Simultaneous engineering of nanofillers and patterned surface macropores of graphene/hydroxyapatite/polyetheretherketone ternary composites for potential bone implants

Highlights: • Dual nanoparticles of graphene oxide (GO) and hydroxyapatite (HAp) were added to PEEK. • Patterned macropores were created on ternary GO/HAp/PEEK composite surface. • 400 μm macropores promote more cell adhesion and proliferation over other macropores. • Dual strategies of adding nanofillers and creating pores show synergistic effects. Incorporating bioactive nanofillers and creating porous surfaces are two common strategies used to improve the tissue integration of polyetheretherketone (PEEK) material. However, few studies have reported the combined use of both strategies to modify PEEK. Herein, for the first time, dual nanoparticles of graphene oxide (GO) and hydroxyapatite (HAp) were incorporated into PEEK matrix to obtain ternary composites that were laser machined to create macropores with diameters ranging from 200 μm to 600 μm on the surfaces. The surface morphology and chemistry, mechanical properties, and cellular responses of the composites were investigated. The results show that micropatterned pores with a depth of 50 μm were created on the surfaces of the composites, which do not significantly affect the mechanical properties of the resultant composites. More importantly, the incorporation of GO and HAp significantly improves the cell adhesion and proliferation on the surface of PEEK. Compared to the smooth surface composite, the composites with macroporous surface exhibit markedly enhanced cell viability. The combined use of nanofillers and surface macropores may be a promising way of improving tissue integration of PEEK for bone implants.