51
|
Meuwly F, Ruffieux PA, Kadouri A, von Stockar U. Packed-bed bioreactors for mammalian cell culture: bioprocess and biomedical applications. Biotechnol Adv 2006; 25:45-56. [PMID: 17034981 DOI: 10.1016/j.biotechadv.2006.08.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Accepted: 08/25/2006] [Indexed: 10/24/2022]
Abstract
This article describes the development history of packed-bed bioreactors (PBRs) used for the culture of mammalian cells. It further reviews the current applications of PBRs and discusses the steps forward in the development of these systems for bioprocess and biomedical applications. The latest generation of PBRs used in bioprocess applications achieve very high cell densities (>10(8) cells ml(-1)) leading to outstandingly high volumetric productivity. However, a major bottleneck of such PBRs is their relatively small volume. The current maximal volume appears to be in the range of 10 to 30 l. A scale-up of more than 10-fold would be necessary for these PBRs to be used in production processes. In biomedical applications, PBRs have proved themselves as compact bioartificial organs, but their metabolic activity declines frequently within 1 to 2 weeks of operation. A main challenge in this field is to develop cell lines that grow consistently to high cell density in vitro and maintain a stable phenotype for a minimum of 1 to 2 months. Achieving this will greatly enhance the usefulness of PBR technology in clinical practice.
Collapse
Affiliation(s)
- F Meuwly
- Serono Biotech Center, Laboratoires Serono S.A., Zone Industrielle B, CH-1809 Fenil-sur-Corsier, Switzerland
| | | | | | | |
Collapse
|
52
|
Carvell JP, Dowd JE. On-line Measurements and Control of Viable Cell Density in Cell Culture Manufacturing Processes using Radio-frequency Impedance. Cytotechnology 2006; 50:35-48. [PMID: 19003069 PMCID: PMC3475999 DOI: 10.1007/s10616-005-3974-x] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Accepted: 10/07/2005] [Indexed: 11/28/2022] Open
Abstract
In this work, radio-frequency (RF) impedance is reviewed as a method for monitoring and controlling cell culture manufacturing processes. It is clear from the many publications cited that RF Impedance is regarded as an accurate and reliable method for measuring the live cell bio-volume both on-line and off-line and the technology is also sutable for animal cells in suspension, attached to micro-carriers or immobilized in fixed beds. In cGMP production, RF Impedance is being used in three main areas. Firstly, it is being used as a control instrument for maintaining consistent perfusion culture allowing the bioreactor to operate under optimum conditions for maximum production of recombinant proteins. In the second application it has not replaced traditional off-line live cell counting techniques but it is being used as an additional monitoring tool to check product conformance. Finally, RF Impedance is being used to monitor the concentration of live cells immobilized on micro-carriers or packed beds in cGMP processes where traditional off-line live cell counting methods are inaccurate or impossible to perform.
Collapse
|
53
|
Meuwly F, Papp F, Ruffieux PA, Bernard AR, Kadouri A, von Stockar U. Use of glucose consumption rate (GCR) as a tool to monitor and control animal cell production processes in packed-bed bioreactors. J Biotechnol 2006; 122:122-9. [PMID: 16153735 DOI: 10.1016/j.jbiotec.2005.08.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Revised: 07/20/2005] [Accepted: 08/04/2005] [Indexed: 11/20/2022]
Abstract
For animal cell cultures growing in packed-bed bioreactors where cell number cannot be determined directly, there is a clear need to use indirect methods that are not based on cell counts in order to monitor and control the process. One option is to use the glucose consumption rate (GCR) of the culture as an indirect measure to monitor the process in bioreactors. This study was done on a packed-bed bioreactor process using recombinant CHO cells cultured on Fibra-Cel disk carriers in perfusion mode at high cell densities. A key step in the process is the switch of the process from the cell growth phase to the production phase triggered by a reduction of the temperature. In this system, we have used a GCR value of 300 g of glucose per kilogram of disks per day as a criterion for the switch. This paper will present results obtained in routine operations for the monitoring and control of an industrial process at pilot-scale. The process operated with this GCR-based strategy yielded consistent, reproducible process performance across numerous bioreactor runs performed on multiple production sites.
Collapse
Affiliation(s)
- F Meuwly
- Serono Biotech Center, Laboratoires Serono SA, Zone Industrielle B, Fenil-sur-Corsier, Switzerland
| | | | | | | | | | | |
Collapse
|
54
|
Abstract
The development of a fully automated on-line monitoring and control system is very important in bioprocesses. One of the most important parameters in these processes is biomass. This review discusses different methods for biomass quantification. A general definition of biomass and biovolume are presented. Interesting concepts about active but not culturable cells considerations are included as well as concepts that must be taken into account when selecting biomass quantification technology. Chemical methods have had few applications in biomass measurement to date; however, bioluminescence can selectively enumerate viable cells. Photometric methods including fluorescence and scattered light measurements are presented. Reference methods including dry and wet weight, viable counts and direct counts are discussed, as well as the physical methods of flow cytometry, impedancimetric and dielectric techniques.
Collapse
Affiliation(s)
- R E Madrid
- Departamento de Bioingeniería, FACET/INSIBIO, Universidad Nacional de Tucumán, Consejo Nacional de Investigaciones Científicas y Técnicas, Tucuman, Argentina.
| | | |
Collapse
|
55
|
Kacmar J, Srienc F. Dynamics of single cell property distributions in Chinese hamster ovary cell cultures monitored and controlled with automated flow cytometry. J Biotechnol 2005; 120:410-20. [PMID: 16144728 DOI: 10.1016/j.jbiotec.2005.06.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 06/06/2005] [Accepted: 06/21/2005] [Indexed: 11/19/2022]
Abstract
Two important variables that are often not measured online in Chinese hamster ovary (CHO) cell cultures are cell number concentration and culture viability. We have developed an automated flow cytometry system that measured the cell number concentration, single cell viability based on propidium iodide (PI) exclusion, and single cell light scattering from bioreactor samples every 30 min. The bioreactor was monitored during batch growth, and then the cell number concentration was controlled at a set point during cytostat operation. NH(4)Cl was added during steady state operation in cytostat mode to monitor the transient cell population response to adverse growth conditions. The automated measurements correlated well to cell concentration and viability determined manually using a hemacytometer. The described system provides a method to study mammalian cell culture physiology and dynamics in great detail. It presents a new method for the monitoring and control of animal cell culture.
Collapse
Affiliation(s)
- James Kacmar
- Department of Chemical Engineering and Materials Science, University of Minnesota, 151 Amundson Hall, 421 Washington Avenue S.E., Minneapolis, MN 55455-0312, USA
| | | |
Collapse
|
56
|
Gmati D, Chen J, Jolicoeur M. Development of a small-scale bioreactor: application to in vivo NMR measurement. Biotechnol Bioeng 2005; 89:138-47. [PMID: 15584028 DOI: 10.1002/bit.20293] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A perfused bioreactor allowing in vivo NMR measurement was developed and validated for Eschscholtzia californica cells. The bioreactor was made of a 10-mm NMR tube. NMR measurement of the signal-to-noise ratio was optimized using a sedimented compact bed of cells that were retained in the bioreactor by a supporting filter. Liquid medium flow through the cell bed was characterized from a mass balance on oxygen and a dispersive hydrodynamic model. Cell bed oxygen demand for 4 h perfusion required a minimal medium flow rate of 0.8 mL/min. Residence time distribution assays at 0.8-2.6 mL/min suggest that the cells are subjected to a uniform nutrient environment along the cell bed. Cell integrity was maintained for all culture conditions since the release of intracellular esterases was not significant even after 4 h of perfusion. In vivo NMR was performed for (31)P NMR and the spectrum can be recorded after only 10 min of spectral accumulation (500 scans) with peaks identified as G-6P, F-6P, cytoplasmic Pi, vacuolar Pi, ATP(gamma) and ADP(beta), ATP(alpha) and ADP(alpha), NADP and NDPG, NDPG and ATP(beta). Cell viability was shown to be maintained as (31)P chemical shifts were constant with time for all the identified nuclei, thus suggesting constant intracellular pH.
Collapse
Affiliation(s)
- Dorra Gmati
- Bio-P2 Research Unit, Department of Chemical Engineering, Ecole Polytechnique de Montréal, P.O. Box 6079, Centreville Station, Montréal, Québec, Canada
| | | | | |
Collapse
|
57
|
Meuwly F, von Stockar U, Kadouri A. Optimization of the medium perfusion rate in a packed-bed bioreactor charged with CHO cells. Cytotechnology 2005; 46:37-47. [PMID: 19003257 DOI: 10.1007/s10616-005-2105-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2004] [Accepted: 02/08/2005] [Indexed: 11/26/2022] Open
Abstract
In the present study, the optimal medium perfusion rate to be used for the continuous culture of a recombinant CHO cell line in a packed-bed bioreactor made of Fibra-Cel((R)) disk carriers was determined. A first-generation process had originally been designed with a high perfusion rate, in order to rapidly produce material for pre-clinical and early clinical trials. It was originally operated with a perfusion of 2.6 vvd during production phase in order to supply the high cell density (2.5x10(7) cell ml(-1) of packed-bed) with sufficient fresh medium. In order to improve the economics of this process, a reduction of the medium perfusion rate by -25% and -50% was investigated at small-scale. The best option was then implemented at pilot scale in order to further produce material for clinical trials with an improved second-generation process. With a -25% reduction of the perfusion rate, the volumetric productivity was maintained compared to the first-generation process, but a -30% loss of productivity was obtained when the medium perfusion rate was further reduced to -50% of its original level. The protein quality under reduced perfusion rate conditions was analyzed for purity, N-glycan sialylation level, abundance of dimers or aggregates, and showed that the quality of the final drug substance was comparable to that obtained in reference conditions. Finally, a reduction of -25% medium perfusion was implemented at pilot scale in the second-generation process, which enabled to maintain the same productivity and the same quality of the molecule, while reducing costs of media, material and manpower of the production process. For industrial applications, it is recommended to test whether and how far the perfusion rate can be decreased during the production phase - provided that the product is not sensitive to residence time - with the benefits of reduced cost of goods and to simplify manufacturing operations.
Collapse
Affiliation(s)
- F Meuwly
- Laboratoires Serono S.A., Zone Industrielle B , Serono Biotech Center, CH-1809, Fenil-sur-Corsier, Switzerland
| | | | | |
Collapse
|
58
|
Bagnaninchi PO, Dikeakos M, Veres T, Tabrizian M. Complex permittivity measurement as a new noninvasive tool for monitoring in vitro tissue engineering and cell signature through the detection of cell proliferation, differentiation, and pretissue formation. IEEE Trans Nanobioscience 2005; 3:243-50. [PMID: 15631135 DOI: 10.1109/tnb.2004.837901] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In in vitro tissue engineering, microporous scaffolds are commonly used to promote cell proliferation and differentiation in three-dimensional structures. Classic measurement methods are particularly time consuming, difficult to handle, and destructive. In this study, a new nondestructive method based on complex permittivity measurement (CPM) is proposed to monitor and track the osteoblast and macrophage differentiation through their morphological variation upon cell attachment and proliferation inside the microporous scaffolds. CPM is performed using a vector network analyzer and a dielectric probe under sterile conditions in a laminar-flow hood. A suitable effective medium approximation (EMA) is applied to fit the data in order to extract the parameters of the different constituents. Our data show that the EMA depolarization factor can be monitored to assess the variation of cell morphology characterizing cell attachment. Discrimination between two batches of scaffolds seeded, respectively, with 2 million and 1 million osteoblast cells is possible; the ratio of their CPM-derived cell volume fractions is in agreement with the ratio of their cell seeding numbers. In addition, cell proliferation inside scaffolds seeded with osteoblasts cultured in alpha minimum essential medium and inside scaffolds seeded with osteoblasts cultured in alpha minimum essential medium supplemented to induce the formation of extracellular matrix is monitored via CPM over several days. CPM-determined cell volume fraction is compared to DNA assay cell counts. Extracellular matrix formation and cell presence was confirmed by scanning electron microscopy. A set of three signature parameters (epsilon'mem, epsilon'cyt, kappa'cyt) characteristic of cell line is extracted from CPM. Distinct signatures are recorded for osteoblasts and macrophages, thus confirming the ability of CPM to discriminate between different cell types. This study demonstrates the potential of CPM as a diagnostic tool to monitor quickly and noninvasively cell growth and differentiation inside microporous scaffolds. Our findings suggest that the use of CPM could be extended to many biomedical applications, such as drug detection and automation of tissue and bacterial cultures in bioreactors.
Collapse
|
59
|
Kazantzis N, Huynh N, Wright RA. Nonlinear observer design for the slow states of a singularly perturbed system. Comput Chem Eng 2005. [DOI: 10.1016/j.compchemeng.2004.09.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
60
|
Gorenflo VM, Chow VS, Chou C, Piret JM. Optical analysis of perfusion bioreactor cell concentration in an acoustic separator. Biotechnol Bioeng 2005; 92:514-8. [PMID: 16155953 DOI: 10.1002/bit.20693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Automated monitoring of cell concentration in perfusion bioprocesses facilitates the maintenance of constant cell specific perfusion rates. However, most on-line measuring devices are relatively complex and foul as the culture progresses. A simple external optical sensor was developed using the transparent glass walls of acoustic separators for automated optical analysis of their contents. For each measurement, the separator was filled by an automated pumping system with triplicate representative bioreactor samples that were optically analyzed and the device returned to perfusion operation within approximately 1 or 2 min. Chinese hamster ovary cell concentrations, ranging from 5 x 10(5) to 2 x 10(7) cells/mL, were highly correlated (R(2) = 0.99) with the 90 degrees scattered light response. Since the device was operated externally, it did not complicate bioreactor sterilization or cleaning. Viability was not optically analyzed, but this information was not required between manual samples of a properly operated perfusion process. Using single-point recalibration based on routine off-line samples, this external optical system remained effective during a 4-month perfusion run, thus providing a non-invasive and easily maintained on-line cell concentration monitoring system to improve the control of perfusion bioreactors.
Collapse
Affiliation(s)
- Volker M Gorenflo
- Michael Smith Laboratories, 2185 East Mall, University of British Columbia, Vancouver, British Columbia, Canada.
| | | | | | | |
Collapse
|
61
|
Bagnaninchi PO, Dikeakos M, Veres T, Tabrizian M. Towards on-line monitoring of cell growth in microporous scaffolds: Utilization and interpretation of complex permittivity measurements. Biotechnol Bioeng 2003; 84:343-50. [PMID: 12968288 DOI: 10.1002/bit.10770] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Here we demonstrate the ability to characterize microporous scaffolds and evaluate cell concentration variation via the utilization and interpretation of complex permittivity measurements (CP), a direct and nondestructive method. Polymer-based microporous scaffolds are of importance to tissue engineering, particularly in the promotion of cell adhesion, proliferation, and differentiation in predefined shapes. Chitosan gel scaffolds were seeded with increasing concentrations of macrophages to simulate cell growth. Complex permittivity measurements were performed using a dielectric probe and a vector network analyzer over a frequency ranging from 200 MHz to 2 GHz. An effective medium theory was applied to interpret the data obtained; respectively, Looyenga and Maxwell-Wagner-Hanai functions were used to retrieve the porosity and the variation of the cell concentration from the CP measurements. Calculated porosities were in agreement with experimental evaluation-porosity ranged from 81-96%. Changes in cell concentration inside the scaffolds upon injection of differing cell concentrations into the scaffold were detected distinguishably. Variations resulting from the cumulative injection of 400-1800 microL of 10(6) cells/mL solution into the scaffold were monitored. Results suggest that CP measurements in combination with an appropriate effective medium approximation can enable on-line monitoring of cell growth within scaffolds.
Collapse
Affiliation(s)
- Pierre-Olivier Bagnaninchi
- Department of Biomedical Engineering, McGill University, 3775 University Street, Montreal, Quebec H3A 2B4, Canada
| | | | | | | |
Collapse
|
62
|
Cannizzaro C, Gügerli R, Marison I, von Stockar U. On-line biomass monitoring of CHO perfusion culture with scanning dielectric spectroscopy. Biotechnol Bioeng 2003; 84:597-610. [PMID: 14574694 DOI: 10.1002/bit.10809] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this work, dielectric spectroscopy was used to monitor two CHO perfusion culture experiments (B14 and B16). The capacitance of the cell suspension was recorded every 20 minutes over an excitation frequency range of 0.2 MHz to 10.0 MHz. A phase plot of the capacitance at a low excitation frequency vs. the value at a higher frequency proved to be an accurate indicator of the major transition points of the culture, i.e., maximum cell viability, end of lactate consumption, point of zero viability. For both experiments, the capacitance signal correlated very well (R(2) >0.98) with viable cell number up to concentrations of 1 x 10(7) cells/mL. Visual observation of the capacitance spectra indicated that changes in the capacitance relative to frequency were related to the cellular morphology. A multivariate model was developed using off-line data that could predict the median cell diameter within a single experiment (B14) with an error of 0.34 microm (2%). Upon extension to a subsequent experiment (B16), the predicted error was 1.18 microm (9%).
Collapse
Affiliation(s)
- Christopher Cannizzaro
- Laboratory of Chemical and Biochemical Engineering, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
| | | | | | | |
Collapse
|