The Effect of Porous Sr-Containing Hydroxyapatite on Bone Marrow Mesenchymal Stem Cells and Osteogenesis

Hydroxyapatite bioceramics as a kind of bone defect repair and replacement material has been in clinical application for years. In order to further clarify the role of the addition of Sr on the physicochemical properties of these materials, a series of Sr-substituted hydroxyapatites (Sr-HA) were synthesized by high temperature solid state methods and characterized extensively. The proliferation and osteogenesis reactivity of these materials in BMSCs was evaluated, and the behavior towards MG-63 osteoblast cells (in terms of cytotoxicity, proliferation and differentiation assays) was studied. Our results indicated that the addition of Sr does influence the structure of HA, and the crystallinity degree of the materials decreased with Sr addition. The increasing amounts of Sr in the HA composition causes a decrease in the specific surface area and an enrichment of Sr-apatite phase at the surface of the samples. Bioactivity tests show that the presence of Sr did not produce any cytotoxic effect. Moreover, Sr-HA increased the proliferation of BMSCs and MG-63 osteoblast cells and enhanced BMSCs differentiation to osteoblast cells. Thus the Sr-HA is an optimal scaffold material for bone tissue engineering, which can be potentially applied in clinical practice for bone defect repair by compounding with osteoblasts.