Application of Degradable Porous Scaffold for Bone Regeneration

Bone defects caused by trauma and disease present severe threat to human health. At present, allografts and autografts are the most utilized methods to repair bone defects. However, these treatments have inherent shortcomings such as high failure rates due to poor graft fixation/tissue integration, potential disease transmission and limited supplies, as well as additional surgical hurt. Synthetic bone grafts, if properly engineered with physical properties enabling stable graft fixation, robust osteoconductive and osteoinductive properties encouraging new bone growth, and safe degradation, could help address these challenges.<br/> We report here degradable scaffolds based on poly(lactic acid) derivatives modified with poly(ethylene glycol), which exhibit high-efficiency shape recovery around body temperature and hydration induced stiffening and swelling effects. Composites of these polymers mixed with nanosized hydroxyapatite were electrospun to fabricate meshes composed of nano/micro fibers with size range from 150 nm to 10 μm. With the help of hydroxyapatite, the morphology of electrospun meshes improved wherein bulk nodules in the fibers reduced and nano/micro fibers become more smooth. As the content of hydroxyapatite increased, the average size of nano/micro fibers decreased and mechanical strength of electrospun mesh lowered. These electrospun meshes showed to support the attachment, proliferation and osteogenesis of osteoprogenitor cells <i>in vitro</i>. However, mouse bone marrow stromal cells (BMSCs) cultured on electrospun meshes exhibited suppressed activity with high hydroxyapatite content of 30 wt% indicated by CCK-8 result. Gene expressions of RUNX2, ALPL, COL1A1 and OCN increased at 14th day shown with q-PCR data, demonstrated potential osteogenic differentiation.