Polydopamine coating for anchoring icariin-regulated CF/PEEK with enhanced cytocompatibility and osteogenic activity

Bioactivity is an important factor to be considered for orthopedic implants as it determines the success of the implant. Polyetheretherketone (PEEK), an orthopedic biomaterial, has been widely used in biomedical engineering. However, unsatisfactory bioactivity continues to plague the clinical application of PEEK. In this study, icariin (Ica) coating was prepared on carbon fiber-reinforced PEEK (CF/PEEK) surfaces by constructing an assistant platform of polydopamine (PDA) aimed at enhancing the bioactivity and osteogenic capacity. The physicochemical properties of the fabricated CF/PEEK were further explored, along with its morphology, release, wettability and mechanical properties. The CF/PEEK surface with an Ica coating accelerated the proliferation of BMSC cells obviously and exhibited good biocompatibility, suggesting that it has favorable biosafety in vitro. In addition, the osteogenic properties of the Ica coating were demonstrated by the upregulated expression of osteogenesis-associated genes, alkaline phosphatase and mineralization in vitro. Furthermore, in vivo, the CF/PEEK implants coated with the Ica coating promoted the osseointegration at the implant-bone interface compared with the CF/PEEK without Ica modification, and there was no significant inflammatory response for each implantation group. Our research provides a promising modification strategy for loading Ica on the PDA-assistant platform-modified CF/PEEK implants with cytocompatibility, non-immunogenicity, and osteogenic properties, which broaden the clinical modification application of TCM monomers for orthopedic implants.