Researchers from the University of Michigan (U-M) have found that a common ingredient in sunscreen could be an effective antibacterial coating for medical implants such as pacemakers and replacement joints. Using a coating of zinc oxide nanopyramids can disrupt the growth of methicillin-resistant Staphylococcus aureus (MRSA), reducing the film on treated materials by over 95%!
As indicated in the news release, “If the nanoparticles are shaped like a pyramid with a hexagon-shaped base, they are very effective at preventing an enzyme called beta-galactosidase from breaking down lactose into the smaller sugars glucose and galactose, which the bacteria use for fuel.”
“Shape is important, both for the enzyme and for the nanoparticles. The enzyme needs to be able to twist in order to cut the lactose into the smaller sugars. Two amino acids, or protein building blocks, sit opposite one another across a groove in the enzyme. The lactose fits into the groove, and the amino acids come together to catalyze the breakup into glucose and galactose.”
“Although more studies need to be carried out, we believe that zinc oxide nanopyramids interfere with this twisting motion, ” said Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Chemical Engineering, whose group made the nanoparticles.
“The strong antibacterial activity against MRSA and other pathogens is an exciting finding, ” said Dr. Kotov. “We want to better understand the mechanisms of the antibacterial function to fine tune its inhibitory activity and to identify the structural similarities among enzymes that pyramidal nanoparticles can inhibit.”
Scott VanEpps, M.D., Ph.D., a clinical lecturer and research fellow in the U-M Medical School’s Department of Emergency Medicine, told OTW, “Professor Kotov was able to synthesize ZnO nanoparticles with very specific shapes that could inhibit enzymes just like enzyme inhibitors that occur in nature. It was well known that ZnO had some antimicrobial properties but in this form they were much more potent. The next step was to try to link this enzyme inhibition effect with the antibacterial effect. We were surprised that the shape-specific pattern of enzyme inhibition was identical to the shape-specific pattern of bacterial/biofilm growth inhibition.”
“The layer-by-layer coating method for these antimicrobial ZnO nanoparticles can be applied to almost any material including titanium and other biomaterials used in orthopedic surgery procedures.”
