Raimondi M T, Boschetti F, Falcone L, Fiore G B, Remuzzi A, Marinoni E, Marazzi M, Pietrabissa R
Department of Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133 Milan, Italy.
Biomech Model Mechanobiol. 2002 Jun;1(1):69-82. doi: 10.1007/s10237-002-0007-y.
Natural cartilage remodels both in vivo and in vitro in response to mechanical forces and hence mechanical stimulation is believed to have a potential as a tool to modulate extra-cellular matrix synthesis in tissue-engineered cartilage. Fluid-induced shear is known to enhance chondrogenesis on animal cells. A well-defined hydrodynamic environment is required to study the biochemical response to shear of three-dimensional engineered cell systems. We have developed a perfused-column bioreactor in which the culture medium flows through chondrocyte-seeded porous scaffolds, together with a computational fluid-dynamic model of the flow through the constructs' microstructure. A preliminary experiment of human chondrocyte growth under static versus dynamic conditions is described. The median shear stress imposed on the cells in the bioreactor culture, as predicted by the CFD model, is 3 x 10(-3) Pa (0.03 dyn/cm(2)) at a flow rate of 0.5 ml/min corresponding to an inlet fluid velocity of 44.2 mum/s. Providing a fluid-dynamic environment to the cells yielded significant differences in cell morphology and in construct structure.
天然软骨在体内和体外都会对机械力作出反应而发生重塑，因此，机械刺激被认为有潜力作为一种调节组织工程软骨中细胞外基质合成的工具。已知流体诱导的剪切力可增强动物细胞的软骨形成。研究三维工程细胞系统对剪切力的生化反应需要一个明确的流体动力学环境。我们开发了一种灌注柱生物反应器，其中培养基流经接种有软骨细胞的多孔支架，同时还建立了一个通过构建体微观结构的流动的计算流体动力学模型。描述了在静态和动态条件下人类软骨细胞生长的初步实验。根据计算流体动力学模型预测，在生物反应器培养中施加在细胞上的平均剪切应力在流速为0.5 ml/min（对应入口流体速度为44.2 μm/s）时为3×10⁻³ Pa（0.03 dyn/cm²）。为细胞提供流体动力学环境会导致细胞形态和构建体结构出现显著差异。
