Development and characterization of printablePLA/β-TCPbioactive composites for bone tissue applications

In this study, poly(lactic acid) (PLA) and PLA/beta-tricalcium phosphate (TCP) biocomposites were developed by melt compounding using an internal melt mixer with three different TCP contents (5, 10, and 25 wt%). A comprehensive analysis of the thermal, rheological, and mechanical properties of these biocomposites was performed. TCP presented proper distribution in the PLA/TCP biocomposites: PLA5TCP and PLA10TCP exhibited rheological behavior similar to that of neat PLA. However, PLA25TCP presented significant agglomeration and reduction in thermal stability. Addition of TCP to the biocomposites enhanced their bioactivity and biocompatibility. The bioactivity assay was conducted by immersing the samples in SBF solution for 7 and 21 days, and the SEM and XRD surface analyses of the PLA/TCP biocomposites presented evidence of carbonated hydroxyapatite formation. The biocompatibility assay was performed using the extract method until 7 days, and PLA10TCP presented improved relative cell viability compared with the control. Finally, since the materials presented suitable thermal and rheological properties, filaments for additive manufacturing (AM) were developed, and they were used to produce screw models for bone-ligament fixation. The 3D printed screws exhibited excellent printability and accuracy. Therefore, the PLA/TCP biocomposites developed can be used in further biomedical applications using AM, namely, guided bone tissue engineering.