Sponge-inspired sulfonated polyetheretherketone loaded with polydopamine-protected osthole nanoparticles and berberine enhances osteogenic activity and prevents implant-related infections

Infection and loosening of implants after joint replacement are the complications that have troubled patients and doctors for a long time. To prevent such complications, we selected polyether ether ketone (PEEK) used in orthopedic implants and endowed it with antibacterial and osteogenic activities via surface modification. First, we made a spongy three-dimensional structure on the surface of PEEK via sulfonation reaction and then embedded osthole nanoparticles with osteogenic activity. In the process of material preparation, we creatively found that polydopamine (PDA) can protect the morphology of osthole nanoparticles. Then, we applied a silk fibroin–berberine coating with antibacterial function to the surface of the material. The covalent adsorption of silk fibroin on berberine realized rapid and sustained release of berberine from the material. In vitro experiments confirmed that (Ost + Ber)@SPEEK (sulfonated PEEK loaded with osthole particles and berberine) can promote osteogenesis by upregulating the expression of osteogenesis-related genes. Additionally, (Ost + Ber)@SPEEK prevents bacterial adhesion and has a killing effect on the suspended bacteria around it. The intrafemoral implant experiment in rats has confirmed that (Ost + Ber)@SPEEK can promote osteogenesis and prevent endophytic infection in vivo. This study presented a new strategy to fabricate biofunctionalized PEEK-based implants for potential applications in orthopedics field.