A team of researchers has solved a common problem with implantable medical devices. These types of devices, including pacemakers and prosthetic joints, can make patients more vulnerable to bacterial infections. By using special antimicrobial nanofibers, the team was able to prevent infections in mice. The details are in a paper that was just published in the journal Proceedings of the National Academy of Sciences.
Implantable medical devices and prostheses are used to treat a variety of conditions but a major complication is the risk of infection. The surfaces of the devices, usually metallic, can become colonized with bacteria. This “biofilm”, a thin layer of microbes, can lead to dangerous infections. Many of these infections are difficult to treat and become chronic, requiring life-long treatment. Previously, researchers had tried using antibiotic beads or powder coatings during implantation. The antibiotics are released and used up quickly, however, and only one type of drug can typically be added to these local delivery options.
Researchers from Johns Hopkins University spent years developing a new technology to combat biofilm infections. They designed a special biodegradable nanofiber coating that can release multiple antibiotics at controlled rates. The coating goes over implantable medical devices in a thin layer and protects the device from biofilms.
The team used mice to test their new technology. They gave the mice knee joint replacements and one group received the nanofiber coating over the pins while the other group got antibiotic-free pins. The mice were then exposed to Staphylococcus aureus bacteria. After two weeks, the antibiotic-free mice had bacteria on the artificial joint and pins. The group that was given the nanofiber layer had no bacteria present, even in surrounding tissue.
Although the technology is still in the early developmental stages, the antibiotic-releasing nanofibers show promise for preventing bacterial infections after the implantation of artificial joints and other devices. Follow-up studies will be necessary to test the safety of the antibiotic coatings.
Ashbaugh et al. Polymeric nanofiber coating with tunable combinatorial antibiotic delivery prevents biofilm-associated infection in vivo. Proceedings of the National Academy of Sciences (2016).