Bioprocess Development, Sanofi, Framingham, Massachusetts.
Biotechnol Bioeng. 2019 Feb;116(2):320-332. doi: 10.1002/bit.26811. Epub 2018 Dec 1.
In this study, we investigated the effects of alternating tangential flow (ATF) cell separation on high-density perfusion cultures. We have developed methods to estimate theoretical residence times of cells in the ATF system and discovered that long residence times (above 75 s) correlate with decreased growth, metabolism, and productivity. We have calculated energy dissipation rates in the ATF transfer line and filter and empirically studied the impacts of increased exchange rates on cell culture, determining that increased hydrodynamic stress can lead to decreased cell size, lactate production, and specific productivity. Finally, we have conducted experiments to understand the relationship between filtration fluxes and ATF membrane fouling, finding that at fluxes above 60 L·m ·day , protein sieving coefficients see significant rates of decrease (greater than 1% per day). While most of these studies have been conducted with one cell line at one target viable cell density (40 million cells/ml), the general, directional knowledge arising from this study should be applicable to other conditions and programs, ultimately leading to more robust and well-designed perfusion processes.
在这项研究中，我们研究了交替切向流（ATF）细胞分离对高密度灌注培养的影响。我们已经开发了方法来估计细胞在 ATF 系统中的理论停留时间，并发现停留时间长（超过 75 秒）与生长、代谢和生产力下降相关。我们计算了 ATF 输送线和过滤器中的能量耗散率，并通过经验研究了增加交换率对细胞培养的影响，确定增加流体动力应力会导致细胞体积减小、乳酸生成和比生产力降低。最后，我们进行了实验以了解过滤通量与 ATF 膜污染之间的关系，发现通量高于 60 L·m·day -1 时，蛋白质筛分系数会出现显著的下降（每天超过 1%）。虽然这些研究大多数都是在一条细胞系和一个目标活细胞密度（4000 万细胞/ml）下进行的，但从这项研究中得出的一般方向性知识应该适用于其他条件和方案，最终导致更稳健和设计良好的灌注工艺。
