Non-stick coating keeps bacteria off medical implants

Chuck Bednar for – Your Universe Online

Experts from Harvard University have developed a powerful new non-stick material that could help prevent infections by keeping bacteria from building up on medical implants.

Citing National Institutes of Health statistics, the researchers claim that over 80 percent of all human microbial infections are caused by bacteria that accumulate and form biofilms – adhesive colonies that help bacteria survive but threaten the health of their human hosts.

These biofilms typically form on medical surfaces, including mechanical heart valves, catheters and implants. In the inaugural edition of the journal ACS Biomaterials Science and Engineering, however, the Harvard scientists detail how they were able to develop a potent and long-lasting repellant surface technology that could prevent such infections.

According to Gizmodo, the new material uses polymers infused with naturally lubricating liquid. The polymer molecules soak up large amounts of these liquids, then slowly release the lubricant, making the surface of the medical material slippery enough that the biofilm is unable to form.

Lead investigator Joanna Aizenberg, a materials science professor at the Harvard School of Engineering and Applied Sciences (SEAS) as well as a professor of chemistry and chemical biology at the university, and her colleagues created the coating using solid silicone polymers (already commonly used in medical situations) that they infused with non-toxic silicon oil.

The silicone tubing is saturated with the oil, soaking so much of it up that the two materials essentially become one, noted co-author Caitlin Howell, a postdoctoral researcher at the Wyss Institute for Biologically Inspired Engineering. It is this process that the Harvard team says makes the polymer so powerful, and ultimately could result in a material capable of withstanding both conventional sterilization methods and long-term use.

The surface does not appear to become less slippery over time, they added. The silicone oil used in the experiments continuously replenishes itself in order to replace any oil that is lost due to its exposure to fluids such as blood or urine. During testing, the polymer proved effective against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus epidermidis – three bacteria that regularly form biofilms and cause infections.

“With widespread antibiotic resistance cropping up in many strains of infection-causing bacteria, developing out-of-the-box strategies to protect patients from bacterial biofilms has become a critical focus area for clinical researchers,” explained Donald Ingber, founding director of the Wyss Institute and a professor of vascular biology at Harvard Medical School.

The increasing antibiotic resistance of bacteria coupled with the difficulty of removing biofilms once they form could make their preventative aspects of the polymer invaluable, added Ingber, who is also a professor of bioengineering at Harvard SEAS. “Liquid-infused polymers could be used to prevent biofilms from ever taking hold, potentially reducing rates of infection and therefore reducing dependence on antibiotic use,” he noted.


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