Evaluation of hybrid porous biomimetic nano-hydroxyapatite/polyamide 6 and bone marrow-derived stem cell construct in repair of calvarial critical size defect.

Nano-hydroxyapatite/polyamide 6 (n-HA/PA6) composite scaffolds were prepared by a combined method of phase separation and particle leaching processing technique. The porous matrices were seeded with allogenic bone marrow-derived stem cells (BMSCs) and implanted in the critical-size calvarial defect (8-mm diameter) in rats. The adhesion, proliferation, and differentiation of BMSCs were demonstrated by (3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazoliumbromide) assay, immunohistochemical staining, and scanning electron microscopy in vitro. Cell survival was tracked via fluorescent labeling in vivo. The regeneration process was evaluated by several techniques at 4, 8, and 16 weeks after implantation. According to the results, the porous n-HA/PA6 scaffolds are biocompatible and have no negative effects on the BMSCs in vitro. Nano-hydroxyapatite/polyamide 6 composite combined with BMSCs exhibited good biocompatibility and osteoconductivity and enhanced osteogenesis at the initial stage after implantation. The results demonstrated that porous n-HA/PA6 scaffold is a potential matrix for bone tissue engineering, and using BMSCs as seed cells on porous n-HA/PA6 might be an alternative procedure in repair of large defect due to enhanced osteogenesis and osteointegration.