[Tissue engineered bone regeneration of periosteal cells using recombinant human bone morphogenetic protein 2 induce]

To investigate bone regeneration of the cell-biomaterial complex using strategies of tissue engineering based on cells.

Hydroxyapatite/collagen (HAC) sandwich composite was produced to mimic the natural extracellular matrix of bone, with type I collagen serving as a template for apatite formation. A three-dimensional poly-porous scaffold was developed by mixing HAC with poly(L-lactic acid) (PLA) using a thermally induced phase separation technique (TIPS). The rabbit periosteal cells were treated with 500 ng/ml of recombinant human bone morphogenetic protein 2 (rhBMP-2), followed by seeded into pre-wet HAC-PLA scaffolds. Eighteen 3-month nude mice were implanted subcutaneously cell suspension (group A, n = 6), simple HAC-PLA scaffold (group B, n = 6) and cell-biomaterial complex (group C, n = 6) respectively.

Using type I collagen to template mineralization of calcium and phosphate in solution, we get HAC sandwich composite, mimicking the natural bone both in composition and microstructure. The three dimensional HAC-PLA scaffold synthesized by TIPS had high porosity up to 90%, with pore size ranging from 50 microm to 300 microm. SEM examination proved that the scaffold supported the adhesion and proliferation of the periosteal cells. Histology results showed new bone formation 8 weeks after implantation in group C. The surface of group A was smooth without neoplasma. Fibrous tissue invasion occurred in group B and no bone and cartilage formations were observed.

The constructed tissue engineering bone has emerged as another promising alternative for bone repair.