1
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Breen L, Flynn J, Bergin A, Flampouri E, Butler M. Single cell analysis of Chinese hamster ovary cells during a bioprocess using a novel dynamic imaging system. Biotechnol Prog 2024:e3469. [PMID: 38613439 DOI: 10.1002/btpr.3469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/15/2024]
Abstract
Reliable monitoring of mammalian cells in bioreactors is essential to biopharmaceutical production. Trypan blue exclusion is a method of determining cell density and viability that has been used for over one hundred years to monitor cells in culture and is the current standard method in biomanufacturing. This method has many disadvantages however and there is a growing demand for more detailed and in-line measurements of cell growth in bioreactors. This article assesses a novel dynamic imaging system for single cell analysis. This data shows that comparable total cell density, viable cell density and percentage viability data shown here, generated by the imaging system, aligned well with conventional trypan blue counting methods for an industrially relevant Chinese Hamster Ovary (CHO) cell line. Furthermore, detailed statistical analysis shows that the classification system used by the PharmaFlow system can reveal trends of interest in monitoring the health of mammalian cells over a 6-day bioreactor culture. The system is also capable of sampling at-line, removing the necessity for taking samples off-line and enabling real time monitoring of cells in a bioreactor culture.
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Affiliation(s)
- Laura Breen
- Cell Technology Group, National Institute for Bioprocessing Research and Training (NIBRT), Blackrock, Co., Dublin, Ireland
| | - James Flynn
- Cell Technology Group, National Institute for Bioprocessing Research and Training (NIBRT), Blackrock, Co., Dublin, Ireland
| | - Adam Bergin
- Cell Technology Group, National Institute for Bioprocessing Research and Training (NIBRT), Blackrock, Co., Dublin, Ireland
- School of Chemical and Bioprocess Engineering, University College Dublin (UCD), Blackrock, Co., Dublin, Ireland
| | - Evangelia Flampouri
- Cell Technology Group, National Institute for Bioprocessing Research and Training (NIBRT), Blackrock, Co., Dublin, Ireland
| | - Michael Butler
- Cell Technology Group, National Institute for Bioprocessing Research and Training (NIBRT), Blackrock, Co., Dublin, Ireland
- School of Chemical and Bioprocess Engineering, University College Dublin (UCD), Blackrock, Co., Dublin, Ireland
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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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Liu Z, Jiang X, Li S, Chen J, Jiang C, Wang K, Zhang C, Wang B. A disposable impedance-based sensor for in-line cell growth monitoring in CAR-T cell manufacturing. Bioelectrochemistry 2023; 152:108416. [PMID: 37023618 DOI: 10.1016/j.bioelechem.2023.108416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/17/2023] [Accepted: 03/18/2023] [Indexed: 04/08/2023]
Abstract
This paper presents the development of low-cost, disposable impedance-based sensors for real-time, in-line monitoring of suspension cell culture. The sensors consist of electrical discharge machining (EDM) cut aluminum electrodes and polydimethylsiloxane (PDMS) spacers, both of which are low-cost materials that can be safely disposed of. Our research demonstrates the capability of these low-cost sensors for in-line, non-invasive monitoring of suspension cell growth in cell manufacturing. We use a hybrid equivalent circuit model to extract key features/parameters from intertwined impedance signals, which are then fed to a novel physics-inspired (gray-box) model designed for α-relaxation. This model determines viable cell count (VCC), a critical quality attribute (CQA) in cell manufacturing. Predicted VCC trends are then compared with image-based cell count data to verify their accuracy.
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Affiliation(s)
- Zhaonan Liu
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta 30332, United States
| | - Xuzhou Jiang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States
| | - Shuai Li
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States
| | - Jialei Chen
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta 30332, United States
| | - Chen Jiang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta 30332, United States
| | - Kan Wang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States
| | - Chuck Zhang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta 30332, United States.
| | - Ben Wang
- Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta 30332, United States; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta 30332, United States; H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta 30332, United States
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4
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Gillette AA, Pham DL, Skala MC. Touch-free optical technologies to streamline the production of T cell therapies. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2023; 25:100434. [PMID: 36642996 PMCID: PMC9837746 DOI: 10.1016/j.cobme.2022.100434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Currently approved adoptive T cell therapy relies on autologous (obtained from the same patient) T cells, which often suffer from poor quality that diminishes treatment efficacy. Due to the heterogeneous nature of T cell quality between and within patients, significant efforts are aimed at optimizing cell manipulation and growth conditions for potent T cell products. We believe that touch-free imaging and sensing technologies are critical to monitor single-cell features during T cell manufacturing to ensure consistent and optimally timed methods for cell manipulation and growth. Here, we discuss emerging label-free optical imaging and sensing methods, along with machine learning techniques that could enable in-line feedback to optimize T cell quality at multiple stages during manufacturing. These methods have the potential to streamline current workflow, accelerate the manufacture of safe high-quality T cell therapies, and improve our understanding of the dynamic, heterogeneous processes of T cell manufacturing.
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Affiliation(s)
| | - Dan L Pham
- Department of Biomedical Engineering, University of Wisconsin-Madison
| | - Melissa C Skala
- Morgridge Institute for Research, Madison, Wisconsin
- Department of Biomedical Engineering, University of Wisconsin-Madison
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5
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Bergin A, Carvell J, Butler M. Applications of bio-capacitance to cell culture manufacturing. Biotechnol Adv 2022; 61:108048. [DOI: 10.1016/j.biotechadv.2022.108048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/05/2022] [Accepted: 09/30/2022] [Indexed: 11/16/2022]
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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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Swaminathan N, Priyanka P, Rathore AS, Sivaprakasam S, Subbiah S. Multiobjective Optimization for Enhanced Production of Therapeutic Proteins in Escherichia coli: Application of Real-Time Dielectric Spectroscopy. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.0c04010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nivedhitha Swaminathan
- Centre for the Environment, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Priyanka Priyanka
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Anurag S. Rathore
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Senthilkumar Sivaprakasam
- Centre for the Environment, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Senthilmurugan Subbiah
- Centre for the Environment, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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8
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Moore B, Grinnell C, Boumajny B, Chen R, Frenkel R, Vilmorin P, Sosic Z, Khattak S. A multi‐faceted approach to analyzing glucose heat‐degradants and evaluating impact to a
CHO
cell culture process. AIChE J 2020. [DOI: 10.1002/aic.16295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Brandon Moore
- Cell Culture DevelopmentBiogen Durham North Carolina USA
| | - Chris Grinnell
- Materials ScienceBiogen Davis Dr. Durham North Carolina USA
| | - Boris Boumajny
- Analytical DevelopmentBiogen Cambridge Massachusetts USA
| | - Rachel Chen
- Analytical DevelopmentBiogen Cambridge Massachusetts USA
| | - Ruth Frenkel
- Analytical DevelopmentBiogen Cambridge Massachusetts USA
| | - Phil Vilmorin
- Materials ScienceBiogen Davis Dr. Durham North Carolina USA
| | - Zoran Sosic
- Analytical DevelopmentBiogen Cambridge Massachusetts USA
| | - Sarwat Khattak
- Cell Culture DevelopmentBiogen Durham North Carolina USA
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9
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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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10
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Turbidimetry and Dielectric Spectroscopy as Process Analytical Technologies for Mammalian and Insect Cell Cultures. Methods Mol Biol 2020; 2095:335-364. [PMID: 31858478 DOI: 10.1007/978-1-0716-0191-4_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The production of biopharmaceuticals in cell culture involves stringent controls to ensure product safety and quality. To meet these requirements, quality by design principles must be applied during the development of cell culture processes so that quality is built into the product by understanding the manufacturing process. One key aspect is process analytical technology, in which comprehensive online monitoring is used to identify and control critical process parameters that affect critical quality attributes such as the product titer and purity. The application of industry-ready technologies such as turbidimetry and dielectric spectroscopy provides a deeper understanding of biological processes within the bioreactor and allows the physiological status of the cells to be monitored on a continuous basis. This in turn enables selective and targeted process controls to respond in an appropriate manner to process disturbances. This chapter outlines the principles of online dielectric spectroscopy and turbidimetry for the measurement of optical density as applied to mammalian and insect cells cultivated in stirred-tank bioreactors either in suspension or as adherent cells on microcarriers.
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11
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Dahlmann K, Busse C, Aupert F, de Vries I, Marquard D, Solle D, Lammers F, Scheper T. Online monitoring of the cell-specific oxygen uptake rate with an in situ combi-sensor. Anal Bioanal Chem 2019; 412:2111-2121. [PMID: 31802179 DOI: 10.1007/s00216-019-02260-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 10/28/2019] [Accepted: 11/05/2019] [Indexed: 11/30/2022]
Abstract
In a biotechnological process, standard monitored process variables are pH, partial oxygen pressure (pO2), and temperature. These process variables are important, but they do not give any information about the metabolic activity of the cell. The ISICOM is an in situ combi-sensor that is measuring the cell-specific oxygen uptake rate (qOUR) online. This variable allows a qualitative judgement of metabolic cell activity. The measuring principle of the ISICOM is based on a volume element enclosed into a small measuring chamber. Inside the measuring chamber, the pO2 and the scattered light is measured. Within a defined measuring interval, the chamber closes, and the oxygen supply for the cells is interrupted. The decreasing oxygen concentration is recorded by the pO2 optode. This measuring principle, known as the dynamic method, determines the oxygen uptake rate (OUR). Together with the scattered light signal, the cell concentration is estimated and the qOUR is available online. The design of the ISICOM is focused on functionality, sterility, long-term stability, and response time behavior so the sensor can be used in bioprocesses. With the ISICOM, measurement of online and in situ measurement of the OUR is possible. The OUR and qOUR online measurement of an animal cell batch cultivation is demonstrated, with maximum values of OUR = 2.5 mmol L-1 h-1 and a qOUR = 9.5 pmol cell-1 day-1. Information about limitation of the primary and secondary substrate is derived by the monitoring of the metabolic cell activity of bacteria and yeast cultivation processes. This sensor contributes to a higher process understanding by offering an online view on to the cell behavior. In the sense of process analytical technology (PAT), this important information is needed for bioprocesses to realize a knowledge base process control.
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Affiliation(s)
- Katharina Dahlmann
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, 30167, Hannover, Germany
| | - Christoph Busse
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, 30167, Hannover, Germany
| | - Florian Aupert
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, 30167, Hannover, Germany
| | - Ingo de Vries
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, 30167, Hannover, Germany
| | - Daniel Marquard
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, 30167, Hannover, Germany
| | - Dörte Solle
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, 30167, Hannover, Germany.
| | - Frank Lammers
- Sanofi, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Thomas Scheper
- Institut für Technische Chemie, Gottfried Wilhelm Leibniz Universität Hannover, Callinstraße 5, 30167, Hannover, Germany
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12
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Nie J, Sun Y, Peng F, Li X, Yang Y, Liu X, Li Y, Liu C, Bai Z. Production Process Development of Pseudorabies Virus Vaccine by Using a Novel Scale-Down Model of a Fixed-Bed Bioreactor. J Pharm Sci 2019; 109:959-965. [PMID: 31604085 DOI: 10.1016/j.xphs.2019.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/18/2019] [Accepted: 10/01/2019] [Indexed: 12/22/2022]
Abstract
In this study, a novel tube-fixed-bed bioreactor which consists of a TubeSpin bioreactor 50 tube and 0.44 g macrocarriers was developed as the scale-down model of a fixed-bed bioreactor. The adherent Vero cell-based pseudorabies virus (PRV) production process was tested in this novel model. The Vero cells grew well in the tube-fixed-bed bioreactor, and the cell density reached 5.8 × 106 cells/mL after 7 days of culture. The PRV production parameters (time of infection, multiplicity of infection, and harvest process) were optimized in the tube-fixed-bed bioreactor. Then the optimized process (time of infection = 3 days, multiplicity of infection = 0.001 and multiple harvest process) was scaled up 25-fold to an Xcell 1-L laboratory-scale fixed-bed bioreactor and 125-fold to an Xcell 5-L fixed-bed bioreactor successfully. The total PRV harvest in the Xcell 1-L bioreactor at 5 days after infection (dpi) was 10.25 log10 TCID50 which corresponds to 177,827 doses of vaccine. The total PRV harvest in the Xcell 5-L bioreactor at 5 dpi was 11.13 log10 TCID50 which corresponded to 1,348,962 doses of vaccine. The comparable growth curve, metabolism, and PRV production profile of the scaled-up bioreactors confirmed the feasibility and scalability of the tube-fixed-bed bioreactor as a scale-down model of the fixed-bed bioreactor for virus production process development.
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Affiliation(s)
- Jianqi Nie
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
| | - Yang Sun
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
| | - Feng Peng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
| | - Xinran Li
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China
| | - Yankun Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xiuxia Liu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, China
| | - Ye Li
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, China
| | - Chunli Liu
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, China
| | - Zhonghu Bai
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi 214122, China.
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13
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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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Gamal W, Wu H, Underwood I, Jia J, Smith S, Bagnaninchi PO. Impedance-based cellular assays for regenerative medicine. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0226. [PMID: 29786561 DOI: 10.1098/rstb.2017.0226] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2018] [Indexed: 12/22/2022] Open
Abstract
Therapies based on regenerative techniques have the potential to radically improve healthcare in the coming years. As a result, there is an emerging need for non-destructive and label-free technologies to assess the quality of engineered tissues and cell-based products prior to their use in the clinic. In parallel, the emerging regenerative medicine industry that aims to produce stem cells and their progeny on a large scale will benefit from moving away from existing destructive biochemical assays towards data-driven automation and control at the industrial scale. Impedance-based cellular assays (IBCA) have emerged as an alternative approach to study stem-cell properties and cumulative studies, reviewed here, have shown their potential to monitor stem-cell renewal, differentiation and maturation. They offer a novel method to non-destructively assess and quality-control stem-cell cultures. In addition, when combined with in vitro disease models they provide complementary insights as label-free phenotypic assays. IBCA provide quantitative and very sensitive results that can easily be automated and up-scaled in multi-well format. When facing the emerging challenge of real-time monitoring of three-dimensional cell culture dielectric spectroscopy and electrical impedance tomography represent viable alternatives to two-dimensional impedance sensing.This article is part of the theme issue 'Designer human tissue: coming to a lab near you'.
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Affiliation(s)
- W Gamal
- School of Electronic Engineering, Bangor University, Bangor LL57 1UT, UK
| | - H Wu
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, UK
| | - I Underwood
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, UK
| | - J Jia
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, UK
| | - S Smith
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, UK
| | - P O Bagnaninchi
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh EH16 4UU, UK
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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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16
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Moore B, Sanford R, Zhang A. Case study: The characterization and implementation of dielectric spectroscopy (biocapacitance) for process control in a commercial GMP CHO manufacturing process. Biotechnol Prog 2019; 35:e2782. [DOI: 10.1002/btpr.2782] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 12/20/2018] [Accepted: 01/28/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Brandon Moore
- Cell Culture Development; Biogen, Research Triangle Park; North Carolina
| | - Ryan Sanford
- Cell Culture Development; Biogen, Research Triangle Park; North Carolina
| | - An Zhang
- Cell Culture Development; Biogen, Research Triangle Park; North Carolina
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17
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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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18
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Narayanan LK, Thompson TL, Shirwaiker RA, Starly B. Label free process monitoring of 3D bioprinted engineered constructs via dielectric impedance spectroscopy. Biofabrication 2018; 10:035012. [PMID: 29901449 DOI: 10.1088/1758-5090/aaccbf] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Biofabrication processes can affect biological quality attributes of encapsulated cells within constructs. Currently, assessment of the fabricated constructs is performed offline by subjecting the constructs to destructive assays that require staining and sectioning. This drawback limits the translation of biofabrication processes to industrial practice. In this work, we investigate the dielectric response of viable cells encapsulated in bioprinted 3D hydrogel constructs to an applied alternating electric field as a label-free non-destructive monitoring approach. The relationship between β-dispersion parameters (permittivity change-Δε, Cole-Cole slope factor-α, critical polarization frequency-f c ) over the frequency spectrum and critical cellular quality attributes are investigated. Results show that alginate constructs containing a higher number of viable cells (human adipose derived stem cells-hASC and osteosarcoma cell line-MG63) were characterized by significantly higher Δε and α (both p < 0.05). When extended to bioprinting, results showed that changes in hASC proliferation and viability in response to changes in critical bioprinting parameters (extrusion pressure, temperature, processing time) significantly affected ∆ε, α, and f c . We also demonstrated monitoring of hASC distribution after bioprinting and changes in proliferation over time across the cross-section of a bioprinted medial knee meniscus construct. The trends in ∆ε over time were in agreement with the alamarBlue assay results for the whole construct, but this measurement approach provided a localized readout on the status of encapsulated cells. The findings of this study support the use of dielectric impedance spectroscopy as a label-free and non-destructive method to characterize the critical quality attributes of bioprinted constructs.
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Affiliation(s)
- Lokesh Karthik Narayanan
- Edward P Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, NC 27695, United States of America. Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27695, United States of America
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19
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Wu H, Zhou W, Yang Y, Jia J, Bagnaninchi P. Exploring the Potential of Electrical Impedance Tomography for Tissue Engineering Applications. MATERIALS 2018; 11:ma11060930. [PMID: 29857521 PMCID: PMC6025244 DOI: 10.3390/ma11060930] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 12/17/2022]
Abstract
In tissue engineering, cells are generally cultured in biomaterials to generate three-dimensional artificial tissues to repair or replace damaged parts and re-establish normal functions of the body. Characterizing cell growth and viability in these bioscaffolds is challenging, and is currently achieved by destructive end-point biological assays. In this study, we explore the potential to use electrical impedance tomography (EIT) as a label-free and non-destructive technology to assess cell growth and viability. The key challenge in the tissue engineering application is to detect the small change of conductivity associated with sparse cell distributions in regards to the size of the hosting scaffold, i.e., low volume fraction, until they assemble into a larger tissue-like structure. We show proof-of-principle data, measure cells within both a hydrogel and a microporous scaffold with an ad-hoc EIT equipment, and introduce the frequency difference technique to improve the reconstruction.
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Affiliation(s)
- Hancong Wu
- Agile Tomography Group, School of Engineering, The University of Edinburgh, Edinburgh EH9 3JL, UK; (H.W.).
| | - Wenli Zhou
- Department of Medical Oncology, Changzheng Hospital, Navy Medical University, Shanghai 200070, China.
| | - Yunjie Yang
- Agile Tomography Group, School of Engineering, The University of Edinburgh, Edinburgh EH9 3JL, UK; (H.W.).
| | - Jiabin Jia
- Agile Tomography Group, School of Engineering, The University of Edinburgh, Edinburgh EH9 3JL, UK; (H.W.).
| | - Pierre Bagnaninchi
- MRC Centre for Regenerative Medicine, The University of Edinburgh, Edinburgh EH16 4UU, UK.
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20
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Dielectric Spectroscopy and Optical Density Measurement for the Online Monitoring and Control of Recombinant Protein Production in Stably Transformed Drosophila melanogaster S2 Cells. SENSORS 2018; 18:s18030900. [PMID: 29562633 PMCID: PMC5876727 DOI: 10.3390/s18030900] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 01/30/2023]
Abstract
The production of recombinant proteins in bioreactors requires real-time process monitoring and control to increase process efficiency and to meet the requirements for a comprehensive audit trail. The combination of optical near-infrared turbidity sensors and dielectric spectroscopy provides diverse system information because different measurement principles are exploited. We used this combination of techniques to monitor and control the growth and protein production of stably transformed Drosophila melanogaster S2 cells expressing antimicrobial proteins. The in situ monitoring system was suitable in batch, fed-batch and perfusion modes, and was particularly useful for the online determination of cell concentration, specific growth rate (µ) and cell viability. These data were used to pinpoint the optimal timing of the key transitional events (induction and harvest) during batch and fed-batch cultivation, achieving a total protein yield of ~25 mg at the 1-L scale. During cultivation in perfusion mode, the OD880 signal was used to control the bleed line in order to maintain a constant cell concentration of 5 × 107 cells/mL, thus establishing a turbidostat/permittistat culture. With this setup, a five-fold increase in productivity was achieved and 130 mg of protein was recovered after 2 days of induced perfusion. Our results demonstrate that both sensors are suitable for advanced monitoring and integration into online control strategies.
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21
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Grein TA, Loewe D, Dieken H, Salzig D, Weidner T, Czermak P. High titer oncolytic measles virus production process by integration of dielectric spectroscopy as online monitoring system. Biotechnol Bioeng 2018; 115:1186-1194. [DOI: 10.1002/bit.26538] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/30/2017] [Accepted: 12/26/2017] [Indexed: 02/06/2023]
Affiliation(s)
- Tanja A. Grein
- Institute of Bioprocess Engineering Pharmaceutical Technology; University of Applied Sciences Mittelhessen; Giessen Germany
| | - Daniel Loewe
- Institute of Bioprocess Engineering Pharmaceutical Technology; University of Applied Sciences Mittelhessen; Giessen Germany
| | - Hauke Dieken
- Institute of Bioprocess Engineering Pharmaceutical Technology; University of Applied Sciences Mittelhessen; Giessen Germany
| | - Denise Salzig
- Institute of Bioprocess Engineering Pharmaceutical Technology; University of Applied Sciences Mittelhessen; Giessen Germany
| | - Tobias Weidner
- Institute of Bioprocess Engineering Pharmaceutical Technology; University of Applied Sciences Mittelhessen; Giessen Germany
| | - Peter Czermak
- Institute of Bioprocess Engineering Pharmaceutical Technology; University of Applied Sciences Mittelhessen; Giessen Germany
- Faculty of Biology and Chemistry; Justus Liebig University; Giessen Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME); Project group Bioresources; Giessen Germany
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22
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Amini M, Hisdal J, Kalvøy H. Applications of Bioimpedance Measurement Techniques in Tissue Engineering. JOURNAL OF ELECTRICAL BIOIMPEDANCE 2018; 9:142-158. [PMID: 33584930 PMCID: PMC7852004 DOI: 10.2478/joeb-2018-0019] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Indexed: 05/19/2023]
Abstract
Rapid development in the field of tissue engineering necessitates implementation of monitoring methods for evaluation of the viability and characteristics of the cell cultures in a real-time, non-invasive and non-destructive manner. Current monitoring techniques are mainly histological and require labeling and involve destructive tests to characterize cell cultures. Bioimpedance measurement technique which benefits from measurement of electrical properties of the biological tissues, offers a non-invasive, label-free and real-time solution for monitoring tissue engineered constructs. This review outlines the fundamentals of bioimpedance, as well as electrical properties of the biological tissues, different types of cell culture constructs and possible electrode configuration set ups for performing bioimpedance measurements on these cell cultures. In addition, various bioimpedance measurement techniques and their applications in the field of tissue engineering are discussed.
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Affiliation(s)
- M. Amini
- Department of Physics, University of Oslo, Oslo, Norway
| | - J. Hisdal
- Vascular Investigations and Circulation lab, Aker Hospital, Oslo University Hospital, Oslo, Norway
| | - H. Kalvøy
- Department of Clinical and Biomedical Engineering, Rikshospitalet, Oslo University Hospital, Oslo, Norway
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23
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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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25
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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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26
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The Application of Dielectric Spectroscopy and Biocalorimetry for the Monitoring of Biomass in Immobilized Mammalian Cell Cultures. Processes (Basel) 2015. [DOI: 10.3390/pr3020384] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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27
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In silico validation procedure for cell volume fraction estimation through dielectric spectroscopy. J Biol Phys 2015; 41:223-34. [PMID: 25572442 DOI: 10.1007/s10867-014-9374-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/07/2014] [Indexed: 10/24/2022] Open
Abstract
Dielectric spectroscopy has proved to be a good tool for analyzing the passive electrical properties of biological tissues as well as those of inhomogeneous materials. This technique promises to be a valid alternative to the classical ones based on metabolites to monitor the growth and cell volume fraction of cell cultures in a simple and minimally invasive way. In order to obtain an accurate estimation of the cell volume fraction as a function of the permittivity of the suspension, a simple in silico procedure is proposed. The procedure is designed to perform homogenization from the micro-scale to the macro-scale using simple analytical models and simulation setups hypothesizing the properties of diluted suspension (cell volume fraction less than 0.2). Results obtained show the possibility to overcome some trouble involving the analytical treatment of the cellular shape by considering a sphere with the same permittivity in the quantitative analysis of the cell volume fraction. The entire study is based on computer simulations performed in order to verify the correctness of the procedure. Obtained data are used in a cell volume fraction estimation scenario to show the effectiveness of the procedure.
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28
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29
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Kazantzis N, Kazantzi V, Christodoulou EG. Pollutant concentration profile reconstruction using digital soft sensors for biodegradation and exposure assessment in the presence of model uncertainty. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:9553-9568. [PMID: 24584587 DOI: 10.1007/s11356-014-2572-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 01/20/2014] [Indexed: 06/03/2023]
Abstract
A new approach to the problem of environmental hazard assessment and monitoring for pollutant biodegradation reaction systems in the presence of uncertainty is proposed using soft sensor-based pollutant concentration dynamic profile reconstruction techniques. In particular, a robust reduced-order soft sensor is proposed that can be digitally implemented in the presence of inherent complexity and the inevitable model uncertainty. The proposed method explicitly incorporates all the available information associated with a process model characterized by varying degrees of uncertainty, as well as available sensor measurements of certain physicochemical quantities. Based on the above information, a reduced-order soft sensor is designed enabling the reliable reconstruction of pollutant concentration profiles in complex biodegradation systems that can not be always achieved due to physical and/or technical limitations associated with current sensor technology. The option of using the aforementioned approach to compute toxic load and persistence indexes on the basis of the reconstructed concentration profiles is also pursued. Finally, the performance of the proposed method is evaluated in two illustrative environmental hazard assessment case studies.
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Affiliation(s)
- Nikolaos Kazantzis
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609-2280, USA,
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30
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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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31
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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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32
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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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33
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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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34
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Petiot E, El-Wajgali A, Esteban G, Gény C, Pinton H, Marc A. Real-time monitoring of adherent Vero cell density and apoptosis in bioreactor processes. Cytotechnology 2012; 64:429-41. [PMID: 22367019 DOI: 10.1007/s10616-011-9421-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Accepted: 12/16/2011] [Indexed: 10/28/2022] Open
Abstract
This study proposes an easy to use in situ device, based on multi-frequency permittivity measurements, to monitor the growth and death of attached Vero cells cultivated on microporous microcarriers, without any cell sampling. Vero cell densities were on-line quantified up to 10(6) cell mL(-1). Some parameters which could potentially impact Vero cell morphological and physiological states were assessed through different culture operating conditions, such as media formulation or medium feed-harvest during cell growth phase. A new method of in situ cell death detection with dielectric spectroscopy was also successfully implemented. Thus, through permittivity frequency scanning, major rises of the apoptotic cell population in bioreactor cultures were detected by monitoring the characteristic frequency of the cell population, f(c), which is one of the culture dielectric parameters. Both cell density quantification and cell apoptosis detection are strategic information in cell-based production processes as they are involved in major events of the process, such as scale-up or choice of the viral infection conditions. This new application of dielectric spectroscopy to adherent cell culture processes makes it a very promising tool for risk-mitigation strategy in industrial processes. Therefore, our results contribute to the development of Process Analytical Technology in cell-based industrial processes.
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Affiliation(s)
- Emma Petiot
- Laboratoire Réactions et Génie des Procédés, UPR CNRS 3349, Nancy-Université, 2 avenue de la Forêt de Haye, 54505, Vandoeuvre-lès-Nancy Cedex, France,
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35
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The Choice of Suitable Online Analytical Techniques and Data Processing for Monitoring of Bioprocesses. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2012. [DOI: 10.1007/10_2012_175] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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36
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Dowd JE, Jubb A, Kwok KE, Piret JM. Optimization and control of perfusion cultures using a viable cell probe and cell specific perfusion rates. Cytotechnology 2011; 42:35-45. [PMID: 19002926 DOI: 10.1023/a:1026192228471] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Consistent perfusion culture production requires reliable cell retention and control of feed rates. An on-line cell probe based on capacitance was used to assay viable biomass concentrations. A constant cell specific perfusion rate controlled medium feed rates with a bioreactor cell concentration of approximately 5 x 10(6) cells mL(-1). Perfusion feeding was automatically adjusted based on the cell concentration signal from the on-line biomass sensor. Cell specific perfusion rates were varied over a range of 0.05 to 0.4 nL cell(-1) day(-1). Pseudo-steady-state bioreactor indices (concentrations, cellular rates and yields) were correlated to cell specific perfusion rates investigated to maximize recombinant protein production from a Chinese hamster ovary cell line. The tissue-type plasminogen activator concentration was maximized ( approximately 40 mg L(-1)) at 0.2 nL cell(-1) day(-1). The volumetric protein productivity ( approximately 60 mg L(-1) day(-1) was maximized above 0.3 nL cell(-1) day(-1). The use of cell specific perfusion rates provided a straightforward basis for controlling, modeling and optimizing perfusion cultures.
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Affiliation(s)
- Jason E Dowd
- Biotechnology Laboratory, University of British Columbia, Vancouver, BC, Canada
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37
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Justice C, Brix A, Freimark D, Kraume M, Pfromm P, Eichenmueller B, Czermak P. Process control in cell culture technology using dielectric spectroscopy. Biotechnol Adv 2011; 29:391-401. [DOI: 10.1016/j.biotechadv.2011.03.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 03/04/2011] [Accepted: 03/06/2011] [Indexed: 10/18/2022]
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38
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Justice C, Leber J, Freimark D, Pino Grace P, Kraume M, Czermak P. Online- and offline- monitoring of stem cell expansion on microcarrier. Cytotechnology 2011; 63:325-35. [PMID: 21562973 DOI: 10.1007/s10616-011-9359-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 04/22/2011] [Indexed: 11/29/2022] Open
Abstract
In the biopharmaceutical industry, adherent growing stem cell cultures gain worldwide importance as cell products. The cultivation process of these cells, such as in stirred tank reactors or in fixed bed reactors, is highly sophisticated. Cultivations need to be monitored and controlled to guarantee product quality and to satisfy GMP requirements. With the process analytical technology (PAT) initiative, requirements regarding process monitoring and control have changed and real-time on-line monitoring tools are recommended. A tool meeting the new requirements may be the dielectric spectroscopy for online viable cell mass determination by measurement of the permittivity. To establish these tools, proper offline methods for data correlation are required. The cell number determination of adherent cells on microcarrier is difficult, as it requires cell detachment from the carrier, which highly increases the statistical error. As an offline method, a fluorescence assay based on SYBR(®)GreenI was developed allowing fast and easy total cell concentration determination without the need to detach the cells from the carrier. The assay is suitable for glass carriers used in stirred tank reactor systems or in fixed bed systems, may be suitable for different cell lines and can be applied to high sample numbers easily. The linear dependency of permittivity to cell concentration of suspended stem cells with the dielectric spectroscopy is shown for even very small cell concentrations. With this offline-method, a correlation of the cell concentration grown on carrier to the permittivity data measured by the dielectric spectroscopy was done successfully.
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Affiliation(s)
- C Justice
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstr. 14, 35390, Giessen, Germany
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Ansorge S, Lanthier S, Transfiguracion J, Henry O, Kamen A. Monitoring lentiviral vector production kinetics using online permittivity measurements. Biochem Eng J 2011. [DOI: 10.1016/j.bej.2011.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Opel CF, Li J, Amanullah A. Quantitative modeling of viable cell density, cell size, intracellular conductivity, and membrane capacitance in batch and fed-batch CHO processes using dielectric spectroscopy. Biotechnol Prog 2010; 26:1187-99. [PMID: 20730773 DOI: 10.1002/btpr.425] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dielectric spectroscopy was used to analyze typical batch and fed-batch CHO cell culture processes. Three methods of analysis (linear modeling, Cole-Cole modeling, and partial least squares regression), were used to correlate the spectroscopic data with routine biomass measurements [viable packed cell volume, viable cell concentration (VCC), cell size, and oxygen uptake rate (OUR)]. All three models predicted offline biomass measurements accurately during the growth phase of the cultures. However, during the stationary and decline phases of the cultures, the models decreased in accuracy to varying degrees. Offline cell radius measurements were unsuccessfully used to correct for the deviations from the linear model, indicating that physiological changes affecting permittivity were occurring. The beta-dispersion was analyzed using the Cole-Cole distribution parameters Deltaepsilon (magnitude of the permittivity drop), f(c) (critical frequency), and alpha (Cole-Cole parameter). Furthermore, the dielectric parameters static internal conductivity (sigma(i)) and membrane capacitance per area (C(m)) were calculated for the cultures. Finally, the relationship between permittivity, OUR, and VCC was examined, demonstrating how the definition of viability is critical when analyzing biomass online. The results indicate that the common assumptions of constant size and dielectric properties used in dielectric analysis are not always valid during later phases of cell culture processes. The findings also demonstrate that dielectric spectroscopy, while not a substitute for VCC, is a complementary measurement of viable biomass, providing useful auxiliary information about the physiological state of a culture.
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Affiliation(s)
- Cary F Opel
- Genentech, Inc., Oceanside PTD, US Biologics, Pharma Technical Development, One Antibody Way, Oceanside, CA 92056, USA.
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On-line monitoring of responses to nutrient feed additions by multi-frequency permittivity measurements in fed-batch cultivations of CHO cells. Cytotechnology 2010; 62:121-32. [PMID: 20407823 DOI: 10.1007/s10616-010-9267-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Accepted: 03/28/2010] [Indexed: 10/19/2022] Open
Abstract
Changes in the nutrient availability of mammalian cell cultures are reflected in the beta-dispersion parameter characteristic frequency (f ( C )) and the on-line dual frequency permittivity signal. Multi-frequency permittivity measurements were therefore evaluated in fed-batch cultivations of two different CHO cell lines. Similar responses to nutrient depletions and discontinuous feed additions were monitored in different cultivation phases and experimental setups. Sudden increases in permittivity and f ( C ) occurred when feed additions were conducted. A constant or declining permittivity value in combination with a decrease in f ( C ) indicated nutrient limitations. f ( C ) correlated well with changes in oxygen uptake rate when cell diameter remained constant, indicating that metabolic activity is reflected in the value of f ( C ). When significant cell size changes occurred during the cultivations, the analysis of the beta-dispersion parameters was rendered complex. For the application of our findings in other systems it will be hence required to conduct additional off-line measurements. Based on these results, it is hypothesized that multi-frequency permittivity measurements can give information on the intracellular or physiological state in fed-batch mode. Similar observations were made when using different cell lines and feeding strategies, indicating that the findings are transferable to other cell lines and systems. The results should lead to an improved understanding of routine fed-batch processes. Additional studies are, however, required to explore how these observations can be used for fed-batch process development and optimization.
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Huynh N, Kazantzis N, Wright RA. Digital condition monitoring of complex (bio)chemical reaction systems in the presence of model uncertainty: Application to environmental hazard monitoring. J Loss Prev Process Ind 2009. [DOI: 10.1016/j.jlp.2008.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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43
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Ansorge S, Esteban G, Schmid G. Multifrequency permittivity measurements enable on-line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells. Biotechnol Prog 2009; 26:272-83. [DOI: 10.1002/btpr.347] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Naciri M, Kuystermans D, Al-Rubeai M. Monitoring pH and dissolved oxygen in mammalian cell culture using optical sensors. Cytotechnology 2008; 57:245-50. [PMID: 19003181 DOI: 10.1007/s10616-008-9160-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 08/27/2008] [Indexed: 10/21/2022] Open
Abstract
Here, we have studied two parameters critical to process control in mammalian cell culture; dissolved oxygen (dO(2)) and pH, measured with fluorescent sensors thus allowing the study of the metabolic state of cells in culture without removing or damaging cells during cultivation. Two cell lines, namely, NS0 and CHO were batch-grown in 24-well plates at different serum concentrations with the sensors implemented in the bottom of each well. The data showed a good relationship between the dO(2) and pH data obtained from fluorescent probes and the growth and death characteristics of cells. The method has provided a high throughput on-line multi-parametric analysis of mammalian cell cellular activity.
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Affiliation(s)
- Mariam Naciri
- School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin, 4, Ireland,
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Cole–Cole, linear and multivariate modeling of capacitance data for on-line monitoring of biomass. Bioprocess Biosyst Eng 2008; 32:161-73. [DOI: 10.1007/s00449-008-0234-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
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Xiong ZQ, Guo MJ, Guo YX, Chu J, Zhuang YP, Zhang SL. Real-time viable-cell mass monitoring in high-cell-density fed-batch glutathione fermentation by Saccharomyces cerevisiae T65 in industrial complex medium. J Biosci Bioeng 2008; 105:409-13. [DOI: 10.1263/jbb.105.409] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 01/24/2008] [Indexed: 11/17/2022]
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Dziong D, Bagnaninchi PO, Kearney RE, Tabrizian M. Nondestructive online in vitro monitoring of pre-osteoblast cell proliferation within microporous polymer scaffolds. IEEE Trans Nanobioscience 2007; 6:249-58. [PMID: 17926784 DOI: 10.1109/tnb.2007.903486] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We present a system for the online, in vitro, nondestructive monitoring of tissue growth within microporous polymer scaffolds. The system is based on measuring the admittance of the sample over a frequency range of 10-200 MHz using an open-ended coaxial probe and impedance analyzer. The sample admittance is related to the sample complex permittivity (CP) by a quasi-static model of the probe's aperture admittance. A modified effective medium approximation is then used to relate the CP to the cell volume fraction. The change of cell volume fraction is used as a measure of tissue growth inside the scaffold. The system detected relative cell concentration differences between microporous polymer scaffolds seeded with 0.4, 0.45, 0.5, and 0.6 x 10(6) pre-osteoblast cells. In addition, the pre-osteoblast proliferation within 56 scaffolds over 14 days was recorded by the system and a concurrent DNA assay. Both techniques produced cell proliferation curves that corresponded to those found in literature. Thus, our data confirmed that the new system can assess relative cell concentration differences in microporous scaffolds enabling online nondestructive tissue growth monitoring.
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Affiliation(s)
- D Dziong
- McGill University, Montreal, QC H3A 2B4, Canada.
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Ansorge S, Esteban G, Schmid G. On-line monitoring of infected Sf-9 insect cell cultures by scanning permittivity measurements and comparison with off-line biovolume measurements. Cytotechnology 2007; 55:115-24. [PMID: 19003001 DOI: 10.1007/s10616-007-9093-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 09/01/2007] [Indexed: 10/22/2022] Open
Abstract
Two infected Sf-9 cell cultures were monitored on-line by multi-frequency permittivity measurements using the Fogale BIOMASS SYSTEM((R)) and by applying different off-line methods (CASY((R))1, Vi-CELLtrade mark, packed cell volume) to measure the biovolume and the mean diameter of the cell population. During the growth phase and the early infection phase the measured permittivity at the working frequency correlated well with the different off-line methods for the biovolume. We found a value of 0.67 pF cm(-1) permittivity per unit of total biovolume (CASY) (muL mL(-1)). After the maximum value in the permittivity was reached, i.e. when the viability of the cultures decreased significantly, we observed different time courses for the biovolume depending on the applied method. The differences were compared and could be explained by the underlying measurement principles. Furthermore, the characteristic frequency (f(C)) was calculated from the on-line scanning permittivity measurements. The f(C) may provide an indication of changes in cell diameter and membrane properties especially after infection and could also be an indicator for the onset of the virus production phase. The changes in f(C) were qualitatively explained by the underlying equation that is correlating f(C) and the properties of the cell population (cell diameter, intracellular conductivity and capacitance per membrane area).
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Affiliation(s)
- Sven Ansorge
- Pharmaceuticals Division, F. Hoffmann-La Roche AG, Pharma Research Basel, Protein Sciences, Basel, 4070, Switzerland,
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Breguet V, Gugerli R, von Stockar U, Marison IW. CHO immobilization in alginate/poly-L: -lysine microcapsules: an understanding of potential and limitations. Cytotechnology 2007; 53:81-93. [PMID: 19003193 DOI: 10.1007/s10616-007-9045-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Accepted: 01/23/2007] [Indexed: 11/30/2022] Open
Abstract
Microencapsulation offers a unique potential for high cell density, high productivity mammalian cell cultures. However, for successful exploitation there is the need for microcapsules of defined size, properties and mechanical stability. Four types of alginate/poly-L: -Lysine microcapsules, containing recombinant CHO cells, have been investigated: (a) 800 mum liquid core microcapsules, (b) 500 mum liquid core microcapsules, (c) 880 mum liquid core microcapsules with a double PLL membrane and (d) 740 mum semi-liquid core microcapsules. With encapsulated cells a reduced growth rate was observed, however this was accompanied by a 2-3 fold higher specific production rate of the recombinant protein. Interestingly, the maximal intracapsular cell concentration was only 8.7 x 10(7) cell mL(-1), corresponding to a colonization of 20% of the microcapsule volume. The low level of colonization is unlikely to be due to diffusional limitations since reduction of microcapsule size had no effect. Measurement of cell leaching and mechanical properties showed that liquid core microcapsules are not suitable for continuous long-term cultures (>1 month). By contrast semi-liquid core microcapsules were stable over long periods with a constant level of cell colonization (varphi = 3%). This indicates that the alginate in the core plays a predominant role in determining the level of microcapsule colonization. This was confirmed by experiments showing reduced growth rates of batch suspension cultures of CHO cells in medium containing dissolved alginate. Removal of this alginate would therefore be expected to increase microcapsule colonization.
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Affiliation(s)
- Véronique Breguet
- Laboratory of Biological and Chemical Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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