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Surowiec I, Scholz J. Capacitance sensors in cell-based bioprocesses: online monitoring of biomass and more. Curr Opin Biotechnol 2023; 83:102979. [PMID: 37619528 DOI: 10.1016/j.copbio.2023.102979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 07/10/2023] [Accepted: 07/10/2023] [Indexed: 08/26/2023]
Abstract
Biocapacitance measurement has emerged as a widely used technique for monitoring bioprocesses that involve living cells. Over time, hardware and software developments have enabled this method to move from food towards biopharma industries for improved characterisation, monitoring and control of the bioprocess, even in strictly regulated production environments. In alignment with the general trends in biopharma towards new modalities such as virus-based and cell-based therapies, biocapacitance measurement is entering this area and provides new opportunities for process development and control. Based on the recent progress, the authors strongly believe that even though biocapacitance measurement is a mature, established technology for online biomass monitoring, the nearest future will bring its new and exciting developments and applications that will enhance bioprocess understanding and bring new solutions for enhanced process understanding, monitoring and control.
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2
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Dekevic G, Tertel T, Tasto L, Schmidt D, Giebel B, Czermak P, Salzig D. A Bioreactor-Based Yellow Fever Virus-like Particle Production Process with Integrated Process Analytical Technology Based on Transient Transfection. Viruses 2023; 15:2013. [PMID: 37896790 PMCID: PMC10612092 DOI: 10.3390/v15102013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 10/29/2023] Open
Abstract
Yellow Fever (YF) is a severe disease that, while preventable through vaccination, lacks rapid intervention options for those already infected. There is an urgent need for passive immunization techniques using YF-virus-like particles (YF-VLPs). To address this, we successfully established a bioreactor-based production process for YF-VLPs, leveraging transient transfection and integrating Process Analytical Technology. A cornerstone of this approach was the optimization of plasmid DNA (pDNA) production to a yield of 11 mg/L using design of experiments. Glucose, NaCl, yeast extract, and a phosphate buffer showed significant influence on specific pDNA yield. The preliminary work for VLP-production in bioreactor showed adjustments to the HEK cell density, the polyplex formation duration, and medium exchanges effectively elevated transfection efficiencies. The additive Pluronic F-68 was neutral in its effects, and anti-clumping agents (ACA) adversely affected the transfection process. Finally, we established the stirred-tank bioreactor process with integrated dielectric spectroscopy, which gave real-time insight in relevant process steps, e.g., cell growth, polyplex uptake, and harvest time. We confirmed the presence and integrity of YF-VLP via Western blot, imaging flow cytometry measurement, and transmission electron microscopy. The YF-VLP production process can serve as a platform to produce VLPs as passive immunizing agents against other neglected tropical diseases.
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Affiliation(s)
- Gregor Dekevic
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany; (G.D.); (L.T.); (D.S.); (P.C.)
| | - Tobias Tertel
- Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Virchowstrasse 179, 45147 Essen, Germany; (T.T.); (B.G.)
| | - Lars Tasto
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany; (G.D.); (L.T.); (D.S.); (P.C.)
| | - Deborah Schmidt
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany; (G.D.); (L.T.); (D.S.); (P.C.)
| | - Bernd Giebel
- Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Virchowstrasse 179, 45147 Essen, Germany; (T.T.); (B.G.)
| | - Peter Czermak
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany; (G.D.); (L.T.); (D.S.); (P.C.)
- Faculty of Biology and Chemistry, University of Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Denise Salzig
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, 35390 Giessen, Germany; (G.D.); (L.T.); (D.S.); (P.C.)
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3
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Shohan S, Zeng Y, Chen X, Jin R, Shirwaiker R. Investigating dielectric spectroscopy and soft sensing for nondestructive quality assessment of engineered tissues. Biosens Bioelectron 2022; 216:114286. [DOI: 10.1016/j.bios.2022.114286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/29/2022] [Accepted: 04/11/2022] [Indexed: 11/02/2022]
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4
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Caso S, Aeby M, Jordan M, Guillot R, Bielser J. Effects of pyruvate on primary metabolism and product quality for a high‐density perfusion process. Biotechnol Bioeng 2022; 119:1053-1061. [DOI: 10.1002/bit.28033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 11/09/2022]
Affiliation(s)
- Stefania Caso
- Biotech Process Sciences, Merck KGaA Corsier‐sur‐Vevey Switzerland
| | - Mathieu Aeby
- Biotech Process Sciences, Merck KGaA Corsier‐sur‐Vevey Switzerland
| | - Martin Jordan
- Biotech Process Sciences, Merck KGaA Corsier‐sur‐Vevey Switzerland
| | - Raphael Guillot
- Biotech Process Sciences, Merck KGaA Corsier‐sur‐Vevey Switzerland
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Bielser JM, Kraus L, Burgos-Morales O, Broly H, Souquet J. Reduction of medium consumption in perfusion mammalian cell cultures using a perfusion rate equivalent concentrated nutrient feed. Biotechnol Prog 2020; 36:e3026. [PMID: 32415806 DOI: 10.1002/btpr.3026] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/30/2020] [Accepted: 05/12/2020] [Indexed: 12/15/2022]
Abstract
Media preparation for perfusion cell culture processes contributes significantly to operational costs and the footprint of continuous operations for therapeutic protein manufacturing. In this study, definitions are given for the use of a perfusion equivalent nutrient feed stream which, when used in combination with basal perfusion medium, supplements the culture with targeted compounds and increases the medium depth. Definitions to compare medium and feed depth are given in this article. Using a concentrated nutrient feed, a 1.8-fold medium consumption (MC) decrease and a 1.67-fold increase in volumetric productivity (PR) were achieved compared to the initial condition. Later, this strategy was used to push cell densities above 100 × 106 cells/ml while using a perfusion rate below 2 RV/day. In this example, MC was also decreased 1.8-fold compared to the initial condition, but due to the higher cell density, PR was increased 3.1-fold and to an average PR value of 1.36 g L-1 day-1 during a short stable phase, and versus 0.46 g L-1 day-1 in the initial condition. Overall, the performance improvements were aligned with the given definitions. This multiple feeding strategy can be applied to gain some flexibility during process development and also in a manufacturing set-up to enable better control on nutrient addition.
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Affiliation(s)
- Jean-Marc Bielser
- Biotech Process Sciences, Merck Biopharma, Corsier-sur-Vevey, Switzerland
| | - Leon Kraus
- Biotech Process Sciences, Merck Biopharma, Corsier-sur-Vevey, Switzerland
| | | | - Hervé Broly
- Biotech Process Sciences, Merck Biopharma, Corsier-sur-Vevey, Switzerland
| | - Jonathan Souquet
- Biotech Process Sciences, Merck Biopharma, Corsier-sur-Vevey, Switzerland
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Rafferty C, O'Mahony J, Rea R, Burgoyne B, Balss KM, Lyngberg O, O'Mahony-Hartnett C, Hill D, Schaefer E. Raman spectroscopic based chemometric models to support a dynamic capacitance based cell culture feeding strategy. Bioprocess Biosyst Eng 2020; 43:1415-1429. [PMID: 32303846 DOI: 10.1007/s00449-020-02336-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/17/2020] [Indexed: 01/01/2023]
Abstract
Multiple process analytical technology (PAT) tools are now being applied in tandem for cell culture. Research presented used two in-line probes, capacitance for a dynamic feeding strategy and Raman spectroscopy for real-time monitoring. Data collected from eight batches at the 15,000 L scale were used to develop process models. Raman spectroscopic data were modelled using Partial Least Squares (PLS) by two methods-(1) use of the full dataset and (2) split the dataset based on the capacitance feeding strategy. Root mean square error of prediction (RMSEP) for the first model method of capacitance was 1.54 pf/cm and the second modelling method was 1.40 pf/cm. The second Raman method demonstrated results within expected process limits for capacitance and a 0.01% difference in total nutrient feed compared to the capacitance probe. Additional variables modelled using Raman spectroscopy were viable cell density (VCD), viability, average cell diameter, and viable cell volume (VCV).
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Affiliation(s)
- Carl Rafferty
- Janssen Sciences Ireland UC, BioTherapeutic Development, Ringaskiddy, Cork, Ireland. .,Cork Institute of Technology, Biological Sciences, Cork, Ireland.
| | - Jim O'Mahony
- Cork Institute of Technology, Biological Sciences, Cork, Ireland
| | - Rosemary Rea
- Cork Institute of Technology, Biological Sciences, Cork, Ireland
| | - Barbara Burgoyne
- Janssen Sciences Ireland UC, Product Quality Management, Cork, Ireland
| | - Karin M Balss
- Janssen Supply Group, Advanced Technology Center of Excellence, Raritan, NJ, USA
| | - Olav Lyngberg
- Janssen Supply Group, Advanced Technology Center of Excellence, Raritan, NJ, USA
| | | | - Dan Hill
- Biogen, Global Process Analytics, Research Triangle Park, NC, USA
| | - Eugene Schaefer
- Janssen Research and Development Malvern, DPDS, BioTherapeutic Development, Malvern, PA, USA
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Metze S, Blioch S, Matuszczyk J, Greller G, Grimm C, Scholz J, Hoehse M. Multivariate data analysis of capacitance frequency scanning for online monitoring of viable cell concentrations in small-scale bioreactors. Anal Bioanal Chem 2019; 412:2089-2102. [PMID: 31608427 PMCID: PMC8285309 DOI: 10.1007/s00216-019-02096-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/12/2019] [Accepted: 08/27/2019] [Indexed: 12/30/2022]
Abstract
Viable cell concentration (VCC) is one of the most important process attributes during mammalian cell cultivations. Current state-of-the-art measurements of VCC comprise offline methods which do not allow for continuous process data. According to the FDA's process analytical technology initiative, process monitoring and control should be applied to gain process understanding and to ensure high product quality. In this work, the use of an inline capacitance probe to monitor online VCCs of a mammalian CHO cell culture process in small-scale bioreactors (250 mL) was investigated. Capacitance sensors using single frequency are increasingly common for biomass monitoring. However, the single-frequency signal corresponds to the cell polarization that represents the viable cell volume. Therefore single-frequency measurements are dependent on cell diameter changes. Measuring the capacitance across various frequencies (frequency scanning) can provide information about the VCC and cope with changing cell diameter. Applying multivariate data analysis on the frequency scanning data successfully enabled direct online monitoring of VCCs in this study. The multivariate model was trained with data from 5 standard cultivations. The model provided a prediction of VCCs with relative errors from 5.5 to 11%, which is a good agreement with the acceptance criterion based on the offline reference method accuracy (approximately 10% relative error) and strongly improved compared with single-frequency results (16 to 23% relative error). Furthermore, robustness trials were conducted to demonstrate the model's predictive ability under challenging conditions. The process deviations in regard to dilution steps and feed variations were detected immediately in the online prediction of the VCC with relative errors between 6.7 and 13.2%. Thus in summary, the presented method on capacitance frequency scanning demonstrates its suitability for process monitoring and control that can save batches, time, and cost. Graphical abstract.
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Affiliation(s)
- Sabrina Metze
- Sartorius Stedim Biotech GmbH, August-Spindler-Str. 11, 37079, Göttingen, Germany.,Leibniz University of Hannover, Welfengarten 1, 30161, Hannover, Germany
| | - Stefanie Blioch
- Sartorius Stedim Biotech GmbH, August-Spindler-Str. 11, 37079, Göttingen, Germany
| | - Jens Matuszczyk
- Sartorius Stedim Biotech GmbH, August-Spindler-Str. 11, 37079, Göttingen, Germany
| | - Gerhard Greller
- Sartorius Stedim Biotech GmbH, August-Spindler-Str. 11, 37079, Göttingen, Germany
| | - Christian Grimm
- Sartorius Stedim Biotech GmbH, August-Spindler-Str. 11, 37079, Göttingen, Germany
| | - Jochen Scholz
- Sartorius Stedim Biotech GmbH, August-Spindler-Str. 11, 37079, Göttingen, Germany
| | - Marek Hoehse
- Sartorius Stedim Biotech GmbH, August-Spindler-Str. 11, 37079, Göttingen, Germany.
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8
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Monitoring online biomass with a capacitance sensor during scale-up of industrially relevant CHO cell culture fed-batch processes in single-use bioreactors. Bioprocess Biosyst Eng 2019; 43:193-205. [PMID: 31549309 PMCID: PMC6960217 DOI: 10.1007/s00449-019-02216-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/16/2019] [Accepted: 09/10/2019] [Indexed: 12/29/2022]
Abstract
In 2004, the FDA published a guideline to implement process analytical technologies (PAT) in biopharmaceutical processes for process monitoring to gain process understanding and for the control of important process parameters. Viable cell concentration (VCC) is one of the most important key performance indicator (KPI) during mammalian cell cultivation processes. Commonly, this is measured offline. In this work, we demonstrated the comparability and scalability of linear regression models derived from online capacitance measurements. The linear regressions were used to predict the VCC and other familiar offline biomass indicators, like the viable cell volume (VCV) and the wet cell weight (WCW), in two different industrially relevant CHO cell culture processes (Process A and Process B). Therefore, different single-use bioreactor scales (50–2000 L) were used to prove feasibility and scalability of the in-line sensor integration. Coefficient of determinations of 0.79 for Process A and 0.99 for Process B for the WCW were achieved. The VCV was described with high coefficients of determination of 0.96 (Process A) and 0.98 (Process B), respectively. In agreement with other work from the literature, the VCC was only described within the exponential growth phase, but resulting in excellent coefficients of determination of 0.99 (Process A) and 0.96 (Process B), respectively. Monitoring these KPIs online using linear regression models appeared to be scale-independent, enabled deeper process understanding (e.g. here demonstrated in monitoring, the feeding profile) and showed the potential of this method for process control.
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9
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Fazelkhah A, Afshar S, Braasch K, Butler M, Salimi E, Bridges G, Thomson D. Cytoplasmic conductivity as a marker for bioprocess monitoring: Study of Chinese hamster ovary cells under nutrient deprivation and reintroduction. Biotechnol Bioeng 2019; 116:2896-2905. [DOI: 10.1002/bit.27115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Azita Fazelkhah
- Department of Electrical and Computer EngineeringUniversity of Manitoba Winnipeg Canada
| | - Samaneh Afshar
- Department of Electrical and Computer EngineeringUniversity of Manitoba Winnipeg Canada
| | - Katrin Braasch
- Department of MicrobiologyUniversity of Manitoba Winnipeg Canada
| | - Michael Butler
- National Institute for Bioprocessing Research and Training Dublin Ireland
| | - Elham Salimi
- Department of Electrical and Computer EngineeringUniversity of Manitoba Winnipeg Canada
| | - Greg Bridges
- Department of Electrical and Computer EngineeringUniversity of Manitoba Winnipeg Canada
| | - Douglas Thomson
- Department of Electrical and Computer EngineeringUniversity of Manitoba Winnipeg Canada
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10
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Ma F, Zhang A, Chang D, Velev OD, Wiltberger K, Kshirsagar R. Real-time monitoring and control of CHO cell apoptosis by in situ multifrequency scanning dielectric spectroscopy. Process Biochem 2019. [DOI: 10.1016/j.procbio.2019.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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11
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Bielser JM, Domaradzki J, Souquet J, Broly H, Morbidelli M. Semi-continuous scale-down models for clone and operating parameter screening in perfusion bioreactors. Biotechnol Prog 2019; 35:e2790. [DOI: 10.1002/btpr.2790] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 01/07/2019] [Accepted: 02/13/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Jean-Marc Bielser
- Biotech Process Sciences, Merck Biopharma; Vevey Switzerland
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zürich; Zürich Switzerland
| | | | | | - Hervé Broly
- Biotech Process Sciences, Merck Biopharma; Vevey Switzerland
| | - Massimo Morbidelli
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zürich; Zürich Switzerland
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12
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Fernandes J, Currie J, Ramer K, Zhang A. Development of Capacitance Tools: At-Line Method for Assessing Biomass of Mammalian Cell Culture and Fixed Cell Calibration Standard. Biotechnol J 2018; 14:e1800283. [PMID: 30198629 DOI: 10.1002/biot.201800283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/01/2018] [Indexed: 12/15/2022]
Abstract
Capacitance is used to monitor "biomass" in cell culture and fermentation processes. The present work explores various ways to support good manufacturing practices (GMP) use and create robust methods that can assure proper performance of capacitance equipment. An at-line capacitance measurement method is particularly valuable as it can be used to correct or confirm online measurements from bioreactors. To obtain consistent predictions of online capacitance, the at-line method requires appropriate control of culture temperature, vessel geometry, mixing, and timing. The at-line method yields values that differ systematically from online values, but the variation is ≤11% for two cell lines tested. A cell line-specific conversion factor addresses the difference and enables accurate predictions of online capacitance values. In addition to the at-line method, verification of equipment performance is further enabled by using formaldehyde-treated cell standards. The cell-derived standards create a stabilized system for studying capacitance and recapitulate the performance of metabolically active cell culture. The formaldehyde-treated cells, however, require a much greater conversion factor to predict online outputs. The stabilized system proves useful for evaluation and calibration of capacitance measuring systems. The at-line method and stabilized cell-derived suspensions support use of capacitance for process control in large scale mammalian cell culture.
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Affiliation(s)
- Juhi Fernandes
- Manufacturing Sciences, Biogen, 5000 Davis Dr., Research Triangle Park, NC, 27709
| | - Jayme Currie
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695
| | - Kevin Ramer
- Manufacturing Sciences, Biogen, 5000 Davis Dr., Research Triangle Park, NC, 27709
| | - An Zhang
- Cell Culture Development, Biogen, 5000 Davis Dr., Research Triangle Park, NC, 27709
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13
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Perfusion mammalian cell culture for recombinant protein manufacturing – A critical review. Biotechnol Adv 2018; 36:1328-1340. [DOI: 10.1016/j.biotechadv.2018.04.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/26/2018] [Accepted: 04/30/2018] [Indexed: 01/04/2023]
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14
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Pan J, Shu Z, Ren S, Gao D. Determination of Dielectric Properties of Cryoprotective Agent Solutions with a Resonant Cavity for the Electromagnetic Rewarming in Cryopreservation. Biopreserv Biobank 2017; 15:404-409. [DOI: 10.1089/bio.2016.0096] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jiaji Pan
- Department of Mechanical Engineering, University of Washington, Seattle, Washington
| | - Zhiquan Shu
- Department of Mechanical Engineering, University of Washington, Seattle, Washington
- School of Mechanical and Materials Engineering, Washington State University, Everett, Washington
| | - Shen Ren
- Department of Mechanical Engineering, University of Washington, Seattle, Washington
| | - Dayong Gao
- Department of Mechanical Engineering, University of Washington, Seattle, Washington
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15
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Petiot E, Ansorge S, Rosa-Calatrava M, Kamen A. Critical phases of viral production processes monitored by capacitance. J Biotechnol 2016; 242:19-29. [PMID: 27867077 DOI: 10.1016/j.jbiotec.2016.11.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 11/07/2016] [Accepted: 11/10/2016] [Indexed: 11/28/2022]
Abstract
Over the last decade industrial manufacturing of viral vaccines and viral vectors for prophylactic and therapeutic applications is experiencing a remarkable growth. Currently, the quality attributes of viral derived products are assessed only at the end-point of the production process, essentially because in-process monitoring tools are not available or not implemented at industrial scale. However, to demonstrate process reproducibility and robustness, manufacturers are strongly advised by regulatory agencies to adopt more on-line process monitoring and control. Dielectric spectroscopy has been successfully used as an excellent indicator of the cell culture state in mammalian and yeast cell systems. We previously reported the use of this technique for monitoring influenza and lentiviral productions in HEK293 cell cultures. For both viruses, multi-frequency capacitance measurements allowed not only the on-line monitoring of the production kinetics, but also the identification of the viral release time from the cells. The present study demonstrates that the same approach can be successfully exploited for the on-line monitoring of different enveloped and non-enveloped virus production kinetics in cell culture processes. The on-line monitoring multi-frequency capacitance method was assessed in human HEK293 and Sf9 insect cells expression systems, with viral productions initiated by either infection or transfection. The comparative analyses of all the data acquired indicate that the characteristic capacitance signals were highly correlated with the occurrence of viral replication phases. Furthermore the evolution of the cell dielectric properties (intracellular conductivity and membrane capacitance) were indicative of each main replication steps. In conclusion, multi-frequency capacitance has a great potential for on-line monitoring, supervision and control of viral vector production in cell culture processes.
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Affiliation(s)
- Emma Petiot
- NRC, Human Health Therapeutics Portfolio, 6100 Royalmount Ave, Montréal, QC, H4P 2R2, Canada; Virologie et Pathologie Humaine - VirPath Team, International Center for Infectious diseases Research, Inserm U1111, CNRS UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Faculté de Médecine RTH Laennec, Lyon, France.
| | - Sven Ansorge
- NRC, Human Health Therapeutics Portfolio, 6100 Royalmount Ave, Montréal, QC, H4P 2R2, Canada.
| | - Manuel Rosa-Calatrava
- Virologie et Pathologie Humaine - VirPath Team, International Center for Infectious diseases Research, Inserm U1111, CNRS UMR5308, ENS Lyon, Université Claude Bernard Lyon 1, Faculté de Médecine RTH Laennec, Lyon, France.
| | - Amine Kamen
- NRC, Human Health Therapeutics Portfolio, 6100 Royalmount Ave, Montréal, QC, H4P 2R2, Canada; McGill University, Bioengineering Dpt. 817, Sherbrooke St. W., Montreal, QC, H2 B 2C6, Canada.
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Zalai D, Hevér H, Lovász K, Molnár D, Wechselberger P, Hofer A, Párta L, Putics Á, Herwig C. A control strategy to investigate the relationship between specific productivity and high-mannose glycoforms in CHO cells. Appl Microbiol Biotechnol 2016; 100:7011-24. [PMID: 26910040 PMCID: PMC4947490 DOI: 10.1007/s00253-016-7380-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/01/2016] [Accepted: 02/03/2016] [Indexed: 12/26/2022]
Abstract
The integration of physiological knowledge into process control strategies is a cornerstone for the improvement of biopharmaceutical cell culture technologies. The present contribution investigates the applicability of specific productivity as a physiological control parameter in a cell culture process producing a monoclonal antibody (mAb) in CHO cells. In order to characterize cell physiology, the on-line oxygen uptake rate (OUR) was monitored and the time-resolved specific productivity was calculated as physiological parameters. This characterization enabled to identify the tight link between the deprivation of tyrosine and the decrease in cell respiration and in specific productivity. Subsequently, this link was used to control specific productivity by applying different feeding profiles. The maintenance of specific productivity at various levels enabled to identify a correlation between the rate of product formation and the relative abundance of high-mannose glycoforms. An increase in high mannose content was assumed to be the result of high specific productivity. Furthermore, the high mannose content as a function of cultivation pH and specific productivity was investigated in a design of experiment approach. This study demonstrated how physiological parameters could be used to understand interactions between process parameters, physiological parameters, and product quality attributes.
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Affiliation(s)
- Dénes Zalai
- Department of Biotechnology, Gedeon Richter Plc., 19-21, Gyömrői út, Budapest, 1103, Hungary.,Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a, 1060, Vienna, Austria
| | - Helga Hevér
- Spectroscopic Research Department, Gedeon Richter Plc., 19-21, Gyömrői út, Budapest, 1103, Hungary
| | - Krisztina Lovász
- Department of Biotechnology, Gedeon Richter Plc., 19-21, Gyömrői út, Budapest, 1103, Hungary
| | - Dóra Molnár
- Department of Biotechnology, Gedeon Richter Plc., 19-21, Gyömrői út, Budapest, 1103, Hungary
| | - Patrick Wechselberger
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a, 1060, Vienna, Austria.,CD Laboratory for Mechanistic and Physiological Methods for Improved Bioprocesses, Vienna, Austria
| | - Alexandra Hofer
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a, 1060, Vienna, Austria
| | - László Párta
- Department of Biotechnology, Gedeon Richter Plc., 19-21, Gyömrői út, Budapest, 1103, Hungary
| | - Ákos Putics
- Department of Biotechnology, Gedeon Richter Plc., 19-21, Gyömrői út, Budapest, 1103, Hungary
| | - Christoph Herwig
- Institute of Chemical Engineering, Research Area Biochemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1a, 1060, Vienna, Austria. .,CD Laboratory for Mechanistic and Physiological Methods for Improved Bioprocesses, Vienna, Austria.
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Konakovsky V, Clemens C, Müller MM, Bechmann J, Berger M, Schlatter S, Herwig C. Metabolic Control in Mammalian Fed-Batch Cell Cultures for Reduced Lactic Acid Accumulation and Improved Process Robustness. Bioengineering (Basel) 2016; 3:bioengineering3010005. [PMID: 28952567 PMCID: PMC5597163 DOI: 10.3390/bioengineering3010005] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 09/25/2015] [Accepted: 01/04/2016] [Indexed: 01/17/2023] Open
Abstract
Biomass and cell-specific metabolic rates usually change dynamically over time, making the "feed according to need" strategy difficult to realize in a commercial fed-batch process. We here demonstrate a novel feeding strategy which is designed to hold a particular metabolic state in a fed-batch process by adaptive feeding in real time. The feed rate is calculated with a transferable biomass model based on capacitance, which changes the nutrient flow stoichiometrically in real time. A limited glucose environment was used to confine the cell in a particular metabolic state. In order to cope with uncertainty, two strategies were tested to change the adaptive feed rate and prevent starvation while in limitation: (i) inline pH and online glucose concentration measurement or (ii) inline pH alone, which was shown to be sufficient for the problem statement. In this contribution, we achieved metabolic control within a defined target range. The direct benefit was two-fold: the lactic acid profile was improved and pH could be kept stable. Multivariate Data Analysis (MVDA) has shown that pH influenced lactic acid production or consumption in historical data sets. We demonstrate that a low pH (around 6.8) is not required for our strategy, as glucose availability is already limiting the flux. On the contrary, we boosted glycolytic flux in glucose limitation by setting the pH to 7.4. This new approach led to a yield of lactic acid/glucose (Y L/G) around zero for the whole process time and high titers in our labs. We hypothesize that a higher carbon flux, resulting from a higher pH, may lead to more cells which produce more product. The relevance of this work aims at feeding mammalian cell cultures safely in limitation with a desired metabolic flux range. This resulted in extremely stable, low glucose levels, very robust pH profiles without acid/base interventions and a metabolic state in which lactic acid was consumed instead of being produced from day 1. With this contribution, we wish to extend the basic repertoire of available process control strategies, which will open up new avenues in automation technology and radically improve process robustness in both process development and manufacturing.
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Affiliation(s)
- Viktor Konakovsky
- Institute of Chemical Engineering, Division of Biochemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1A 166-4, 1060 Vienna, Austria.
| | - Christoph Clemens
- Boehringer Ingelheim Pharma GmbH & Co. KG Dep. Bioprocess Development, Biberach, Germany.
| | - Markus Michael Müller
- Boehringer Ingelheim Pharma GmbH & Co. KG Dep. Bioprocess Development, Biberach, Germany.
| | - Jan Bechmann
- Boehringer Ingelheim Pharma GmbH & Co. KG Dep. Bioprocess Development, Biberach, Germany.
| | - Martina Berger
- Boehringer Ingelheim Pharma GmbH & Co. KG Dep. Bioprocess Development, Biberach, Germany.
| | - Stefan Schlatter
- Boehringer Ingelheim Pharma GmbH & Co. KG Dep. Bioprocess Development, Biberach, Germany.
| | - Christoph Herwig
- Institute of Chemical Engineering, Division of Biochemical Engineering, Vienna University of Technology, Gumpendorfer Strasse 1A 166-4, 1060 Vienna, Austria.
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18
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Liu Y, Wang ZJ, Li L, Cui X, Chu J, Zhang SL, Zhuang YP. On-line monitoring of the aggregate size distribution of Carthamus tinctorius L. cells with multi-frequency capacitance measurements. RSC Adv 2016. [DOI: 10.1039/c6ra13527g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This study provided an effective methodology for the aggregate size distribution measurement of Carthamus tinctorius L. cells during suspension culture.
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Affiliation(s)
- Yu Liu
- State Key Laboratory of Bioreactor Engineering
- East China University of Science & Technology
- Shanghai 200237
- China
| | - Ze-Jian Wang
- State Key Laboratory of Bioreactor Engineering
- East China University of Science & Technology
- Shanghai 200237
- China
- Department of Biotechnology
| | - Lan Li
- State Key Laboratory of Bioreactor Engineering
- East China University of Science & Technology
- Shanghai 200237
- China
| | - Xiaolin Cui
- School of Chemical Engineering
- The University of Adelaide
- Adelaide
- Australia
| | - Ju Chu
- State Key Laboratory of Bioreactor Engineering
- East China University of Science & Technology
- Shanghai 200237
- China
| | - Si-Liang Zhang
- State Key Laboratory of Bioreactor Engineering
- East China University of Science & Technology
- Shanghai 200237
- China
| | - Ying-Ping Zhuang
- State Key Laboratory of Bioreactor Engineering
- East China University of Science & Technology
- Shanghai 200237
- China
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19
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Mercier SM, Rouel PM, Lebrun P, Diepenbroek B, Wijffels RH, Streefland M. Process analytical technology tools for perfusion cell culture. Eng Life Sci 2015. [DOI: 10.1002/elsc.201500035] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Sarah M. Mercier
- Vaccine Process and Analytical Development Janssen Leiden The Netherlands
| | - Perrine M. Rouel
- Vaccine Process and Analytical Development Janssen Leiden The Netherlands
| | | | - Bas Diepenbroek
- Vaccine Process and Analytical Development Janssen Leiden The Netherlands
| | - René H. Wijffels
- Bioprocess Engineering Wageningen University Wageningen The Netherlands
- Faculty of Biosciences and Aquaculture University of Nordland Bodø Norway
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20
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Zalai D, Tobak T, Putics Á. Impact of apoptosis on the on-line measured dielectric properties of CHO cells. Bioprocess Biosyst Eng 2015; 38:2427-37. [DOI: 10.1007/s00449-015-1479-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 09/28/2015] [Indexed: 12/20/2022]
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21
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Universal Capacitance Model for Real-Time Biomass in Cell Culture. SENSORS 2015; 15:22128-50. [PMID: 26364635 PMCID: PMC4610510 DOI: 10.3390/s150922128] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 07/18/2015] [Accepted: 08/25/2015] [Indexed: 11/17/2022]
Abstract
Capacitance probes have the potential to revolutionize bioprocess control due to their safe and robust use and ability to detect even the smallest capacitors in the form of biological cells. Several techniques have evolved to model biomass statistically, however, there are problems with model transfer between cell lines and process conditions. Errors of transferred models in the declining phase of the culture range for linear models around +100% or worse, causing unnecessary delays with test runs during bioprocess development. The goal of this work was to develop one single universal model which can be adapted by considering a potentially mechanistic factor to estimate biomass in yet untested clones and scales. The novelty of this work is a methodology to select sensitive frequencies to build a statistical model which can be shared among fermentations with an error between 9% and 38% (mean error around 20%) for the whole process, including the declining phase. A simple linear factor was found to be responsible for the transferability of biomass models between cell lines, indicating a link to their phenotype or physiology.
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22
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Dadehbeigi N, Dickson AJ. Chemical manipulation of the mTORC1 pathway in industrially relevant CHOK1 cells enhances production of therapeutic proteins. Biotechnol J 2015; 10:1041-50. [DOI: 10.1002/biot.201500075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/03/2015] [Accepted: 06/04/2015] [Indexed: 12/17/2022]
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23
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Schmidberger T, Posch C, Sasse A, Gülch C, Huber R. Progress toward forecasting product quality and quantity of mammalian cell culture processes by performance-based modeling. Biotechnol Prog 2015; 31:1119-27. [DOI: 10.1002/btpr.2105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 04/20/2015] [Indexed: 01/02/2023]
Affiliation(s)
| | | | | | - Carina Gülch
- Sandoz GmbH, Biochemiestrasse 10; Langkampfen 6336 Austria
| | - Robert Huber
- Dept. of Engineering and Management; University of Applied Sciences Munich; Lothstrasse 64 Munich 80335 Germany
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24
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Biechele P, Busse C, Solle D, Scheper T, Reardon K. Sensor systems for bioprocess monitoring. Eng Life Sci 2015. [DOI: 10.1002/elsc.201500014] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Philipp Biechele
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Christoph Busse
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Dörte Solle
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Thomas Scheper
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Kenneth Reardon
- Department of Chemical and Biological Engineering; Colorado State University; Fort Collins CO USA
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25
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Advanced near-infrared monitor for stable real-time measurement and control ofPichia pastorisbioprocesses. Biotechnol Prog 2014. [DOI: 10.1002/btpr.1890] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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26
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Downey BJ, Graham LJ, Breit JF, Glutting NK. A novel approach for using dielectric spectroscopy to predict viable cell volume (VCV) in early process development. Biotechnol Prog 2014; 30:479-87. [PMID: 24851255 PMCID: PMC4162991 DOI: 10.1002/btpr.1845] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 12/11/2013] [Indexed: 12/02/2022]
Abstract
Online monitoring of viable cell volume (VCV) is essential to the development, monitoring, and control of bioprocesses. The commercial availability of steam-sterilizable dielectricspectroscopy probes has enabled successful adoption of this technology as a key noninvasive method to measure VCV for cell-culture processes. Technological challenges still exist, however. For some cell lines, the technique’s accuracy in predicting the VCV from probepermittivity measurements declines as the viability of the cell culture decreases. To investigate the cause of this decrease in accuracy, divergences in predicted vs. actual VCV measurements were directly related to the shape of dielectric frequency scans collected during a cell culture. The changes in the shape of the beta dispersion, which are associated with changes in cell state, are quantified by applying a novel “area ratio” (AR) metric to frequency-scanning data from the dielectric-spectroscopy probes. The AR metric is then used to relate the shape of the beta dispersion to single-frequency permittivity measurements to accurately predict the offline VCV throughout an entire fed-batch run, regardless of cell state. This work demonstrates the possible feasibility of quantifying the shape of the beta dispersion, determined from frequency-scanning data, for enhanced measurement of VCV in mammalian cell cultures by applying a novel shape-characterization technique. In addition, this work demonstrates the utility of using changes in the shape of the beta dispersion to quantify cell health.
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27
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Schmidberger T, Gutmann R, Bayer K, Kronthaler J, Huber R. Advanced online monitoring of cell culture off-gas using proton transfer reaction mass spectrometry. Biotechnol Prog 2014; 30:496-504. [DOI: 10.1002/btpr.1853] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/02/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Timo Schmidberger
- Sandoz GmbH; 6336 Langkampfen Austria
- Dept. of Biotechnology; University of Natural Resources and Life Sciences; 1180 Vienna Austria
| | | | - Karl Bayer
- Dept. of Biotechnology; University of Natural Resources and Life Sciences; 1180 Vienna Austria
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28
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Braasch K, Nikolic-Jaric M, Cabel T, Salimi E, Bridges GE, Thomson DJ, Butler M. The changing dielectric properties of CHO cells can be used to determine early apoptotic events in a bioprocess. Biotechnol Bioeng 2013; 110:2902-14. [PMID: 23818314 DOI: 10.1002/bit.24976] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 05/23/2013] [Accepted: 06/03/2013] [Indexed: 12/21/2022]
Abstract
To ensure maximum productivity of recombinant proteins it is desirable to prolong cell viability during a mammalian cell bioprocess, and therefore important to carefully monitor cell density and viability. In this study, five different and independent methods of monitoring were applied to Chinese hamster ovary (CHO) cells grown in a batch culture in a controlled bioreactor to determine cell density and/or cell viability. They included: a particle counter, trypan blue exclusion (Cedex), an in situ bulk capacitance probe, an off-line fluorescent flow cytometer, and a prototype dielectrophoretic (DEP) cytometer. These various techniques gave similar values during the exponential growth phase. However, beyond the exponential growth phase the viability measurements diverged. Fluorescent flow cytometry with a range of fluorescent markers was used to investigate this divergence and to establish the progress of cell apoptosis: the cell density estimates by the intermediate stage apoptosis assay agreed with those obtained by the bulk capacitance probe and the early stage apoptosis assay viability measurements correlated well with the DEP cytometer. The trypan blue assay showed higher estimates of viable cell density and viability compared to the capacitance probe or the DEP cytometer. The DEP cytometer measures the dielectric properties of individual cells and identified at least two populations of cells, each with a distinct polarizability. As verified by comparison with the Nexin assay, one population was associated with viable (non-apoptotic) cells and the other with apoptotic cells. From the end of the exponential through the stationary and decline stages there was a gradual shift of cell count from the viable into the apoptotic population. However, the two populations maintained their individual dielectric properties throughout this shift. This leads to the conclusion that changes in bulk dielectric properties of cultures might be better modeled as shifts in cells between different dielectric sub-populations, rather than assuming a homogeneous dielectric population. This shows that bulk dielectric probes are sensitive to the early apoptotic changes in cells. DEP cytometry offers a novel and unique technology for analyzing and characterizing mammalian cells based on their dielectric properties, and suggests a potential application of the device as a low-cost, label-free, electronic monitor of physiological changes in cells.
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Affiliation(s)
- Katrin Braasch
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
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29
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Párta L, Zalai D, Borbély S, Putics Á. Application of dielectric spectroscopy for monitoring high cell density in monoclonal antibody producing CHO cell cultivations. Bioprocess Biosyst Eng 2013; 37:311-23. [DOI: 10.1007/s00449-013-0998-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 06/10/2013] [Indexed: 10/26/2022]
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30
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El Wajgali A, Esteban G, Fournier F, Pinton H, Marc A. Impact of microcarrier coverage on using permittivity for on-line monitoring high adherent Vero cell densities in perfusion bioreactors. Biochem Eng J 2013. [DOI: 10.1016/j.bej.2012.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Emma P, Kamen A. Real-time monitoring of influenza virus production kinetics in HEK293 cell cultures. Biotechnol Prog 2012; 29:275-84. [PMID: 22848016 DOI: 10.1002/btpr.1601] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 07/16/2012] [Indexed: 12/22/2022]
Abstract
There is an increased interest from the vaccine industry to use mammalian cell cultures for influenza vaccine manufacturing. Therefore, it became important to study the influenza infection mechanism, the viral-host interaction, and the replication kinetics from a bioprocessing stand point to maximize the influenza viral production yield in cell culture. In the present work, influenza replication kinetics was studied in HEK293 cells. Two infection conditions were evaluated, a low (0.01) and a high multiplicity of infection (1.0). Critical time points of the viral production cycle (infection, protein synthesis, viral assembly and budding, viral release, and host-cell death) were identified in small-scale cell cultures. Additionally, cell growth, viability, and viral titers were monitored in the viral production process. The infection state of the cultivated cell population was assessed by influenza immunolabeling throughout the culture period. Influenza virus production kinetics were also on-line monitored by dielectric spectroscopy and successfully correlated to real-time capacitance measures. Overall, this work provided insights into the mechanisms associated with the infection of human HEK293 cell line by the influenza virus and demonstrated, once again, the usefulness of multifrequency scanning permittivity for in-line monitoring and supervision of cell-based viral production processes.
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Affiliation(s)
- Petiot Emma
- National Research Council, Bioprocessing and Manufacturing, Vaccine Program, Montreal, QC, Canada
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32
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Sonnleitner B. Automated measurement and monitoring of bioprocesses: key elements of the M(3)C strategy. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2012. [PMID: 23179291 DOI: 10.1007/10_2012_173] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
The state-of-routine monitoring items established in the bioprocess industry as well as some important state-of-the-art methods are briefly described and the potential pitfalls discussed. Among those are physical and chemical variables such as temperature, pressure, weight, volume, mass and volumetric flow rates, pH, redox potential, gas partial pressures in the liquid and molar fractions in the gas phase, infrared spectral analysis of the liquid phase, and calorimetry over an entire reactor. Classical as well as new optical versions are addressed. Biomass and bio-activity monitoring (as opposed to "measurement") via turbidity, permittivity, in situ microscopy, and fluorescence are critically analyzed. Some new(er) instrumental analytical tools, interfaced to bioprocesses, are explained. Among those are chromatographic methods, mass spectrometry, flow and sequential injection analyses, field flow fractionation, capillary electrophoresis, and flow cytometry. This chapter surveys the principles of monitoring rather than compiling instruments.
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Affiliation(s)
- Bernhard Sonnleitner
- Institute for Chemistry and Biological Chemistry (ICBC), Zurich University of Applied Sciences (ZHAW), Einsiedlerstrasse 29, CH-8820, Waedenswil, Switzerland,
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33
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Aehle M, Kuprijanov A, Schaepe S, Simutis R, Lübbert A. Increasing batch-to-batch reproducibility of CHO cultures by robust open-loop control. Cytotechnology 2010; 63:41-7. [PMID: 21057872 DOI: 10.1007/s10616-010-9320-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022] Open
Abstract
In order to guarantee the quality of recombinant therapeutic proteins produced in mammalian cell systems, the straightforward approach in industry is to run the processes as reproducible as possible. It is first shown that considerable distortions in the currently operated processes appear when the initial cell density deviates from its nominal value. Small deviations in the initial cell mass may lead to severe deviations from the desired biomass trajectory. Next, it is shown how to design a fed-batch production process in such a way that it is robust with respect to variations in the viable cell density. A simple open loop strategy is proposed for that purpose. Here we show for the first time at animal cell cultures (CHO cells) that by means of an appropriate glutamine feed rate profile F(t), which keeps the specific growth rate of the cells on a predefined value below its maximal value while maintaining the viabilities on a high level, the diverging viable cell count profiles change over into a robust converging set of profiles. The CHO cells used to validate the procedure could be focused to any specific growth rates below μ(max).
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Affiliation(s)
- M Aehle
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, 06120, Halle (Saale), Germany
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