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.