Pattern-coated titanium bone fixation plate for dual delivery of vancomycin and alendronate

Abstract

Metallic bone-fixation devices have been widely used in the treatment of fractured bones. However, there are still some unmet clinical needs associated with post-surgical infection and hampered bone repair. Therefore, to both prevent infection and enhance bone formation, we propose a titanium (Ti)-based bone plate for dual delivery of an antibiotic, vancomycin (VAN), and a bone-forming drug, alendronate (AL). In this work, we prepared the coating with a blend of a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), and a drug, VAN or AL. Instead of coating the whole surface, we patterned the coatings each in the shape of a dot, on a flat surface of the Ti bone plate currently in clinical use (BP0001-PT, U&I, Korea). This way, we could prevent detachment of the polymeric coating from the metallic plate surface while being immersed in an aqueous medium for 23 days. Both VAN and AL were released in a sustained manner for more than 28 days, maintaining their own activity without being influenced by their co-existence in the medium. Thus, the coated plate showed an antibacterial activity against Staphylococcus aureus, while also promoting osteoblast proliferation and alkaline phosphate activity in MG-63 cells. Therefore, we conclude that a Ti-based bone plate coated with patterned dots, each for delivery of VAN or AL, can be a promising strategy to allow for both antibacterial and bone-forming activities.