Bone tissue engineering based on bead–cell sheets composed of calcium phosphate beads and bone marrow cells

We developed a new tissue-engineered bone graft model composed of bovine bone marrow stromal cells (BMSCs), and beta tricalcium phosphate (beta TCP) porous beads. Such cell–bead sheets were prepared by means of cultivation of BMSCs with the beads in alpha-MEM culture medium supplemented with 10% fetal bovine serum. The shape of the sheets was possible to change depending on that of a plastic mold having a circle or quadrangle shape. Addition of poundage on the overlaid cell–bead sheets induced the connection of these sheets with each other, and achievement of thicker implant formation. A nonwoven fabric sheet of poly-l-lactic acid (PLLA) could also be inserted in between each cell–bead sheet. Consequently, bone implants having a size of 20×20×5 mm were successfully developed. This kind of techniques would be useful in thick implants for other tissue implants.