Bimetallic ions regulated PEEK of bone implantation for antibacterial and osteogenic activities

After the surgical implantation of polyetheretherketone (PEEK) orthopedic biomaterials, there are two major clinical challenges, implantation-related pathogen infection and poor osseointegration-caused aseptic loosening, threaten the lifespan and the success of the implants. In this study, we developed PEEK implants with antibacterial and osteogenesis capabilities by the bimetallic ions immersion method. Specifically, we pre-treated the PEEK implants with polydopamine (PDA) and then immobilized it (PEEK-PDA) with Mn2+ and Cu 2+ to obtain the bimetallic ions-modified PEEK denoted as PEEK-PDA-Mn/Cu. The PEEK-PDA-Mn/Cu exhibited enhanced antibacterial capabilities in both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) compared with PEEK without the modification of Cu 2+. In addition, MC3T3-E1 cells showed better morphology and enhanced osteogenic differentiation with the treatment of PEEK-PDA-Mn/Cu than other PEEK implants. Furthermore, S. aureus-infected femur-defect Sprague-Dawley rat models were developed to evaluate the function of PEEK-PDA-Mn/Cu in vivo. After 2 and 4 weeks of implantations, rats treated with PEEK-PDA-Mn/Cu exhibited limited bacterial infections and enhanced new bone formation compared with the rats treated with other PEEK implants. Overall, the PEEK-PDA-Mn/Cu can inhibit bacterial infections and promote osteogenic differentiation both in vitro and in vivo, which could provide a promising PEEK candidate for clinical applications.