3D-printing and characterization of PEEK bioactive composites for craniofacial applications

Abstract

This research investigated the 3D printing of PEEK bioactive nanocomposites with Strontium (Sr) and Zinc (Zn) doped hydroxyapatites. Doped hydroxyapatites were synthesized by wet chemical precipitation method and incorporated into polyetheretherketone (PEEK) up to 30 wt.% and processed by a novel approach i.e., fused filament fabrication (FFF) 3D printing for the production of patient specific cranial implants with improved bioactivity and the required mechanical performance. PEEK nanocomposite filaments were produced via extrusion and subsequently 3D-printed using FFF. In order to further improve the bioactivity of the 3D-printed parts, the samples were dip-coated in polyethylene glycol-DOPA (PEG1000-DOPA) solution. The printing quality was influenced by filler loading but was not significantly influenced by the nature of doped-HA. Hence, the printing conditions were optimized for each sample. Micro-CT and Scanning Electron Microscopy (SEM) showed a uniform distribution of bioceramic particles in PEEK. Although agglomeration of particles increased with increase in filler loadings. Differential Scanning Calorimetry (DSC) showed that the melting point and crystallinity of PEEK increased with an increase in doped-HA loading from 343 °C to 355 °C and 27.7% to 34.6%, respectively. Apatite layer formation was analyzed on the surfaces of 3D-printed samples after immersion in simulated body fluid (SBF) for 7, 14 and 28 days via SEM, X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The tensile strength and impact strength decreased from 75.1 MPa to 51 MPa and 14 kJ/m2 to 4 kJ/m2, respectively, while Young’s modulus increased with increasing doped-HA content from 2.8 GPa to 4.2 GPa. However, the tensile strengths of composites remained in the range of human cortical bone i.e., ≥50 MPa. In addition, the mechanical strengths of the samples after 28 days immersion in SBF were measured. Water contact angle showed that the hydrophilicity of the samples improved after coating the 3D-printed samples with PEG1000-DOPA. Hence, based on the results, the 3D-printed PEEK nanocomposites with 20 wt.% doped-HA is selected as the best candidate for the 3D-printing of craniomaxillofacial implants.

Date of Award	Oct 2022
Original language	English
Sponsors	INTERREG VA
Supervisor	Elena Mancuso (Supervisor), Atefeh Golbang (Supervisor) & Dorian Dixon (Supervisor)