Preparation and Biological Properties of HA Containing Astragalus Polysaccharides

Hydroxyapatite (HA) powders containing different concentrations of astragalus polysaccharides (APS) were synthesized by a wet chemical method. The effect of APS on the crystal structure, crystallinity and crystal size of HA was characterized by XRD, the crystal morphologies of HA and HA/APS were characterized by TEM, the particle size and specific surface area of HA were detected by laser partical size distribution analyzer, automated surface area and pore size analyzer, respectively. Furthermore, the effective concentration of APS on MC3T3-E1 osteoblasts, HA/APS on osteoblastic activity and differentiation was evaluated by Alamar blue, MIT and alkaline phosphatase assay. Cell morphologe was observed by light microscope. The results showed that the crystal structure, crystallinity and crystal size of HA were not obviously effected by the presence of APS. Crystal morphologies of HA/APS was almost the same compared with HA, the average particle size of HA was 1.17 mu m and specific surface area was 132.194 m(2)/g. The effect of APS on osteoblasts was time and dose-dependent, APS concentrations within 80-200 mu g/mL enhanced osteoblastic activity and ALP expression, HA/APS enhanced osteoblastic activity and the osteoblasts had integrated morphology. It can be concluded that 0.5 g of HA containing 100-250 mu m APS can promote osteoblastic activity. HA/APS has the promising potential as bone defect filling material for clinical applications.