Antibacterial Effects of Sodium Borate and Calcium Borate Based Polymeric Coatings for Orthopedic Implants

Introduction Implants used in orthopedic surgery can be colonized by bacteria that form biofilm layers complicating treatment. We aimed to determine titanium implants' antibacterial and biofilm-degrading properties when coated with sodium borate (NaB) and calcium borate (CaB) minerals. Methods We analyzed twenty-four different implants. Three implants were not coated, three were coated with only a carrier polymer (alginate), and eighteen were coated with either CaB or NaB at different concentrations. The implants were incubated with Staphylococcus aureus, and then the bacterial colonies were enumerated. Results The highest microbial load was observed on the implant coated with alginate (1000 colony-forming units [CFU]/mL). The implant without coating contained a microbial load of 420 CFU/mL. The microbial loads of the implants coated with 0.75 mg/mL CaB or 0.25, 0.5, and 0.75 mg/mL NaB (100, 200, 0, and 0 CFU/mL, respectively) were lower than that of the implant without coating. No biofilm formation was observed on implant surfaces coated with 0.5 mg/mL NaB, 0.75 mg/mL NaB, or 0.75 mg/mL CaB; biofilm formation was observed on the implant without coating and alginate-coated implants surfaces. Conclusion At high concentrations, borate minerals (NaB and CaB) have a potent antibacterial effect on colonization and biofilm formation on the implant surface. These elements may be used in implant coating in the future because of their potential antibacterial effects.