Development of a bone reconstruction technique using a solid free-form fabrication (SFF)-based drug releasing scaffold and adipose-derived stem cells.

For tissue regeneration, three essential components of scaffolds, signals (biomolecules), and cells are required. Moreover, because bony defects are three-dimensional in many clinical circumstances, an exact 3D scaffold is important. Therefore, we proposed an effective reconstruction tool for cranial defects using human adipose-derived stem cells (hADSCs) and a 3D functional scaffold fabricated by solid free-form fabrication (SFF) technology that secretes biomolecules. We fabricated poly(propylene fumarate)-based 3D scaffolds with embedded microsphere-deliverable bone morphogenetic protein-2 (BMP-2) by microstereolithography. BMP-2-loaded SFF scaffolds with/without hADSCs (SFF/BMP/hADSCs scaffolds and SFF/BMP scaffolds, respectively) and BMP-2-unloaded SFF scaffolds (SFF scaffolds) were then implanted in rat crania, and in vivo bone formation was observed. Analyses of bone formation areas using micro-computed tomography (micro-CT) showed the superiority of SFF/BMP/hADSCs scaffolds. Hematoxylin and eosin stain, Masson's trichrome stain, and collagen type-I stain supported the results of the micro-CT scan. And human leukocyte antigen-ABC showed that seeded, differentiated hADSCs were well grown and changed to the bone tissue at the inside of the scaffold. Results showed that our combination of a functional 3D scaffold and hADSCs may be a useful tool for improving the reconstruction quality of severe bony defects in which thick bone is required.