| NS0 cell damage by high gas velocity sparging in protein-free and cholesterol-free cultures. | |
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MedLine Citation:
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PMID: 18814288 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Recent developments in high cell density and high productivity fed-batch animal cell cultures have placed a high demand on oxygenation and carbon dioxide removal in bioreactors. The high oxygen demand is often met by increasing agitation and sparging rates of air/O2 in the bioreactors. However, as we demonstrate in this study, an increase of gas sparging can result in cell damage at the sparger site due to high gas entrance velocities. Previous studies have showed that gas bubble breakup at the culture surface was primarily responsible for cell damage in sparged bioreactors. Such cell damage can be reduced by use of surfactants such as Pluronic F-68 in the culture. In our results, where NS0 cells were grown in a protein-free and cholesterol-free medium containing 0.5 g/L Pluronic F-68, high gas entrance velocity at the sparger site was observed as the second mechanism for cell damage. Experiments were performed in scaled-down spinners to model the effect of hydrodynamic force resulting from high gas velocities on antibody-producing NS0 cells. Cell growth and cell death were described by first-order kinetics. Cell death rate constant increased significantly from 0.04 to 0.18 day(-1) with increasing gas entrance velocity from 2.3 to 82.9 m/s at the sparger site. The critical gas entrance velocity for the NS0 cell line studied was found to be approximately 30 m/s; velocities greater than 30 m/s caused cell damage which resulted in reduced viability and consequently reduced antibody production. Observations from a second cholesterol-independent NS0 cell line confirmed the occurrence of cell damage due to high gas velocities. Increasing the concentration of Pluronic F-68 from 0.5 to 2 g/L had no additional protective effect on cell damage associated with high gas velocity at the sparger. The results of gas velocity analysis for cell damage have been applied in two case studies of large-scale antibody manufacturing. The first is a troubleshooting study for antibody production carried out in a 600 L bioreactor, and the second is the development of a gas sparger design for a large bioreactor scale (e.g., 10,000 L) for antibody manufacturing. |
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Authors:
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Ying Zhu; James V Cuenca; Weichang Zhou; Amit Varma |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Biotechnology and bioengineering Volume: 101 ISSN: 1097-0290 ISO Abbreviation: Biotechnol. Bioeng. Publication Date: 2008 Nov |
Date Detail:
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Created Date: 2008-09-30 Completed Date: 2008-11-18 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 7502021 Medline TA: Biotechnol Bioeng Country: United States |
Other Details:
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Languages: eng Pagination: 751-60 Citation Subset: IM |
Affiliation:
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Process Sciences and Engineering, PDL BioPharma, Inc., 1400 Seaport Blvd, Redwood City, California 94063, USA. ying.zhu@pdl.com |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Antibodies / metabolism Bioreactors* Cell Culture Techniques* Cell Line, Tumor Cell Physiological Phenomena* Cell Survival Cholesterol Culture Media, Serum-Free / chemistry Stress, Mechanical* |
| Chemical | |
Reg. No./Substance:
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0/Antibodies; 0/Culture Media, Serum-Free; 57-88-5/Cholesterol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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