Enhanced anti-microbial activity and osseointegration of Ta/Cu co-implanted polyetheretherketone

Abstract

Polyetheretherketone (PEEK) has been widely applied for orthopedic and oral implants due to its excellent mechanical properties, biocompatibility, and radiolucency. However, its bioinert and the lack of anti-microbial activity limit its application. We modified the PEEK surface with Ta/Cu co-implantation using plasma immersion ion-implantation technology. After implantation of Ta/Cu ions, the morphology and roughness of the PEEK surface were not significantly changed at micron level. We estimated the cytocompatibility, anti-microbial ability, and osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs) of the modified surfaces in vitro. Compared to the untreated surfaces, the Ta ion-treated surface showed improved adhesion, proliferation, ALP activity, ECM mineralization, and osteogenic gene expression of BMSCs. Further, the Cu ion-treated surface showed reduced initial adhesion and proliferation of Escherichia coli and Staphylococcus aureus in vitro and proliferation of Staphylococcus aureus in the mouse subcutaneous implant-associated infection model. According to a rat bone repair model, all Ta ion-implanted groups demonstrated improved new bone formation. In summary, Ta/Cu ion co-impanation improved anti-microbial activity and promoted osseointegration of the PEEK surface.

Keywords: Copper; Ion implantation; Osseointegration; Polyetheretherketone; Tantalum.