PCL/HA Hybrid Microspheres for Effective Osteogenic Differentiation and Bone Regeneration

The purpose of this study is to develop a bioactive bone graft based on polycaprolactone (PCL, synthetic polymer; used in clinical practices as a grafting material for craniofacial bone defects) and hyaluronic acid (HA, bioactive natural polymer; known as a promoting substance for bone regeneration) that would be fabricated by clinically available procedures (mild condition without toxic chemicals) and provide bioactivity for sufficient period, and thus effectively induce bone reconstruction. For this, PCL/HA hybrid microspheres were produced by a spray-precipitation technique using clinically adapted solvents. The HA was stably and evenly entrapped in the PCL/HA hybrid microspheres. It was demonstrated that the PCL/HA hybrid microspheres provide an appropriate environment for proliferation and osteogenic differentiation of human periosteum-derived cells (hPDCs) (in vitro) and allow significantly enhanced bone regeneration (in vivo) compared with PCL microspheres without HA. The PCL/HA hybrid microspheres can be a simple but clinically applicable bioactive bone graft for large-sized bone defects.