3D printed scaffolds for tissue engineering applications: Mechanical, morphological, thermal, in-vitro and in-vivo investigations

Abstract Thermoplastic composites of polylactic acid (PLA)-hydroxyapatite (HAp)-chitosan (CS) (in 91-8-1% weight proportion) is one of the acceptable composition/proportions for preparation of biomedical scaffolds (printed by fused deposition modeling (FDM)) in tissue engineering applications. But hitherto, little has been reported on the repair of PLA-HAp-CS based orthopedic scaffolds, especially in case of minor surface cracks observed post-surgery (maybe because of residual stresses/accident, etc.) from mechanical, thermal, in-vitro, in-vivo, and morphological analysis viewpoint. In this study, the 3D printed scaffolding structures of PLA-HAp-CS (3D printed on FDM) were further joined by friction stir spot welding (FSSW) process for minor repairs (such as surface cracks). The joints formed by the FSSW process were subjected to mechanical, thermal, cytotoxicity (by in-vitro, in-vivo analysis) and morphological analysis. The study results suggest that joints prepared using the consumable tool in FSSW have good mechanical, thermal stability, a good range of biocompatibility, and suitable tissue engineering applications. For FSSW of 3D printed scaffolding structures of PLA-HAp-CS, 1000 rpm tool rotational speed, 4 mm consumable plunge depth, and 40 s stirring time are the optimized set of process parameters. The results are also supported by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis.