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

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 prop-erty (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 signifi-cantly activated the response (adhesion, proliferation, alkaline phosphatase activity and expressions of osteo-genic 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 cel-lular response. FPKH with pre-eminent cytocompatibility and bioactivity would have great potential for bone replacement. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study improved the bioactivity of PEEK by utilizing femtosecond laser technology and hydroxylation treatment to create micro-submicro structure and graft hydroxyl group on PEEK surface. The modified PEEK showed elevated surface properties and significantly activated the response of rat bone marrow stromal cells, indicating great potential for bone replacement.