Cell distribution in a scaffold with random architectures under the influence of fluid dynamics

Fluid dynamic environment and scaffold architectures have an important influence on cell growth and distribution inside the scaffold. A porous cylindrical scaffold with a central channel is seeded with the sheep mesenchymal stem cells (MSCs) in this study. Then the cell seeded scaffold is continuously perfused with alpha-MEM medium by a peristaltic pump for 7, 14, and 28 days. Histological study shows that the cell proliferation rates are different throughout the whole scaffolds. The different cell coverage is shown in various positions of the scaffold. A computational fluid dynamics (CFD) modeling is used to simulate the flow conditions within perfused cell-seeded scaffolds to give insight into the mechanisms of these cell growth phenomena. Relating the simulation results to perfusion experiments, the even fluid velocity (approximately 0.26-0.64 mm/s) and shear stress (approximately 0.0029-0.027 Pa) are found to correspond to increased cell proliferation within the cell-scaffold constructs. This method exhibits novel capabilities to compare results obtained for different perfusion rates or different scaffold microarchitectures and may allow specific fluid velocities and shear stresses to be determined that optimize the perfusion flow rate, porous scaffold architecture, and distribution of in vitro tissue growth.