-defense mechanisms against foreign cells.

During a process called phagocytosis, immune system cells engulf bacteria and release high levels of reactive molecules, including nitric oxide, to destroy these foreign cells, he said. Thus, we hypothesized that polymeric nitric oxide release might represent a new approach for reducing bacterial adhesion and possibly the incidence or severity of infection.

A report on the research will appear in the Journal of the American Chemical Society this fall, but was posted Sept. 6 on the societys Web site under ASAP Contents http://pubs.acs.org/journals/jacsat/index.html. Graduate student Brian J. Nablo and former
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Contact: David Williamson
david_williamson@unc.edu
919-962-8596
University of North Carolina at Chapel Hill
7-Sep-2001