Fenge C, Klein C, Heuer C, Siegel U, Fraune E
B. Braun Biotech International, Melsungen, Germany.
Cytotechnology. 1993;11(3):233-44. doi: 10.1007/BF00749874.
For an optimized bioreactor design which is adapted to the cultivation of sensitive animal cells different modular bioreactor components for gentle agitation, sufficient aeration and long-term perfusion were developed and investigated with respect to their suitability from laboratory to production scale. Aeration systems have been designed for both shear sensitive cells and cells which tolerate bubbles. The systems are based on either membranes for bubble-free aeration or stainless steel sparger systems. They were characterized by determination of their oxygen transfer capacity and optimized in cultivation processes of different cell lines under process conditions such as batch and perfusion mode. Different impellers for suspension cells and cells grown on carriers were investigated for their suitability to ensure homogeneous gentle mixing. A large pitch blade impeller as well as a novel 3-blade segment impeller are appropriate for homogeneous mixing at low shear rates. Especially with the 3-blade segment impeller fluid mechanical stress can be reduced at a given stirrer speed which is advantageous for the cultivation of cells attached to microcarriers or extremely shear sensitive suspension cells. However, our results indicate that shear sensitivity of animal cells has been generally overestimated. Continuous perfusion of both suspension cell cultures and cells cultivated on microcarriers could be successfully performed over extended periods of time using stainless steel spinfilters with appropriate pore sizes and systems based on microporous hydrophilic membranes. Spinfilters are suitable cell retention systems for technical scale bioreactors allowing continuous perfusion cultures of suspension cells (pore size 10 to 20 microns) as well as anchorage dependent cells grown on microcarriers (pore size 75 microns) over six weeks to 3 months. Applying the developed modules for agitation, aeration and perfusion process adapted bioreactor set-ups can be realized which ensure optimum growth and product formation conditions in order to maximize cell and product yields.
为了设计出一种优化的生物反应器，使其适用于敏感动物细胞的培养，开发并研究了不同的模块化生物反应器组件，这些组件用于温和搅拌、充足曝气和长期灌注，并考察了它们从实验室规模到生产规模的适用性。针对对剪切敏感的细胞和耐受气泡的细胞，设计了曝气系统。这些系统基于无泡曝气的膜或不锈钢气体分布器系统。通过测定其氧传递能力对它们进行了表征，并在分批和灌注模式等工艺条件下，在不同细胞系的培养过程中对其进行了优化。研究了用于悬浮细胞和在载体上生长的细胞的不同搅拌桨，以确定它们确保均匀温和混合的适用性。大螺距叶片搅拌桨以及新型三叶分段搅拌桨适用于低剪切速率下的均匀混合。特别是使用三叶分段搅拌桨时，在给定搅拌速度下可降低流体机械应力，这有利于培养附着在微载体上的细胞或对剪切极度敏感的悬浮细胞。然而，我们的结果表明，动物细胞的剪切敏感性通常被高估了。使用具有适当孔径的不锈钢旋转过滤器和基于微孔亲水膜的系统，可以成功地对悬浮细胞培养物和在微载体上培养的细胞进行长时间的连续灌注。旋转过滤器是适用于工业规模生物反应器的细胞截留系统，可实现悬浮细胞（孔径10至20微米）以及在微载体上生长的贴壁依赖性细胞（孔径75微米）长达六周至三个月的连续灌注培养。应用所开发的用于搅拌、曝气和灌注的模块，可以实现适合工艺的生物反应器设置，从而确保最佳的生长和产物形成条件，以最大化细胞和产物产量。
