Bacteriostatic Polylactic Acid Coatings Enriched with Zinc Oxide and Silica Nanoparticles for Titanium Pedicle Screws

Pedicle screws have been dip coated with polylactic acid (PLA) enriched with zinc oxide (ZnO) and silica (SiO2) nanoparticles (NPs) to provide antibacterial coatings as a preventive strategy against bacterial infections in spine surgery. ZnO NPs were synthesized as an antibacterial component and SiO2 NPs were further blended into the PLA + ZnO NPs composition to improve the biocompatibility of the coating. ZnO NPs as the sole component of PLA coatings on pedicle screws resulted in more than 90% reduction in the colony-forming units when immersed in bacterial cell suspension. Meanwhile, screws coated with PLA + ZnO + SiO2 could eliminate bacterial cell adhesion. The results confirm the dominance of ZnO NPs as an antibacterial component of the coating matrix compared with SiO2 NPs, while SiO2 could improve the biocompatibility of the coating enriched with ZnO NPs.