Abstract Stirred suspension culture is becoming a popular method for expanding human pluripotent stem cells (hPSCs). While stirring generates adequate fluid motions to lift the cells and facilitates mass transfers (of nutrients, dissolved gases, and metabolic wastes), excessive stirring could impose hydrodynamic forces deleterious for the growth of the cells. In this study, computational fluid dynamics (CFD) simulations were performed to first investigate hydrodynamic characteristics of fluid flows in a spinner flask, a common stirred suspension culture vessel used in laboratories. Flow patterns and distributions of shear stresses and the Kolmogorov length scales at varying impeller speeds were obtained. Comparison of the Kolmogorov length scales and sizes of hPSC aggregates, measured in the authors’ previous experimental study, showed a strong correlation between the two. In addition to the spinner flask which generated complex and transient turbulent flows, this study investigated a newly developed rotary wall vessel that had been designed to produce laminar, circular Couette flows in order to control shear stress. CFD simulations revealed significantly more uniform and homogeneous flows compared to those in the spinner flask, suggesting that the rotary wall vessel is a suitable culture vessel to investigate roles of shear stress on hPSCs in suspension.

中文翻译：

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用于干细胞培养的旋转瓶和旋转壁容器内的流体动力学特性

摘要 搅拌悬浮培养正成为扩增人类多能干细胞 (hPSC) 的流行方法。虽然搅拌会产生足够的流体运动来提升细胞并促进质量转移（营养物质、溶解气体和代谢废物），但过度搅拌可能会施加对细胞生长有害的流体动力。在这项研究中，计算流体动力学 (CFD) 模拟首先用于研究旋转烧瓶中流体流动的流体动力学特性，旋转烧瓶是实验室中常用的搅拌悬浮培养容器。获得了在不同叶轮速度下的流动模式和剪切应力分布以及 Kolmogorov 长度尺度。在作者之前的实验研究中测量的 Kolmogorov 长度尺度和 hPSC 聚集体的大小的比较，表明两者之间存在很强的相关性。除了产生复杂和瞬态湍流的旋转烧瓶外，本研究还研究了一种新开发的旋转壁容器，该容器旨在产生层流、圆形库埃特流以控制剪切应力。CFD 模拟显示，与旋转瓶中的流动相比，流动更加均匀和均匀，这表明旋转壁容器是一种合适的培养容器，可以研究剪切应力对悬浮的 hPSC 的作用。