Immunological mechanism of Sr/Cu ion synergistically promote implant osseointegration

Controlled immune response, enhanced osteogenesis, and antibacterial effect are essential for successful implanted biomaterials in the long-term. However, the previous research only considers one of the above-mentioned materials’ properties, and the potential synergetic effects are still unknown. Inspired by the mussel adhesion-mediated ions-coordinated strategy, a multifunctional coating integrated with bioactive Sr²⁺ and antibacterial Cu²⁺ was fabricated the multifunctional PEEK implants (PEEK-PDA-Sr/Cu). Compared to the uncoating PEEK, the PEEK implants with a multifunctional coating can regulate the M1 subtypes of macrophages to M2 subtypes due to the presence of Sr²⁺, which further promote the osteogenic differentiation of BMSCs. Even under the bacterial infection environment, the PEEK implants with a multifunctional coating can still enhance the osseointegration of bone implants due to the antibacterial properties of Cu²⁺. Taken together, PEEK implants with a multifunctional coating can provide an osteogenic immune microenvironment with enhanced osteogenesis and antibacterial property, which is essential for successful implantation in the long-term.