• Self-initiated surface graft polymerization of poly(2-methacryloyloxyethyl phosphorylcholine) on PEEK and carbon fiber reinforced PEEK for orthopaedic and spinal applications

INTRODUCTION: Poly(ether-ether-ketone) (PEEK) is considered to be promising novel polymer biomaterial for orthopaedic and spinal applications, because PEEK exhibits excellent mechanical properties, chemical stability, non-magnetic nature, and compatible with reinforcing agents such as carbon fibers, as compared with polyethylene or metallic materials. However, since conventional PEEK cannot satisfy these requirements: e.g., wear resistance and biocompatibility for use as an artificial joint or intervertebral body fusion cage. Therefore, study on the PEEK as implants study has also been focused on lubricity and biocompatibility of the polymer, either as reinforcing agents, or as a surface modification. In this study, we have demonstrated the fabrication of highly hydrophilic and biocompatible nanometer-scale modified surface by photo-induced graft polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC). The new and safer polymerization system was found out, that is, “self-initiated surface graft polymerization.” We hypothesize that the cell-membrane-like surface obtained with surface modification of biocompatible poly(MPC) (PMPC) [1] exhibits excellent biocompatibility and hydrophilicity under physiological conditions. In addition, the self-initiated surface graft polymerization by the generation of semi-benzopinacol containing radicals of the benzophenone units in PEEK, which acts as a photo-initiator during the grafting polymerization. This polymerization system is conducted in the absence of photo-active low molecular compound and in aqueous medium; this is human friendly and excellent biocompatibility.