Enhanced osteogenic and antibacterial properties of polyetheretherketone by ultraviolet‐initiated grafting polymerization of a gelatin methacryloyl/epsilon‐poly‐L‐lysine/laponite hydrogel coating

Abstract

AbstractPolyetheretherketone (PEEK) is a promising material for use in orthopedic implants, but its bio‐inert character and lack of antibacterial activity limit its applications in bone repair. In the present study, considering the advantages of PEEK in self‐initiated graft polymerization and of hydrogels in bone tissue engineering, we constructed a hydrogel coating (GPL) consisting of Gelatin methacryloyl (GelMA), methacrylamide‐modified ε‐poly‐l‐lysine (ε‐PLMA) and Laponite on PEEK through UV‐initiated crosslinking. The coating improved the hydrophilicity of PEEK, and the coating degraded slowly so that approximately 80% was retained after incubation in PBS for 8 weeks. In vitro studies revealed that as compared to culturing on PEEK, culturing on PEEK‐GPL led to enhanced viability and adhesion of cultured human umbilical cord Wharton's jelly‐derived mesenchymal stem cells (hWJ‐MSCs). Due to the synergistic effect of the micron‐scale three‐dimensional surface and Laponite, PEEK‐GPL exhibited a significantly improved induction of osteogenic differentiation of hWJ‐MSCs compared to PEEK, as demonstrated by increased alkaline phosphatase activity, matrix mineralization, and expression of osteogenesis‐related genes. Furthermore, PEEK‐GPL showed antibacterial activity upon contact with Staphylococcus aureus and Escherichia coli, and this activity would be maintained before complete degradation of the hydrogel because the ε‐PLMA was cross‐linked covalently into the coating. Thus, PEEK‐GPL achieved both osteogenesis and infection prevention in a single simple step, providing a feasible approach for the extensive use of PEEK in bone implants.