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Analysis of shear stress due to shaking culture vessels or agitation of medium in plant cell culture

植物细胞培养中摇动培养容器或搅拌培养基引起的剪切应力分析

基本信息

批准号：
03452275
负责人：
KURATA Kenji
金额：
$ 4.42万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

项目摘要

The objectives of the study were to analyze the physical stress imposed on cells or cell aggregates in liquid culture caused by agitaion or aeration for supplying oxygen to cells or for mixing the medium. The adopted methods of analysis were to visualize the medium movement and to analyze it. The selected culture vessels for analysis were flasks for shake culture and bioreactors.The tracer method was adopted for visualization method, in which we utilized nylon particles for tracers. By photographing the trajectories of the nylon particles during a short period, the liquid movement was visualized. When data on streamline direction were also needed, light was emitted by a stroboscope to mark the beginning and end of the streamlines. The obtained images of streamlines were analyzed by a computer and distribution of streamlines, rotation and shear stress in the flow field were calculated. These flow characteristics were selected as ones relevant to hydrostatic stresses to the cells.In the case of the flask shake culture, a laser light sheet (laser light spread in thin plane) was used to visualize the liquid movement in a horizontal plane at the middle of the liquid. The results showed a flow pattern which consisted of high velocity region, moderate velocity region, and low velocity region. The pattern itself rotated in accordance with the flask rotation. The patterns were dependent on the rotation speed. With the increase of the rotation speed, the averages of the absolute values of rotation and shear stress increased. Unlike the case of shake culture, liquid movement in a bioreactor was fully three-dimensional, and we need two images taken simultaneously from two angles, In this case, identifying the same particle in the two images were requested. We are making efforts to overcome this difficulty.

本研究的目的是分析在液体培养中，由于向细胞供氧或混合培养基而引起的搅拌或通气对细胞或细胞聚集体施加的物理应力。采用的分析方法是观察培养基的运动并进行分析，分析所用的培养容器为摇瓶和生物反应器，观察方法采用示踪法，其中示踪剂为尼龙颗粒。通过在短时间内拍摄尼龙颗粒的轨迹，使液体运动可视化。当还需要关于流线方向的数据时，由频闪仪发出的光标记流线的开始和结束。利用计算机对所获得的流线图像进行分析，计算了流场中的流线、旋转和切应力的分布。在摇瓶培养的情况下，使用激光片（激光在薄平面中传播）来观察液体在液体中间的水平面中的运动。结果表明，该流型由高速区、中速区和低速区组成。模型本身根据烧瓶旋转而旋转。这些图案取决于旋转速度。随着旋转速度的增加，旋转和剪切应力的绝对值的平均值增加。与振荡培养的情况不同，生物反应器中的液体运动是完全三维的，并且我们需要从两个角度同时拍摄两张图像，在这种情况下，要求在两张图像中识别相同的颗粒。我们正在努力克服这一困难。