A team of University of British Columbia scientists believes it has found a way to harness the anti-bacterial powers of silver without harming the patients it is used on.
Silver has long been researched as a way to keep implanted medical devices – catheters, feeding tubes, stents – free from bacteria, but no one has been able to successfully pull it off. Too much of the metal can be toxic, and coatings made from it have been overly complicated, lacked durability, become gummed up, or haven’t adhered well to surfaces, according to a news release from UBC.
The UBC team’s silver-based coating appears to circumvent these issues, though. A combination of silver nitrate, dopamine and two hydrophilic polymers, the coating slowly releases silver ions in controlled quantities. It repels live and dead bacteria from the implanted medical devices, but doesn’t harm human cells.
The research team has run two successful tests with it. In a 30-day trial, which placed a medical device in an environment with high concentrations of diverse and resilient bacteria, the device came away bacteria free. The coating performed just as well in a seven-day trial with live rats, according to the team.
Co-senior author Dirk Lange said other silver-based coatings rely on bacteria to actually land on the device before they can be killed.
“This results in dead bacteria building up on the surface over time and rendering the device ineffective,” he said.
Their coating, by comparison, slowly releases the silver and kills the bacteria before it ever touches the medical devices. This is how it’s able to last 30 days bacteria free.
The team says use of their coating could be relatively cheap too. They estimate it would cost 50 cents to add it to a catheter.
If their work passes clinical trials, the coating could be in use and preventing infections within the next decade.