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 es- tablished possessed higher biological activity as compared with pure rhBMP-2.