Novel cell seeding system into a porous scaffold using a modified low-pressure method to enhance cell seeding efficiency and bone formation.

The efficient seeding of cells into porous scaffolds is important in bone tissue engineering techniques. To enhance efficiency, we modified the previously reported cell seeding techniques using low-pressure conditions. In this study, the effects of low pressure on bone marrow-derived stromal cells (BMSCs) of rats and the usefulness of the modified technique were assessed. There was no significant difference found in the proliferative and osteogenic capabilities among various low-pressure (50-760 mmHg, 1-10 min) conditions. To analyze the efficacies of the cell seeding techniques, BMSCs suspended in the plasma of rats were seeded into porous beta-tricalcium phosphate (beta-TCP) blocks by the following three procedures: 1) spontaneous penetration of cell suspension under atmospheric pressure (SP); 2) spontaneous penetration and subsequent low pressure treatment (SPSL), the conventional technique; and 3) spontaneous penetration under low pressure conditions (SPUL), the modified technique. Subsequently, these BMSCs/beta-TCP composites were used for the analysis of cell seeding efficiency or in vivo bone formation capability. Both the number of BMSCs seeded into beta-TCP blocks and the amount of bone formation of the SPUL group were significantly higher than those of the other groups. The SPUL method with a simple technique permits high cell seeding efficiency and is useful for bone tissue engineering using BMSCs and porous scaffolds.