Development and Biomechanical Tests of Poly-L-Lactide Bone Screws with CT Imaging Enhancment and 3D Printing Bifunction

Polylactic acid (PLA)-based composites were used as bone/tissue regeneration materials for many years. Recently, how to modify the physical, chemical and biological properties of the PLA-based materials for improving its medical application has become an issue for biomaterial sciences. It has been reported that iron oxide magnetic nanoparticles exhibit not only biocompatibility, but also biohave effect on the osteoblastic proliferation. Accordingly, the aim of this study is to develop a novel nano-magnetic bioresorbable bone screw by using both injection molding and 3D printing techniques. For methodology, nanoscale magnetite will be incorporated into the PLA matrix with various nano-Fe3O4/PLA mixing ratios. Pure PLA samples will be carried out as a blank control. Thermodynamic, mechanical, and biocompatibility will be tested to confirm the performance of this composite. Then nano-Fe3O4/PLA bone screws will be fabricated by injection molding and 3D printing techniques. The mechanical properties of these bone screw will be tested by simulated model in vitro. In addition, Animal studies will be performed to test the healing status between nano-Fe3O4/PLA screw and bone tissue. The CT imaging enhancement of the nano-Fe3O4/PLA bone screw will be evaluated. Accordingly, after finishing this study, we will provide a novel magnetic bioresorbable screw which will be applied in future orthopaedic treatment.