Study on Hollow Hydroxyapatite Microspheres as Delivery System for Human Bone Morphogenetic Protein

Hollow hydroxyapatite microspheres consisted of a hollow core and a porous shell were prepared by converting Li2O―CaO―B2O3 glass microspheres in dilute phosphate solution at 37 . Human bone morphogenetic protein (rhBMP―2) was loaded in the resultant microspheres, and the in vitro release behavior of rhBMP―2 was studied. Furthermore, cell culture technique and ALP kit were used to investigate the effect of the released rhBMP―2 on cell activity. After incubation with rhBMP―2 loaded microspheres, the alkaline phosphatase (ALP) activity of the rat bone marrow mesenchymal stem cells (MSCs) was evaluated. It was found that rhBMP―2 could be released slowly from the hollow HA microspheres for an extended period time up to 1000h. The present delivery system established possessed higher biological activity as compared with pure rhBMP―2.