Researchers Create Promising Antifouling Film
February 27, 2007
People obviously don't expect to get sick from a stay in the hospital. But hospital-acquired infections from tainted medical devices are relatively common, and many doctors say they have no good tools to prevent them. This terrible problem has led scientists to try and modify the surface chemistry of catheters and other indwelling medical devices, making them resistant to microbial colonization. In recent years, other promising scientific approaches have emerged. One of the most interesting is coating medical devices with a biocatalytic antifouling film. As the name suggests, scientists embed antimicrobial enzymes directly into the film’s composite polymer matrix to prevent microbial colonization. While the initial work has been promising, scientists have bumped into two technically challenging problems. The first is to incorporate into the matrix adequate levels of structurally unstable enzyme. The second is to ensure that the incorporated enzyme remains catalytically active under a range of operating conditions. In the January issue of the journal Small, a team of NIDCR grantees and colleagues may have found a solution through nanotechnology. According to the authors, they created single-walled carbon nanotubes that were “ideal supports” for subtilisin Carlsberg (CS), a much-studied enzyme that hydrolyzes, or breaks down, protein polymers. They incorporated the nanotube-CS conjugates within a poly(methyl methacrylate) polymer matrix. According to the authors, the nano-SC composite was 30 times more catalytically active than polymers containing graphite-SC conjugates. In addition, they found the nano-SC film to be highly stable, retaining more than 90 percent of its initial activity over 30 days in aqueous buffer. The film was also active in temperatures up to 70 degrees Celsius.