Porous Collagen-Hydroxyapatite Scaffolds With Mesenchymal Stem Cells for Bone Regeneration
Current bone grafting materials have significant limitations for repairing maxillofacial and dentoalveolar bone deficiencies. An ideal bone tissue-engineering construct is still lacking. The purpose of the present study was first to synthesize and develop a collagen-hydroxyapatite (Col-HA) composite through controlled in situ mineralization on type I collagen fibrils with nanometer-sized apatite crystals, and then evaluate their biologic properties by culturing with mouse and human mesenchymal stem cells (MSCs). We synthesized Col-HA scaffolds with different Col:HA ratios. Mouse C3H10T1/2 MSCs and human periodontal ligament stem cells (hPDSCs) were cultured with scaffolds for cell proliferation and biocompatibility assays. We found that the porous Col-HA composites have good biocompatibility and biomimetic properties. The Col-HA composites with ratios 80:20 and 50:50 composites supported the attachments and proliferations of mouse MSCs and hPDSCs. These findings indicate that Col-HA composite complexes have strong potentials for bone tissue regeneration.

Macroscopic and scanning electron microscopy views of the prototype collagen-hydroxyapatite (Col-HA) composites. (a) Pure type I collagen without HA. (b) 80%Col-20%HA composite. (c) 50%Col-50%HA composite. (d) 20%Col-80%HA composite.

Prototype collagen-hydroxyapatite (Col-HA) composites support the attachments and proliferations of GFP tagged mesenchymal stem cells (C3H10T1/2 + Adi-GFP) for 1, 3, 5, and 7days (fluorescence microscopy ×50). (a) 80%Col-20%HA. (b) 50%Col-50%HA. (c) 20%Col-80%HA. (d) Pure type I collagen (Collaplug).

The results of cytotoxicity assays in vitro: the living human periodontal ligament stem cell (hPDSC) numbers were counted by a hemacytometer under a light microscope at 1, 3, and 6 days. The proliferation of hPDSCs (cell number × 105) on CPL (CollaPlug), FD (Foundation), collagen (a prototype collagen without HA), and hydroxyapatite (HA50) (50%Col-50%HA composite) (P > .05, ANOVA).
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