Bilgen Bahar, Sucosky Philippe, Neitzel G Paul, Barabino Gilda A
Department of Chemical Engineering, 342 Snell Engineering Center Northeastern University, Boston, Massachusetts 02115, USA.
Biotechnol Bioeng. 2006 Dec 20;95(6):1009-22. doi: 10.1002/bit.20775.
Cartilage tissue engineering requires the use of bioreactors in order to enhance nutrient transport and to provide sufficient mechanical stimuli to promote extracellular matrix (ECM) synthesis by chondrocytes. The amount and quality of ECM components is a large determinant of the biochemical and mechanical properties of engineered cartilage constructs. Mechanical forces created by the hydrodynamic environment within the bioreactors are known to influence ECM synthesis. The present study characterizes the hydrodynamic environment within a novel wavy-walled bioreactor (WWB) used for the development of tissue-engineered cartilage. The geometry of this bioreactor provides a unique hydrodynamic environment for mammalian cell and tissue culture, and investigation of hydrodynamic effects on tissue growth and function. The flow field within the WWB was characterized using two-dimensional particle-image velocimetry (PIV). The flow in the WWB differed significantly from that in the traditional spinner flask both qualitatively and quantitatively, and was influenced by the positioning of constructs within the bioreactor. Measurements of velocity fields were used to estimate the mean-shear stress, Reynolds stress, and turbulent kinetic energy components in the vicinity of the constructs within the WWB. The mean-shear stress experienced by the tissue-engineered constructs in the WWB calculated using PIV measurements was in the range of 0-0.6 dynes/cm2. Quantification of the shear stress experienced by cartilage constructs, in this case through PIV, is essential for the development of tissue-growth models relating hydrodynamic parameters to tissue properties.
软骨组织工程需要使用生物反应器，以增强营养物质的传输，并提供足够的机械刺激，以促进软骨细胞合成细胞外基质（ECM）。ECM成分的数量和质量在很大程度上决定了工程化软骨构建体的生化和力学性能。已知生物反应器内流体动力环境产生的机械力会影响ECM的合成。本研究对一种用于组织工程软骨构建的新型波浪壁生物反应器（WWB）内的流体动力环境进行了表征。这种生物反应器的几何形状为哺乳动物细胞和组织培养提供了独特的流体动力环境，并用于研究流体动力对组织生长和功能的影响。使用二维粒子图像测速技术（PIV）对WWB内的流场进行了表征。WWB内的流动在定性和定量方面均与传统旋转瓶中的流动有显著差异，并且受到构建体在生物反应器内位置的影响。通过速度场测量来估计WWB内构建体附近的平均剪应力、雷诺应力和湍动能分量。使用PIV测量计算得出，组织工程构建体在WWB中所经历的平均剪应力范围为0-0.6达因/平方厘米。在这种情况下，通过PIV对软骨构建体所经历的剪应力进行量化，对于建立将流体动力参数与组织特性相关联的组织生长模型至关重要。
