Cruel Magali, Bensidhoum Morad, Nouguier-Lehon Cécile, Dessombz Olivier, Becquart Pierre, Petite Hervé, Hoc Thierry
1 Laboratoire de Tribologie et Dynamique des Systèmes (LTDS, UMR CNRS 5513) , Ecole Centrale de Lyon, Ecully Cedex, France .
2 Laboratory of Bioengineering and Biomechanics for Bone and Articulations (B2OA, UMR CNRS 7052), University of Paris 7 , PRES Paris Cité, Paris, France .
Tissue Eng Part C Methods. 2015 Sep;21(9):863-71. doi: 10.1089/ten.TEC.2014.0648. Epub 2015 Apr 6.
Controlling the mechanical environment in bioreactors represents a key element in the reactors' optimization. Positive effects of fluid flow in three-dimensional bioreactors have been observed, but local stresses at cell scale remain unknown. These effects led to the development of numerical tools to assess the micromechanical environment of cells in bioreactors. Recently, new possible scaffold geometry has emerged: granular packings. In the present study, the primary goal was to compare the efficiency of such a scaffold to the other ones from literature in terms of wall shear stress levels and distributions. To that aim, three different types of granular packings were generated through discrete element method, and computational fluid dynamics was used to simulate the flow within these packings. Shear stress levels and distributions were determined. A linear relationship between shear stress and inlet velocity was observed, and its slope was similar to published data. The distributions of normalized stress were independent of the inlet velocity and were highly comparable to those of widely used porous scaffolds. Granular packings present similar features to more classical porous scaffolds and have the advantage of being easy to manipulate and seed. The methods of this work are generalizable to the study of other granular packing configurations.
控制生物反应器中的力学环境是反应器优化的关键要素。已观察到三维生物反应器中流体流动的积极作用，但细胞尺度的局部应力仍不明确。这些效应促使开发数值工具来评估生物反应器中细胞的微观力学环境。最近，出现了新的可能的支架几何结构：颗粒堆积。在本研究中，主要目标是在壁面剪应力水平和分布方面，将这种支架与文献中的其他支架的效率进行比较。为此，通过离散元法生成了三种不同类型的颗粒堆积，并使用计算流体动力学来模拟这些堆积内部的流动。确定了剪应力水平和分布。观察到剪应力与入口速度之间存在线性关系，其斜率与已发表的数据相似。归一化应力的分布与入口速度无关，并且与广泛使用的多孔支架的分布高度可比。颗粒堆积与更传统的多孔支架具有相似的特征，并且具有易于操作和接种的优点。这项工作的方法可推广到其他颗粒堆积构型的研究。
