Osteogenic differentiation of bone marrow stem cells using thermo-sensitive hydrogels

Poly(ethylene glycol)-based diblock and triblock thermo-sensitive polyester copolymers were investigated for application on tissue engineering and injectable biomaterials in drug delivery system due to their nontoxicity, biocompatibility and biodegradability. We synthesized the diblock copolymers consisting of methoxy poly(ethylene glycol) (MPEG) (Mn=750 g/mole) and poly(ε-caprolactone) (PCL) by ring opening polymerization of ε-CL with MPEG as an initiator in the presence of HCl · Et₂O. The effect of diblock copolymers on in vivo osteogenic differentiation of rat bone marrow stromal cells (BMSCs) with and without the presence of osteogenic supplements (dexamethasone) was investigated. Thin sections were cut from paraffin embedded tissues and histological sections were stained by H&E, von Kossa, and immunohistochemical staining for osteocalcin. In conclusion, dexamethasone containing thermo-sensitive hydrogel might be improved osteogenic differentiation of BMSCs. We expect the osteoinduction effect to be excellent when it uses stem cell or other osteogenic materials.