The team created compounds known as aminosilane-based sol-gels as thin films on glass slides. They then converted the amino acid groups to nitric oxide donors by exposing the films to high pressures of nitric oxide gas.
Later measurements showed that the compounds released nitric oxide gas continuously for days, Schoenfisch said. Varying the amount and type of aminosilane in the sol-gel could change the rate and amount of nitric oxide release.
To test whether the materials prevented bacterial adhesion, the team then exposed both nitric oxide-releasing and untreated control slides to solutions of Pseudomonas aeruginosa, a common infection-causing bacterium. Bacterial adhesion was as much as 70 percent lower on the nitric oxide-releasing slides.
Preventing bacterial adhesion and biofilm formation is vital for reducing infection since biofilms are extremely resistant to immune system defenses once they have formed on an implant, the scientist said. Such films can cause chronic illness with severe and universal symptoms such as headache, nausea, vomiting, abdominal cramps, sore throat, sore eyes and fever, making diagnosis difficult.
Besides its anti-bacterial adhesion properties, nitric oxide plays a role in several other important physiological processes including blood pressure regulation, nerve transmission, platelet adhesion and tumor cell growth. The impotence drug Viagra relies on nitric oxide action to work, he said.
People in the biomaterial research community have been struggling for years to control bacterial adhesion, Schoenfisch said. Despite the many recent advances in medicine, implant-related infection remains a most serious problem. Polymeric nitric oxide release represents a unique strategy, particularly since nitric oxide has a short half-life in blood -- just a few seconds -- and thus would only have an effect on areas near the implant site where
Contact: David Williamson
University of North Carolina at Chapel Hill