Creating micro-submicro structure and grafting hydroxyl group on PEEK by femtosecond laser and hydroxylation to synergistically activate cellular response

Abstract Polyetheretherketone (PEEK) exhibits good biocompatibility and mechanical property but bioinert that does not activate the cellular response and stimulate bone regeneration. In the present study, to improve of bioactivity of PEEK, femtosecond laser technology was utilized to induce submicro structure on PEEK surface (FPK), which was subsequently treated by hydroxylation to create micro-submicro structure and simultaneously graft hydroxyl (-OH) group on FPK (FPKH). Compared with PEEK, FPK with submicro structure exhibited elevated surface property (roughness, hydrophilicity, surface energy and protein absorption). Moreover, FPKH with micro-submicro structure and -OH group further enhanced the surface property. In addition, compared with PEEK, FPK significantly activated the response (adhesion, proliferation, alkaline phosphatase activity and expressions of osteogenic genes) of rat bone marrow stromal cells (BMSC) in vitro. Furthermore, compared with FPK, FPKH further enhanced the cellular response, which were the synergistic effects of micro-submicro structure and -OH group. In short, combination of femtosecond laser and hydroxylation treatment created micro-submicro structure and grafted functional group of -OH on PEEK with elevated surface property, which played key roles in activating cellular response. FPKH with pre-eminent cytocompatibility and bioactivity would have great potential for bone replacement.