Support of silk fibroin/hydroxyapatite scaffold on the proliferation and differentiation of bone marrow mesenchymal stem cells: Superior to collagen sponge?

BACKGROUND: Conventional hydroxyapatite is limited because of its low strength, small porosity, and poor osteoconduction. A novel scaffold, mixed silk fibroin with hydroxyapatite (SF/HA), might be a promising choice. OBJECTIVE: To observe the effects of SF/HA scaffold on biocompatibility with the bone marrow mesenchymal stem cells (BMSCs), and to compare with common collagen sponge. DESIGN, TIME AND SETTING: The study of repetitive measurement and multiple sample observation was performed at the laboratory of the Department of Orthopaedics, First Affiliated Hospital, Soochow University from January 2007 to June 2008. MATERIALS: SF/HA scaffold was supplied by Professor Li Ming-zhong, from the College of Material, Soochow University. Collagen sponge was purchased from Shanghai Qisheng. METHODS: Rat BMSCs were harvested from the femur and tibia, and then subcultured. BMSCs at the third passage were incubated on the both SF/HA and collagen sponge scaffold in vitro. Cells were cultured without scaffold as blank control group. MAIN OUTCOME MEASURES: The morphologic function of the BMSCs was observed by inverted microscope. The proliferation of the BMSCs on the scaffold and alkaline phosphatase (ALP) activity were measured by MTT assay at days 2, 4, 6 and 8. RESULTS: The BMSCs adhered, proliferated and grew perfectly on the both scaffolds under the inverted microscope. The evaluations of cellular proliferation and ALP activity were not influenced by the scaffolds. They were increased with culture time, and greater than control group. CONCLUSION: The SF/HA scaffold has good biocompatibility, can promote cell growth and differentiation, and can be a good supplement and substitute for collagen tissue engineering scaffold.