Novel PEEK/nHA composites fabricated by hot-pressing of 3D braided PEEK matrix

Integration of nanohydroxyapatite (nHA) into polyetheretherketone (PEEK) has been recognized as an effective approach to improve osseointegration of PEEK-based devices. In this work, we report a novel method based on 3D braiding-self retention-hot pressing to yield a bioactive PEEK/nHA composite with superior mechanical properties. The better apatite formation ability and higher MC3T3-E1 cell adhesion and proliferation for the braided PEEK composite reinforced with 6.5 wt% and 14.5 wt% nHA displayed than the unfilled PEEK matrix, mainly ascribed to the incorporation of nHA. Meanwhile, the elastic modulus, hardness, and bending strength of binary composites increased from 4.3 to 8.3 GPa, 0.23 to 0.34 GPa, and 138.86 to 155.32 MPa correspondingly. Compared with the fracture toughness of pure PEEK matrix, that of 6.5 wt% nHA/PEEK composites had a 54.9% increase, whereas that of 14.5 wt% nHA/PEEK composites showed a 23.6% decrease, which was mainly attributed to the interfacial properties between HA and PEEK as well as braid structure of PEEK filaments. These findings exhibited both good mechanical properties and bioactivity of the braided PEEK/nHA composites. Therefore, it is proposed that the 3D braiding-self retention-hot pressing technique is a promising approach for customized PEEK-based implants.Graphical abstract