Osteogenic differentiation of bone marrow mesenchymal stem cells on the collagen/silk fibroin bi-template-induced biomimetic bone substitutes.

Biomimetic bone substitutes of collagen-silk fibroin/hydroxyapatite (COL-SF/HA) were synthesized via a bi-template-induced coassembly strategy. Collagen-hydroxyapatite (COL-HA) and silk fibroin-hydroxyapatite (SF-HA) served as controls were prepared with similar method. The osteogenic differentiation ability of bone marrow mesenchymal stem cells (BMSCs) seeded onto the resulting materials was evaluated both in vitro and in vivo. The results suggested that the bi-template-induced biomimetic substitutes were able to support the growth and proliferation of BMSCs. We further demonstrated that BMSCs were stimulated to differentiate into the osteoblast cell lineage by evaluating several specific osteogenic markers including staining of alkaline phosphate (ALP) and calcium nodular and expression of osteogenic genes of osteocalcin (OCN) and osteonectin (ONN). The rat femoral defect model was used to assess the aforementioned biomimetic bone substitutes combined with BMSCs in vivo. Histological analysis indicated that the bi-template material exhibited good biocompatibility and strong ability of the new bone formation in comparison with the control of single-template material in vivo.