Osseointegration and biosafety of graphene oxide wrapped porous CF/PEEK composites as implantable materials: The role of surface structure and chemistry

Abstract

Objectives: To investigate the influence of surface microstructure and chemistry after modification on surface bioactivity and biosafety of carbon fibers reinforced PEEK (CF/PEEK) composites as implants.

Methods: CF/PEEK composites with different CF contents (0 wt%, 25 wt% and 40 wt%) were prepared by injection molding and treated by concentrated sulfuric acid. A porous network was produced on the surface by etching action. Subsequently, the sulfonated CF/PEEK composites were immersed in GO solution. Thus, GO wrinkles with abundant functional groups were wrapped outside the porous nanostructures on CF/PEEK composites. The cell responses in vitro (proliferation, alkaline phosphatase activity and cell mineralization), osseointegration in vivo (fluorochrome labeling, H&E staining and X-ray analysis) and biosafety were investigated.

Results: The pore size of porous layer on the surface of CF/PEEK composites was improved with the increase of CF content. Subsequently, a silk-like GO wrinkles on the surface were formed by GO modification. And the more CF content, the greater the degree of GO wrinkles. The results revealed that GO functional wrinkle up-regulated surface hydrophilicity. In vitro cell experiments showed that porous nanostructures and GO wrinkles dramatically promoted initial cell behaviors. Significantly, GO modified composites exhibited enhanced bioactivity and osseointegration in vivo. Fortunately, the GO wrapped porous CF/PEEK composites displayed biosafety.

Significance: The surface modification is effective and the modified composites showed great bioactivity. The GO wrapped porous CF/PEEK composites would hold great potential for implants.

Keywords: Bioactivity; Biosafety; CF/PEEK composites; GO modification; Osseointegration.