3D printed phosphate glass/polylactide composites for orthopaedic application

Phosphate glass/polylactic acid composites have shown great potential as orthopaedic implant materials due to excellent biocompatibility, biodegradability and bone-mimicking mechanical properties. However, the moulding-based fabrication process and poor post-processing ability of composites pose a problem for manufacturing implants with the desired size and shape for proper anatomical fit and consequent effective healing. In this study, the phosphate glass/polylactide composites were additively manufactured via fused deposition modelling (FDM). The incorporation of 10 wt.% phosphate glass particles (PGP) /milled fibres (PGF) improved the stiffness of implants by ~14% but led to 5% of strength reduction. The trend was intensified to ~30% modulus increment and ~8% strength reduction when 20 wt.% PGP was incorporated. By incorporating 10 wt.% of PGF in composites, the strength reduction was almost the same, whereas the improvement of flexural modulus of ~30% was significantly higher than that of PGP incorporation. Moreover, it was found that the PGF reinforced composites maintained around 70% of their initial mechanical p roperties even after 56 days of degradation in phosphate buffered saline. These properties allow PGF 10 composites for the fixation of low load-bearing bone structures. More importantly, the use of FDM method allows PGF reinforced composites with desired geometrical features to be built, which are potential for patient-specific biomedical implants.