Apatite-forming ability and antibacterial property of Ag-CaO-SiO₂/polyetherether ketone composites

Ceramic biomaterials have been used to recover the lost functions of the damaged bones by direct fusion with the bones. CaO-SiO₂system has been known as a bioactive material that has an ability to form apatite on the surface of the bones inside the body fluid. Applications of biomaterials could require the use of excess amount of antibiotics during transplantation to prevent any infections or microbism. Ag ion has been known for its unique biological properties of antibiosis. We already reported that CaO-SiO₂gels prepared by a sol-gel method can be used as inorganic fillers for osteoconductive composites because they showed apatite-forming ability in a simulated body fluid. In this study, we synthesized 30CaO70SiO₂(CS) gel powders modified with Ag ions ranging from 0 to 100 ppm to provide antibacterial property. Using the Ag-modified CS powders, composites were prepared by combining with polyetheretherketone (PEEK), which was used as a polymer matrix. Apatite formation in a simulated body fluid was observed on all the composites regardless of Ag contents. The composites consisting of CS modified with Ag ions suppressed multiplication of E.coli. Consequently, CS/PEEK modified with Ag ions not only retained its ability of forming HAp but also gained an antibacterial property.