In 3D tissue engineering, scaffold has very important role in holding 3D structure, cell adhesion, cell differentiation and mechanical property. Previous studies show that mesenchymal stem cells differentiate smooth muscle cells or vascular endothelial cells by mechanical stress. Other studies show that the microstructure of cell adhesion surface influence to the stem cell differentiation. We set up the hypothesis that 3D scaffold with microstructure and mechanical stress can control the cell differentiation. Poly L-lactic acid (PLLA) is biodegradable polymer widely used as scaffold. In our research, two types of PLLA scaffold with microstructure is used. Porous scaffolds are made by mixing PLLA and NH_4HCO_3. Fibrous scaffolds are made by using electrospinning method, which makes polymer nanofiber. SEM images of scaffold show that pore size of porous scaffold is about 50〜100um and that of fibrous scaffold is about 5〜10um. Seeding hMSCs on porous/fibrous 3D scaffold and culture 3 days in the dynamic culture devise. After cell culture, the differentiation rate is analyzed by PCR. Results of PCR show that fibered structure inhibits the differentiation to endothelial cells and that the dynamic culture promotes the differentiation to smooth muscle cells. These results show a part of the relation between microstructure and cell differentiation. For blood vessel regeneration, further study about microstructure and mechanical stress is need.
