Cytotoxicity and in vivo biosafety of the polylactide based bone composite materials

In this study, we investigated the in vitro cytotoxicity and in vivo biosafety of reinforced polylactide (PLA) composites with hyaluronic acid-chitosan (HACS) complex and β -tricalcium phosphate ( β -TCP) powder. The cytotoxicity of HACS/PLA (with β -TCP) composites was almost the same as that of neat PLA indicating that HACS/PLA (with β -TCP) composites did not have toxic effects. In in vivo biosafety tests using X-ray and micro-CT imaging, HACS/PLA (with β -TCP) composites did not show any fracture during 20 weeks of implantation in the tibia and femur of rabbits. The HACS/PLA (with β -TCP) composites did not induce severe inflammatory responses such as recruitment of macrophages around the implantation site, as assessed by H&E and immune staining of biopsy samples, for 6 weeks after insertion into SD rats. Addition of β -TCP powder to HACS/PLA composite enhanced bone induction and regeneration. The HACS/PLA composites prepared in the present study have potential maxillofacial and orthopedic applications.