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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Neuss A, von Vegesack N, Liepelt R, Büchs J, Barsett Magnus J. Online monitoring of the respiration activity in 96-deep-well microtiter plate Chinese hamster ovary cultures streamlines kill curve experiments. Biotechnol Prog 2024:e3468. [PMID: 38602130 DOI: 10.1002/btpr.3468] [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: 01/26/2024] [Revised: 03/25/2024] [Accepted: 03/28/2024] [Indexed: 04/12/2024]
Abstract
Cell line generation of mammalian cells is a time-consuming and labor-intensive process, especially because of challenges in clone selection after transfection. Antibiotics are common selection agents for mammalian cells due to their simplicity of use. However, the optimal antibiotic concentration must be determined with a kill curve experiment before clone selection starts. The traditional kill curve experiments are resource-intensive and time-consuming due to necessary sampling and offline analysis effort. This study, thus, explores the potential of online monitoring the oxygen transfer rate (OTR), as a non-invasive and efficient alternative for kill curve experiments. The OTR is monitored using the Transfer-rate Online Measurement (TOM) system and the micro(μ)-scale Transfer-rate Online Measurement (μTOM) device, which was used for mammalian cells first. It could be shown that the OTR curves for both devices align perfectly, affirming consistent cultivation conditions. The μTOM device proves effective in performing kill curve experiments in 96-deep-well plates without the need for sampling and offline analysis. The streamlined approach reduces medium consumption by 95%, offering a cost-effective and time-efficient solution for kill curve experiments. The study validates the generalizability of the method by applying it to two different CHO cell lines (CHO-K1 and sciCHO) with two antibiotics (puromycin and hygromycin B) each. In conclusion, the broad application of OTR online monitoring for CHO cell cultures in 96-deep-well plates is highlighted. The μTOM device proves as a valuable tool for high-throughput experiments, paving the way for diverse applications, such as media and clone screening, cytotoxicity tests, and scale-up experiments.
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Affiliation(s)
- Anne Neuss
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Nele von Vegesack
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Raoul Liepelt
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Jochen Büchs
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
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3
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Nikita S, Mishra S, Gupta K, Runkana V, Gomes J, Rathore AS. Advances in bioreactor control for production of biotherapeutic products. Biotechnol Bioeng 2023; 120:1189-1214. [PMID: 36760086 DOI: 10.1002/bit.28346] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/08/2023] [Accepted: 02/08/2023] [Indexed: 02/11/2023]
Abstract
Advanced control strategies are well established in chemical, pharmaceutical, and food processing industries. Over the past decade, the application of these strategies is being explored for control of bioreactors for manufacturing of biotherapeutics. Most of the industrial bioreactor control strategies apply classical control techniques, with the control system designed for the facility at hand. However, with the recent progress in sensors, machinery, and industrial internet of things, and advancements in deeper understanding of the biological processes, coupled with the requirement of flexible production, the need to develop a robust and advanced process control system that can ease process intensification has emerged. This has further fuelled the development of advanced monitoring approaches, modeling techniques, process analytical technologies, and soft sensors. It is seen that proper application of these concepts can significantly improve bioreactor process performance, productivity, and reproducibility. This review is on the recent advancements in bioreactor control and its related aspects along with the associated challenges. This study also offers an insight into the future prospects for development of control strategies that can be designed for industrial-scale production of biotherapeutic products.
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Affiliation(s)
- Saxena Nikita
- Department of Chemical Engineering, DBT Centre of Excellence for Biopharmaceutical Technology, Indian Institute of Technology, Hauz Khas, Delhi, India
| | - Somesh Mishra
- Department of Chemical Engineering, DBT Centre of Excellence for Biopharmaceutical Technology, Indian Institute of Technology, Hauz Khas, Delhi, India
| | - Keshari Gupta
- TCS Research, Tata Consultancy Services Limited, Pune, India
| | | | - James Gomes
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, Delhi, India
| | - Anurag S Rathore
- Department of Chemical Engineering, DBT Centre of Excellence for Biopharmaceutical Technology, Indian Institute of Technology, Hauz Khas, Delhi, India
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4
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Fedi A, Vitale C, Giannoni P, Caluori G, Marrella A. Biosensors to Monitor Cell Activity in 3D Hydrogel-Based Tissue Models. SENSORS (BASEL, SWITZERLAND) 2022; 22:1517. [PMID: 35214418 PMCID: PMC8879987 DOI: 10.3390/s22041517] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/06/2022] [Accepted: 02/09/2022] [Indexed: 12/13/2022]
Abstract
Three-dimensional (3D) culture models have gained relevant interest in tissue engineering and drug discovery owing to their suitability to reproduce in vitro some key aspects of human tissues and to provide predictive information for in vivo tests. In this context, the use of hydrogels as artificial extracellular matrices is of paramount relevance, since they allow closer recapitulation of (patho)physiological features of human tissues. However, most of the analyses aimed at characterizing these models are based on time-consuming and endpoint assays, which can provide only static and limited data on cellular behavior. On the other hand, biosensing systems could be adopted to measure on-line cellular activity, as currently performed in bi-dimensional, i.e., monolayer, cell culture systems; however, their translation and integration within 3D hydrogel-based systems is not straight forward, due to the geometry and materials properties of these advanced cell culturing approaches. Therefore, researchers have adopted different strategies, through the development of biochemical, electrochemical and optical sensors, but challenges still remain in employing these devices. In this review, after examining recent advances in adapting existing biosensors from traditional cell monolayers to polymeric 3D cells cultures, we will focus on novel designs and outcomes of a range of biosensors specifically developed to provide real-time analysis of hydrogel-based cultures.
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Affiliation(s)
- Arianna Fedi
- National Research Council of Italy, Institute of Electronics, Computer and Telecommunication Engineering (IEIIT), 16149 Genoa, Italy; (A.F.); (C.V.)
- Department of Computer Science, Bioengineering, Robotics and Systems Engineering (DIBRIS), University of Genoa, 16126 Genoa, Italy
| | - Chiara Vitale
- National Research Council of Italy, Institute of Electronics, Computer and Telecommunication Engineering (IEIIT), 16149 Genoa, Italy; (A.F.); (C.V.)
- Department of Experimental Medicine (DIMES), University of Genoa, 16132 Genoa, Italy;
| | - Paolo Giannoni
- Department of Experimental Medicine (DIMES), University of Genoa, 16132 Genoa, Italy;
| | - Guido Caluori
- IHU LIRYC, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, 33600 Pessac, France;
- INSERM UMR 1045, Cardiothoracic Research Center of Bordeaux, University of Bordeaux, 33600 Pessac, France
| | - Alessandra Marrella
- National Research Council of Italy, Institute of Electronics, Computer and Telecommunication Engineering (IEIIT), 16149 Genoa, Italy; (A.F.); (C.V.)
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5
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Modern Sensor Tools and Techniques for Monitoring, Controlling, and Improving Cell Culture Processes. Processes (Basel) 2022. [DOI: 10.3390/pr10020189] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The growing biopharmaceutical industry has reached a level of maturity that allows for the monitoring of numerous key variables for both process characterization and outcome predictions. Sensors were historically used in order to maintain an optimal environment within the reactor to optimize process performance. However, technological innovation has pushed towards on-line in situ continuous monitoring of quality attributes that could previously only be estimated off-line. These new sensing technologies when coupled with software models have shown promise for unique fingerprinting, smart process control, outcome improvement, and prediction. All this can be done without requiring invasive sampling or intervention on the system. In this paper, the state-of-the-art sensing technologies and their applications in the context of cell culture monitoring are reviewed with emphasis on the coming push towards industry 4.0 and smart manufacturing within the biopharmaceutical sector. Additionally, perspectives as to how this can be leveraged to improve both understanding and outcomes of cell culture processes are discussed.
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6
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Ihling N, Munkler LP, Berg C, Reichenbächer B, Wirth J, Lang D, Wagner R, Büchs J. Time-Resolved Monitoring of the Oxygen Transfer Rate of Chinese Hamster Ovary Cells Provides Insights Into Culture Behavior in Shake Flasks. Front Bioeng Biotechnol 2021; 9:725498. [PMID: 34513814 PMCID: PMC8423908 DOI: 10.3389/fbioe.2021.725498] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/12/2021] [Indexed: 11/13/2022] Open
Abstract
Cultivations of mammalian cells are routinely conducted in shake flasks. In contrast to instrumented bioreactors, reliable options for non-invasive, time-resolved monitoring of the culture status in shake flasks are lacking. The Respiration Activity Monitoring Respiration Activity Monitoring System system was used to determine the oxygen transfer rate (OTR) in shake flasks. It was proven that the OTR could be regarded as equal to the oxygen uptake rate as the change of the dissolved oxygen concentration in the liquid phase over time was negligibly small. Thus, monitoring the oxygen transfer rate (OTR) was used to increase the information content from shake flask experiments. The OTR of a Chinese hamster ovary cell line was monitored by applying electrochemical sensors. Glass flasks stoppered with cotton plugs and polycarbonate flasks stoppered with vent-caps were compared in terms of mass transfer characteristics and culture behavior. Similar mass transfer resistances were determined for both sterile closures. The OTR was found to be well reproducible within one experiment (standard deviation <10%). It correlated with changes in cell viability and depletion of carbon sources, thus, giving more profound insights into the cultivation process. Culture behavior in glass and polycarbonate flasks was identical. Monitoring of the OTR was applied to a second culture medium. Media differed in the maximum OTR reached during cultivation and in the time when all carbon sources were depleted. By applying non-invasive, parallelized, time-resolved monitoring of the OTR, the information content and amount of data from shake flask experiments was significantly increased compared to manual sampling and offline analysis. The potential of the technology for early-stage process development was demonstrated.
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Affiliation(s)
- Nina Ihling
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | | | - Christoph Berg
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | | | | | | | | | - Jochen Büchs
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
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7
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Steinegger A, Wolfbeis OS, Borisov SM. Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications. Chem Rev 2020; 120:12357-12489. [PMID: 33147405 PMCID: PMC7705895 DOI: 10.1021/acs.chemrev.0c00451] [Citation(s) in RCA: 182] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Indexed: 12/13/2022]
Abstract
This is the first comprehensive review on methods and materials for use in optical sensing of pH values and on applications of such sensors. The Review starts with an introduction that contains subsections on the definition of the pH value, a brief look back on optical methods for sensing of pH, on the effects of ionic strength on pH values and pKa values, on the selectivity, sensitivity, precision, dynamic ranges, and temperature dependence of such sensors. Commonly used optical sensing schemes are covered in a next main chapter, with subsections on methods based on absorptiometry, reflectometry, luminescence, refractive index, surface plasmon resonance, photonic crystals, turbidity, mechanical displacement, interferometry, and solvatochromism. This is followed by sections on absorptiometric and luminescent molecular probes for use pH in sensors. Further large sections cover polymeric hosts and supports, and methods for immobilization of indicator dyes. Further and more specific sections summarize the state of the art in materials with dual functionality (indicator and host), nanomaterials, sensors based on upconversion and 2-photon absorption, multiparameter sensors, imaging, and sensors for extreme pH values. A chapter on the many sensing formats has subsections on planar, fiber optic, evanescent wave, refractive index, surface plasmon resonance and holography based sensor designs, and on distributed sensing. Another section summarizes selected applications in areas, such as medicine, biology, oceanography, bioprocess monitoring, corrosion studies, on the use of pH sensors as transducers in biosensors and chemical sensors, and their integration into flow-injection analyzers, microfluidic devices, and lab-on-a-chip systems. An extra section is devoted to current challenges, with subsections on challenges of general nature and those of specific nature. A concluding section gives an outlook on potential future trends and perspectives.
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Affiliation(s)
- Andreas Steinegger
- Institute
of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Otto S. Wolfbeis
- Institute
of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, D-93040 Regensburg, Germany
| | - Sergey M. Borisov
- Institute
of Analytical Chemistry and Food Chemistry, Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
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8
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Moldero IL, Chandra A, Cavo M, Mota C, Kapsokalyvas D, Gigli G, Moroni L, Del Mercato LL. Probing the pH Microenvironment of Mesenchymal Stromal Cell Cultures on Additive-Manufactured Scaffolds. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002258. [PMID: 32656904 DOI: 10.1002/smll.202002258] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/05/2020] [Indexed: 05/22/2023]
Abstract
Despite numerous advances in the field of tissue engineering and regenerative medicine, monitoring the formation of tissue regeneration and its metabolic variations during culture is still a challenge and mostly limited to bulk volumetric assays. Here, a simple method of adding capsules-based optical sensors in cell-seeded 3D scaffolds is presented and the potential of these sensors to monitor the pH changes in space and time during cell growth is demonstrated. It is shown that the pH decreased over time in the 3D scaffolds, with a more prominent decrease at the edges of the scaffolds. Moreover, the pH change is higher in 3D scaffolds compared to monolayered 2D cell cultures. The results suggest that this system, composed by capsules-based optical sensors and 3D scaffolds with predefined geometry and pore architecture network, can be a suitable platform for monitoring pH variations during 3D cell growth and tissue formation. This is particularly relevant for the investigation of 3D cellular microenvironment alterations occurring both during physiological processes, such as tissue regeneration, and pathological processes, such as cancer evolution.
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Affiliation(s)
- Ivan Lorenzo Moldero
- Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, 6229ER, The Netherlands
| | - Anil Chandra
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
| | - Marta Cavo
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
| | - Carlos Mota
- Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, 6229ER, The Netherlands
| | - Dimitrios Kapsokalyvas
- Department of Molecular Cell Biology, Maastricht University Medical Center, UNS 50, Maastricht, 6229ER, The Netherlands
| | - Giuseppe Gigli
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, via Arnesano, Lecce, 73100, Italy
| | - Lorenzo Moroni
- Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, 6229ER, The Netherlands
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
| | - Loretta L Del Mercato
- Institute of Nanotechnology, National Research Council (CNR-NANOTEC), Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
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9
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García-Fernández C, López-Fernández A, Borrós S, Lecina M, Vives J. Strategies for large-scale expansion of clinical-grade human multipotent mesenchymal stromal cells. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107601] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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10
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Chopda VR, Holzberg T, Ge X, Folio B, Wong L, Tolosa M, Kostov Y, Tolosa L, Rao G. Real-time dissolved carbon dioxide monitoring II: Surface aeration intensification for efficient CO 2 removal in shake flasks and mini-bioreactors leads to superior growth and recombinant protein yields. Biotechnol Bioeng 2020; 117:992-998. [PMID: 31840800 PMCID: PMC7078866 DOI: 10.1002/bit.27252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 01/07/2023]
Abstract
Mass transfer is known to play a critical role in bioprocess performance and henceforth monitoring dissolved O2 (DO) and dissolved CO2 (dCO2 ) is of paramount importance. At bioreactor level these parameters can be monitored online and can be controlled by sparging air/oxygen or stirrer speed. However, traditional small-scale systems such as shake flasks lack real time monitoring and also employ only surface aeration with additional diffusion limitations imposed by the culture plug. Here we present implementation of intensifying surface aeration by sparging air in the headspace of the reaction vessel and real-time monitoring of DO and dCO2 in the bioprocesses to evaluate the impact of intensified surface aeration. We observed that sparging air in the headspace allowed us to keep dCO2 at low level, which significantly improved not only biomass growth but also protein yield. We expect that implementing such controlled smart shake flasks can minimize the process development gap which currently exists in shake flask level and bioreactor level results.
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Affiliation(s)
- Viki R. Chopda
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Timothy Holzberg
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Xudong Ge
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Brandon Folio
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Lynn Wong
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Michael Tolosa
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Yordan Kostov
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Leah Tolosa
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
| | - Govind Rao
- Department of Chemical, Biochemical and Environmental EngineeringCenter for Advanced Sensor Technology, University of MarylandBaltimoreMaryland
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11
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Rafferty C, O'Mahony J, Burgoyne B, Rea R, Balss KM, Latshaw DC. Raman spectroscopy as a method to replace off‐line pH during mammalian cell culture processes. Biotechnol Bioeng 2019; 117:146-156. [DOI: 10.1002/bit.27197] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 09/11/2019] [Accepted: 10/15/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Carl Rafferty
- Janssen Sciences Ireland UC, BioTherapeutic Development Cork Ireland
- Cork Institute of Technology, Biological Sciences Cork Ireland
| | - Jim O'Mahony
- Cork Institute of Technology, Biological Sciences Cork Ireland
| | - Barbara Burgoyne
- Janssen Sciences Ireland UC, Product Quality Management Cork Ireland
| | - Rosemary Rea
- Cork Institute of Technology, Biological Sciences Cork Ireland
| | - Karin M. Balss
- Janssen Pharmaceutical Companies of Johnson and Johnson, Process Science and Advanced Analytics New Jersey
| | - David C. Latshaw
- Janssen Pharmaceutical Companies of Johnson and Johnson, Process Science and Advanced Analytics New Jersey
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12
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Deegan AJ, Hendrikson WJ, El Haj AJ, Rouwkema J, Yang Y. Regulation of endothelial cell arrangements within hMSC - HUVEC co-cultured aggregates. Biomed J 2019; 42:166-177. [PMID: 31466710 PMCID: PMC6717755 DOI: 10.1016/j.bj.2019.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 11/25/2018] [Accepted: 01/14/2019] [Indexed: 12/12/2022] Open
Abstract
Background Micro-mass culturing or cellular aggregation is an effective method used to form mineralised bone tissue. Poor core cell viability, however, is often an impeding characteristic of large micro-mass cultures, and equally for large tissue-engineered bone grafts. Because of this, efforts are being made to enhance large graft perfusion, often through pre-vascularisation, which involves the co-culture of endothelial cells and bone cells or stem cells. Methods This study investigated the effects of different aggregation techniques and culture conditions on endothelial cell arrangements in mesenchymal stem cell and human umbilical vein endothelial cell co-cultured aggregates when endothelial cells constituted just 5%. Two different cellular aggregation techniques, i.e. suspension culture aggregation and pellet culture aggregation, were applied alongside two subsequent culturing techniques, i.e. hydrostatic loading and static culturing. Endothelial cell arrangements were assessed under such conditions to indicate potential pre-vascularisation. Results Our study found that the suspension culture aggregates cultured under hydrostatic loading offered the best environment for enhanced endothelial cell regional arrangements, closely followed by the pellet culture aggregates cultured under hydrostatic loading, the suspension culture aggregates cultured under static conditions, and the pellet culture aggregates cultured under static conditions. Conclusions The combination of particular aggregation techniques with dynamic culturing conditions appeared to have a synergistic effect on the cellular arrangements within the co-cultured aggregates.
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Affiliation(s)
- Anthony J Deegan
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Stoke-on-Trent, United Kingdom
| | - Wim J Hendrikson
- Department of Tissue Regeneration, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, AE, the Netherlands
| | - Alicia J El Haj
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Stoke-on-Trent, United Kingdom
| | - Jeroen Rouwkema
- Department of Biomechanical Engineering, Technical Medical Centre, University of Twente, Enschede, the Netherlands
| | - Ying Yang
- Institute for Science and Technology in Medicine, School of Medicine, Keele University, Stoke-on-Trent, United Kingdom.
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13
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Chemometric identification of canonical metabolites linking critical process parameters to monoclonal antibody production during bioprocess development. Chin J Chem Eng 2019. [DOI: 10.1016/j.cjche.2018.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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14
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You YH, Biswas A, Nagaraja AT, Hwang JH, Coté GL, McShane MJ. Multidomain-Based Responsive Materials with Dual-Mode Optical Readouts. ACS APPLIED MATERIALS & INTERFACES 2019; 11:14286-14295. [PMID: 30908908 DOI: 10.1021/acsami.8b21861] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Responsive materials designed to generate signals for both surface-enhanced Raman spectroscopy (SERS) and phosphorescence lifetime-"dual-mode"-measurements are described. To demonstrate this concept, we incorporated pH-sensitive and oxygen-sensitive microdomains into a single hydrogel that could be interrogated via SERS and phosphorescence lifetime, respectively. Microdomains consisted two populations of discrete microcapsules containing either (1) gold nanoparticles capped with pH-sensitive Raman molecules or (2) oxygen-sensitive benzoporphyrin phosphors. While the microdomain-embedded hydrogels presented an expected background luminescence, the pH-sensitive SERS signal was distinguishable for all tested conditions. Response characteristics of the dual sensor showed no significant difference when compared to standalone single-mode pH and oxygen sensors. In addition, the feasibility of redundant multimode sensing was proven by observing the reaction produced by glucose oxidase chemically cross-linked within the corresponding alginate matrix. Each optical mode showed a signal change proportional to glucose concentration with an opposite signal directionality. These results support the promise of micro-/nanocomposite materials to improve measurement accuracy using intrinsic multimode responses and built-in redundancy, concepts that have broad appeal in the chemical sensing and biosensing fields.
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Affiliation(s)
| | | | | | - Jin-Ha Hwang
- Department of Materials Science and Engineering , Hongik University , 121-791 Seoul , South Korea
| | - Gerard L Coté
- Center for Remote Health Technologies & Systems , Texas A&M Engineering Experiment Station , College Station , Texas 77840 , United States
| | - Michael J McShane
- Center for Remote Health Technologies & Systems , Texas A&M Engineering Experiment Station , College Station , Texas 77840 , United States
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15
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Wan X, Marsafari M, Xu P. Engineering metabolite-responsive transcriptional factors to sense small molecules in eukaryotes: current state and perspectives. Microb Cell Fact 2019; 18:61. [PMID: 30914048 PMCID: PMC6434827 DOI: 10.1186/s12934-019-1111-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 03/20/2019] [Indexed: 11/18/2022] Open
Abstract
Nature has evolved exquisite sensing mechanisms to detect cellular and environmental signals surrounding living organisms. These biosensors have been widely used to sense small molecules, detect environmental cues and diagnose disease markers. Metabolic engineers and synthetic biologists have been able to exploit metabolites-responsive transcriptional factors (MRTFs) as basic tools to rewire cell metabolism, reprogram cellular activity as well as boost cell’s productivity. This is commonly achieved by integrating sensor-actuator systems with biocatalytic functions and dynamically allocating cellular resources to drive carbon flux toward the target pathway. Up to date, most of identified MRTFs are derived from bacteria. As an endeavor to advance intelligent biomanufacturing in yeast cell factory, we will summarize the opportunities and challenges to transfer the bacteria-derived MRTFs to expand the small-molecule sensing capability in eukaryotic cells. We will discuss the design principles underlying MRTF-based biosensors in eukaryotic cells, including the choice of reliable reporters and the characterization tools to minimize background noise, strategies to tune the sensor dynamic range, sensitivity and specificity, as well as the criteria to engineer activator and repressor-based biosensors. Due to the physical separation of transcription and protein expression in eukaryotes, we argue that nuclear import/export mechanism of MRTFs across the nuclear membrane plays a critical role in regulating the MRTF sensor dynamics. Precisely-controlled MRTF response will allow us to repurpose the vast majority of transcriptional factors as molecular switches to achieve temporal or spatial gene expression in eukaryotes. Uncovering this knowledge will inform us fundamental design principles to deliver robust cell factories and enable the design of reprogrammable and predictable biological systems for intelligent biomanufacturing, smart therapeutics or precision medicine in the foreseeable future.
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Affiliation(s)
- Xia Wan
- Department of Chemical Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, 21250, USA.,Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, 430062, Hubei, China.,Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, Hubei, China
| | - Monireh Marsafari
- Department of Chemical Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, 21250, USA.,Department of Agronomy and Plant Breeding, University of Guilan, Rasht, Islamic Republic of Iran
| | - Peng Xu
- Department of Chemical Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, 21250, USA.
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16
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Bergenholm D, Liu G, Hansson D, Nielsen J. Construction of mini‐chemostats for high‐throughput strain characterization. Biotechnol Bioeng 2019; 116:1029-1038. [DOI: 10.1002/bit.26931] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 01/10/2019] [Accepted: 01/16/2019] [Indexed: 01/31/2023]
Affiliation(s)
- David Bergenholm
- Novo Nordisk Foundation Center for Biosustainability, Department of Biology and Biological EngineeringChalmers University of TechnologyGothenburg Sweden
| | - Guodong Liu
- Novo Nordisk Foundation Center for Biosustainability, Department of Biology and Biological EngineeringChalmers University of TechnologyGothenburg Sweden
| | - David Hansson
- Novo Nordisk Foundation Center for Biosustainability, Department of Biology and Biological EngineeringChalmers University of TechnologyGothenburg Sweden
| | - Jens Nielsen
- Novo Nordisk Foundation Center for Biosustainability, Department of Biology and Biological EngineeringChalmers University of TechnologyGothenburg Sweden
- Novo Nordisk Foundation Center for Biosustainability, Technical University of DenmarkHørsholm Denmark
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de Almeida Fuzeta M, de Matos Branco AD, Fernandes-Platzgummer A, da Silva CL, Cabral JMS. Addressing the Manufacturing Challenges of Cell-Based Therapies. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2019; 171:225-278. [PMID: 31844924 DOI: 10.1007/10_2019_118] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exciting developments in the cell therapy field over the last decades have led to an increasing number of clinical trials and the first cell products receiving marketing authorization. In spite of substantial progress in the field, manufacturing of cell-based therapies presents multiple challenges that need to be addressed in order to assure the development of safe, efficacious, and cost-effective cell therapies.The manufacturing process of cell-based therapies generally requires tissue collection, cell isolation, culture and expansion (upstream processing), cell harvest, separation and purification (downstream processing), and, finally, product formulation and storage. Each one of these stages presents significant challenges that have been the focus of study over the years, leading to innovative and groundbreaking technological advances, as discussed throughout this chapter.Delivery of cell-based therapies relies on defining product targets while controlling process variable impact on cellular features. Moreover, commercial viability is a critical issue that has had damaging consequences for some therapies. Implementation of cost-effectiveness measures facilitates healthy process development, potentially being able to influence end product pricing.Although cell-based therapies represent a new level in bioprocessing complexity in every manufacturing stage, they also show unprecedented levels of therapeutic potential, already radically changing the landscape of medical care.
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Affiliation(s)
- Miguel de Almeida Fuzeta
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - André Dargen de Matos Branco
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Ana Fernandes-Platzgummer
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - Cláudia Lobato da Silva
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
| | - Joaquim M S Cabral
- Department of Bioengineering and iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
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18
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Pereira CF, Olean-Oliveira A, David-Parra DN, Teixeira MF. A chemiresistor sensor based on a cobalt(salen) metallopolymer for dissolved molecular oxygen. Talanta 2018; 190:119-125. [DOI: 10.1016/j.talanta.2018.07.080] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/22/2018] [Accepted: 07/24/2018] [Indexed: 11/17/2022]
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19
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Jiang Z, Chen J, Du J, Liu T, Li X, Yu H, Zhang Q, Hu Y, Liu F, Yu X, Zhou Z. Ratiometric optical sensor for high-resolution imaging of pH with low cross-talk. APPLIED OPTICS 2018; 57:9922-9928. [PMID: 30645247 DOI: 10.1364/ao.57.009922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/23/2018] [Indexed: 06/09/2023]
Abstract
We synthesize lipophilic, highly efficient, and pH-insensitive oleic acid-modified quantum dots (QDs) with maximum emission at a wavelength of 628 nm. The pH sensing film is fabricated by encapsulating 5-hexadecanoylamino-fluorescein and QDs as the reference in D4-hydromed and plasticized polystyrene. Using a light-emitting diode with a central wavelength of 410 nm as an excitation source, it is shown that the emission wavelengths of the pH sensitive indicator and reference dye have no spectral overlap and match respectively the channels of a 3CCD (RGB) camera with low cross-talk. A series of validation experiments shows that this ratiometric pH optode has good properties of high sensitivity, long-term stability, and photostability. It had a fast response time of <20 s when going from pH 6.3 to pH 8.0. The pH images suggest that the proposed ratiometric pH-sensing approach has great advantage and promise for field applications.
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20
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Krieg T, Phan LMP, Wood JA, Sydow A, Vassilev I, Krömer JO, Mangold KM, Holtmann D. Characterization of a membrane-separated and a membrane-less electrobioreactor for bioelectrochemical syntheses. Biotechnol Bioeng 2018; 115:1705-1716. [DOI: 10.1002/bit.26600] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 02/22/2018] [Accepted: 03/19/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Thomas Krieg
- Industrial Biotechnology; DECHEMA Forschungsinstitut; Frankfurt am Main Hessen Germany
| | - Linh M. P. Phan
- Industrial Biotechnology; DECHEMA Forschungsinstitut; Frankfurt am Main Hessen Germany
| | - Jeffery A. Wood
- Soft Matter, Fluidics and Interfaces, Faculty of Science and Technology; University of Twente; Enschede The Netherlands
| | - Anne Sydow
- Industrial Biotechnology; DECHEMA Forschungsinstitut; Frankfurt am Main Hessen Germany
| | - Igor Vassilev
- Centre for Microbial Electrochemical Systems (CEMES); The University of Queensland; Brisbane Australia
- Advanced Water Management Centre (AWMC); The University of Queensland; Brisbane Australia
| | - Jens O. Krömer
- Centre for Microbial Electrochemical Systems (CEMES); The University of Queensland; Brisbane Australia
- Advanced Water Management Centre (AWMC); The University of Queensland; Brisbane Australia
- Department for Solar Materials; Helmholtz Centre for Environmental Research (UFZ); Leipzig Germany
| | | | - Dirk Holtmann
- Industrial Biotechnology; DECHEMA Forschungsinstitut; Frankfurt am Main Hessen Germany
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21
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Staying alive! Sensors used for monitoring cell health in bioreactors. Talanta 2018; 176:130-139. [DOI: 10.1016/j.talanta.2017.07.088] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/25/2017] [Accepted: 07/28/2017] [Indexed: 01/10/2023]
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22
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Enhancing cell and gene therapy manufacture through the application of advanced fluorescent optical sensors (Review). Biointerphases 2017; 13:01A301. [PMID: 29246035 DOI: 10.1116/1.5013335] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cell and gene therapies (CGTs) are examples of future therapeutics that can be used to cure or alleviate the symptoms of disease, by repairing damaged tissue or reprogramming defective genetic information. However, despite the recent advancements in clinical trial outcomes, the path to wide-scale adoption of CGTs remains challenging, such that the emergence of a "blockbuster" therapy has so far proved elusive. Manufacturing solutions for these therapies require the application of scalable and replicable cell manufacturing techniques, which differ markedly from the existing pharmaceutical incumbent. Attempts to adopt this pharmaceutical model for CGT manufacture have largely proved unsuccessful. The most significant challenges facing CGT manufacturing are process analytical testing and quality control. These procedures would greatly benefit from improved sensory technologies that allow direct measurement of critical quality attributes, such as pH, oxygen, lactate and glucose. In turn, this would make manufacturing more robust, replicable and standardized. In this review, the present-day state and prospects of CGT manufacturing are discussed. In particular, the authors highlight the role of fluorescent optical sensors, focusing on their strengths and weaknesses, for CGT manufacture. The review concludes by discussing how the integration of CGT manufacture and fluorescent optical sensors could augment future bioprocessing approaches.
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Kattipparambil Rajan D, Patrikoski M, Verho J, Sivula J, Ihalainen H, Miettinen S, Lekkala J. Optical non-contact pH measurement in cell culture with sterilizable, modular parts. Talanta 2016; 161:755-761. [DOI: 10.1016/j.talanta.2016.09.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/02/2016] [Accepted: 09/05/2016] [Indexed: 01/22/2023]
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24
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Shao J, Xiang J, Axner O, Ying C. Wavelength-modulated tunable diode-laser absorption spectrometry for real-time monitoring of microbial growth. APPLIED OPTICS 2016; 55:2339-45. [PMID: 27140571 DOI: 10.1364/ao.55.002339] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
It is important to monitor and assess the growth of micro-organisms under various conditions. Yet, thus far there has been no technique to do this with the required speed and accuracy. This work demonstrates swift and accurate assessment of the concentration of carbon dioxide that is produced by use of a wavelength-modulated tunable diode-laser based absorption spectroscopy (WM-TDLAS). It is shown by experiments on two types of bacteria, Staphylococcus aureus and Candida albicans, that the technique can produce high signal-to-noise-ratio data from bacteria grown in confined spaces and exposed to limited amounts of nutrients that can be used for extraction of growth parameters by fitting of the Gompertz model. By applying the technique to S. aureus bacteria at various temperatures (in the 25°C to 42°C range), it is specifically shown that both the maximum growth rate and the so-called lag time have a strong temperature dependence (under the specific conditions with a maximum of the former at 37°C) that matches conventional models well for bacterial growth. Hence, it is demonstrated that WM-TDLAS monitoring CO2 is a user-friendly, non-intrusive, and label-free technique that swiftly, and with high signal-to-noise-ratio, can be used for rapid (on the Hz scale) and accurate assessment of bacterial growth.
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25
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Demuth C, Varonier J, Jossen V, Eibl R, Eibl D. Novel probes for pH and dissolved oxygen measurements in cultivations from millilitre to benchtop scale. Appl Microbiol Biotechnol 2016; 100:3853-63. [DOI: 10.1007/s00253-016-7412-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/18/2016] [Accepted: 02/22/2016] [Indexed: 12/31/2022]
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Improved Stability of a Model IgG3 by DoE-Based Evaluation of Buffer Formulations. BIOMED RESEARCH INTERNATIONAL 2016; 2016:2074149. [PMID: 27042659 PMCID: PMC4794585 DOI: 10.1155/2016/2074149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/20/2015] [Accepted: 11/29/2015] [Indexed: 02/03/2023]
Abstract
Formulating appropriate storage conditions for biopharmaceutical proteins is essential for ensuring their stability and thereby their purity, potency, and safety over their shelf-life. Using a model murine IgG3 produced in a bioreactor system, multiple formulation compositions were systematically explored in a DoE design to optimize the stability of a challenging antibody formulation worst case. The stability of the antibody in each buffer formulation was assessed by UV/VIS absorbance at 280 nm and 410 nm and size exclusion high performance liquid chromatography (SEC) to determine overall solubility, opalescence, and aggregate formation, respectively. Upon preliminary testing, acetate was eliminated as a potential storage buffer due to significant visible precipitate formation. An additional 24 full factorial DoE was performed that combined the stabilizing effect of arginine with the buffering capacity of histidine. From this final DoE, an optimized formulation of 200 mM arginine, 50 mM histidine, and 100 mM NaCl at a pH of 6.5 was identified to substantially improve stability under long-term storage conditions and after multiple freeze/thaw cycles. Thus, our data highlights the power of DoE based formulation screening approaches even for challenging monoclonal antibody molecules.
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27
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Berry BN, Dobrowsky TM, Timson RC, Kshirsagar R, Ryll T, Wiltberger K. Quick generation of Raman spectroscopy based in-process glucose control to influence biopharmaceutical protein product quality during mammalian cell culture. Biotechnol Prog 2015; 32:224-34. [DOI: 10.1002/btpr.2205] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 11/10/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Brandon N. Berry
- Biogen Inc; 250 Binney Street 02142 Cambridge Massachusetts United States
| | | | - Rebecca C. Timson
- Biogen Inc; 250 Binney Street 02142 Cambridge Massachusetts United States
| | - Rashmi Kshirsagar
- Biogen Inc; 250 Binney Street 02142 Cambridge Massachusetts United States
| | - Thomas Ryll
- Biogen Inc; 250 Binney Street 02142 Cambridge Massachusetts United States
| | - Kelly Wiltberger
- Biogen Inc; 5000 Davis Drive 27709 Research Triangle Park North Carolina United States
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28
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Reinwald Y, Leonard KHL, Henstock JR, Whiteley JP, Osborne JM, Waters SL, Levesque P, El Haj AJ. Evaluation of the growth environment of a hydrostatic force bioreactor for preconditioning of tissue-engineered constructs. Tissue Eng Part C Methods 2015; 21:1-14. [PMID: 24967717 DOI: 10.1089/ten.tec.2013.0476] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bioreactors have been widely acknowledged as valuable tools to provide a growth environment for engineering tissues and to investigate the effect of physical forces on cells and cell-scaffold constructs. However, evaluation of the bioreactor environment during culture is critical to defining outcomes. In this study, the performance of a hydrostatic force bioreactor was examined by experimental measurements of changes in dissolved oxygen (O2), carbon dioxide (CO2), and pH after mechanical stimulation and the determination of physical forces (pressure and stress) in the bioreactor through mathematical modeling and numerical simulation. To determine the effect of hydrostatic pressure on bone formation, chick femur skeletal cell-seeded hydrogels were subjected to cyclic hydrostatic pressure at 0-270 kPa and 1 Hz for 1 h daily (5 days per week) over a period of 14 days. At the start of mechanical stimulation, dissolved O2 and CO2 in the medium increased and the pH of the medium decreased, but remained within human physiological ranges. Changes in physiological parameters (O2, CO2, and pH) were reversible when medium samples were placed in a standard cell culture incubator. In addition, computational modeling showed that the distribution and magnitude of physical forces depends on the shape and position of the cell-hydrogel constructs in the tissue culture format. Finally, hydrostatic pressure was seen to enhance mineralization of chick femur skeletal cell-seeded hydrogels.
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Affiliation(s)
- Yvonne Reinwald
- 1 Institute of Science and Technology in Medicine, University of Keele , Stoke-on-Trent, United Kingdom
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29
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Peretz-Soroka H, Pevzner A, Davidi G, Naddaka V, Kwiat M, Huppert D, Patolsky F. Manipulating and Monitoring On-Surface Biological Reactions by Light-Triggered Local pH Alterations. NANO LETTERS 2015; 15:4758-4768. [PMID: 26086686 DOI: 10.1021/acs.nanolett.5b01578] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Significant research efforts have been dedicated to the integration of biological species with electronic elements to yield smart bioelectronic devices. The integration of DNA, proteins, and whole living cells and tissues with electronic devices has been developed into numerous intriguing applications. In particular, the quantitative detection of biological species and monitoring of biological processes are both critical to numerous areas of medical and life sciences. Nevertheless, most current approaches merely focus on the "monitoring" of chemical processes taking place on the sensing surfaces, and little efforts have been invested in the conception of sensitive devices that can simultaneously "control" and "monitor" chemical and biological reactions by the application of on-surface reversible stimuli. Here, we demonstrate the light-controlled fine modulation of surface pH by the use of photoactive molecularly modified nanomaterials. Through the use of nanowire-based FET devices, we showed the capability of modulating the on-surface pH, by intensity-controlled light stimulus. This allowed us simultaneously and locally to control and monitor pH-sensitive biological reactions on the nanodevices surfaces, such as the local activation and inhibition of proteolytic enzymatic processes, as well as dissociation of antigen-antibody binding interactions. The demonstrated capability of locally modulating the on-surface effective pH, by a light stimuli, may be further applied in the local control of on-surface DNA hybridization/dehybridization processes, activation or inhibition of living cells processes, local switching of cellular function, local photoactivation of neuronal networks with single cell resolution and so forth.
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Affiliation(s)
- Hagit Peretz-Soroka
- †School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Alexander Pevzner
- †School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guy Davidi
- †School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Vladimir Naddaka
- †School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Moria Kwiat
- †School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dan Huppert
- †School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Fernando Patolsky
- †School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
- ‡The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv 69978, Israel
- §Department of Materials Science and Engineering, the Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
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30
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Sardesai N, Rao G, Kostov Y. Versatile common instrumentation for optical detection of pH and dissolved oxygen. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:074302. [PMID: 26233397 DOI: 10.1063/1.4926542] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The recent trend toward use of disposable and miniature bioreactors requires the use of appropriate sensors. pH and dissolved oxygen (DO) are often measured using optical chemical sensors due to their small form factor and convenience in use. These sensors are often interrogated using a specialized opto-electronic transducer that is designed around the optical sensor. In this contribution, we are presenting a new class of opto-electronic transducers that are usable with several different chemical sensors without the need to switch the optics or hardware when changing the type of the chemical sensor. This allows flexibility closer to the lab-grade devices while the size is closer to a dedicated sensor. This versatile instrumentation is capable of seamlessly switching between the pH and DO measurement modes and is capable of auto recognition of the sensor type. The principle of ratiometric fluorescence is used for pH measurements, and that of fluorescence lifetime for DO measurements. An approach to obtain identical calibrations between several devices is also presented. The described hardware constitutes common instrumentation for measuring either pH or DO and has been tested in actual bioprocesses. It has been found adequate for continuous bioprocess monitoring.
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Affiliation(s)
- Neha Sardesai
- Department of Computer Science and Electrical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA
| | - Govind Rao
- Center for Advanced Sensor Technology and Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA
| | - Yordan Kostov
- Department of Computer Science and Electrical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA
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31
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Biechele P, Busse C, Solle D, Scheper T, Reardon K. Sensor systems for bioprocess monitoring. Eng Life Sci 2015. [DOI: 10.1002/elsc.201500014] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Philipp Biechele
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Christoph Busse
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Dörte Solle
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Thomas Scheper
- Institute of Technical Chemistry; Leibniz University; Hannover Germany
| | - Kenneth Reardon
- Department of Chemical and Biological Engineering; Colorado State University; Fort Collins CO USA
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32
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Silva AC, Simão D, Küppers C, Lucas T, Sousa MFQ, Cruz P, Carrondo MJT, Kochanek S, Alves PM. Human amniocyte-derived cells are a promising cell host for adenoviral vector production under serum-free conditions. Biotechnol J 2015; 10:760-71. [DOI: 10.1002/biot.201400765] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 04/02/2015] [Accepted: 04/13/2015] [Indexed: 11/09/2022]
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33
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Online flow cytometry for monitoring apoptosis in mammalian cell cultures as an application for process analytical technology. Cytotechnology 2014; 68:399-408. [PMID: 25352493 DOI: 10.1007/s10616-014-9791-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/24/2014] [Indexed: 12/20/2022] Open
Abstract
Apoptosis is the main driver of cell death in bioreactor suspension cell cultures during the production of biopharmaceuticals from animal cell lines. It is known that apoptosis also has an effect on the quality and quantity of the expressed recombinant protein. This has raised the importance of studying apoptosis for implementing culture optimization strategies. The work here describes a novel approach to obtain near real time data on proportion of viable, early apoptotic, late apoptotic and necrotic cell populations in a suspension CHO culture using automated sample preparation in conjunction with flow cytometry. The resultant online flow cytometry data can track the progression of apoptotic events in culture, aligning with analogous manual methodologies and giving similar results. The obtained near-real time apoptosis data are a significant improvement in monitoring capabilities and can lead to improved control strategies and research data on complex biological systems in bioreactor cultures in both academic and industrial settings focused on process analytical technology applications.
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34
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35
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Gupta PA, Ge X, Kostov Y, Rao G. A completely noninvasive method of dissolved oxygen monitoring in disposable small-scale cell culture vessels based on diffusion through permeable vessel walls. Biotechnol Prog 2013; 30:172-7. [DOI: 10.1002/btpr.1838] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 10/25/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Priyanka A. Gupta
- Center for Advanced Sensor Technology; Dept. of Chemical; Biochemical and Environmental Engineering; University of Maryland, Baltimore County; Baltimore MD 21250
| | - Xudong Ge
- Center for Advanced Sensor Technology; Dept. of Chemical; Biochemical and Environmental Engineering; University of Maryland, Baltimore County; Baltimore MD 21250
| | - Yordan Kostov
- Center for Advanced Sensor Technology; Dept. of Chemical; Biochemical and Environmental Engineering; University of Maryland, Baltimore County; Baltimore MD 21250
| | - Govind Rao
- Center for Advanced Sensor Technology; Dept. of Chemical; Biochemical and Environmental Engineering; University of Maryland, Baltimore County; Baltimore MD 21250
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36
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Peretz-Soroka H, Pevzner A, Davidi G, Naddaka V, Tirosh R, Flaxer E, Patolsky F. Optically-gated self-calibrating nanosensors: monitoring pH and metabolic activity of living cells. NANO LETTERS 2013; 13:3157-3168. [PMID: 23772673 DOI: 10.1021/nl401169k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Quantitative detection of biological and chemical species is critical to numerous areas of medical and life sciences. In this context, information regarding pH is of central importance in multiple areas, from chemical analysis, through biomedical basic studies and medicine, to industry. Therefore, a continuous interest exists in developing new, rapid, miniature, biocompatible and highly sensitive pH sensors for minute fluid volumes. Here, we present a new paradigm in the development of optoelectrical sensing nanodevices with built-in self-calibrating capabilities. The proposed electrical devices, modified with a photoactive switchable molecular recognition layer, can be optically switched between two chemically different states, each having different chemical binding constants and as a consequence affecting the device surface potential at different extents, thus allowing the ratiometric internal calibration of the sensing event. At each point in time, the ratio of the electrical signals measured in the ground and excited states, respectively, allows for the absolute concentration measurement of the molecular species under interest, without the need for electrical calibration of individual devices. Furthermore, we applied these devices for the real-time monitoring of cellular metabolic activity, extra- and intracellularly, as a potential future tool for the performance of basic cell biology studies and high-throughput personalized medicine-oriented research, involving single cells and tissues. This new concept can be readily expanded to the sensing of additional chemical and biological species by the use of additional photoactive switchable receptors. Moreover, this newly demonstrated coupling between surface-confined photoactive molecular species and nanosensing devices could be utilized in the near future in the development of devices of higher complexity for both the simultaneous control and monitoring of chemical and biological processes with nanoscale resolution control.
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Affiliation(s)
- Hagit Peretz-Soroka
- School of Chemistry, the Raymond and Beverly Sackler Faculty of Exact Sciences and ‡The Center for Nanoscience and Nanotechnology, Tel-Aviv University , Tel Aviv 69978, Israel
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Read EK, Bradley SA, Smitka TA, Agarabi CD, Lute SC, Brorson KA. Fermentanomics informed amino acid supplementation of an antibody producing mammalian cell culture. Biotechnol Prog 2013; 29:745-53. [PMID: 23606649 DOI: 10.1002/btpr.1728] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 03/07/2013] [Indexed: 01/23/2023]
Abstract
Fermentanomics, or a global understanding of a culture state on the molecular level empowered by advanced techniques like NMR, was employed to show that a model hybridoma culture supplied with glutamine and glucose depletes aspartate, cysteine, methionine, tryptophan, and tyrosine during antibody production. Supplementation with these amino acids prevents depletion and improves culture performance. Furthermore, no significant changes were observed in the distribution of glycans attached to the IgG3 in cultures supplemented with specific amino acids, arguing that this strategy can be implemented without fear of impact on important product quality attributes. In summary, a targeted strategy of quantifying media components and designing a supplementation strategy can improve bioprocess cell cultures when enpowered by fermentanomics tools.
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Affiliation(s)
- Erik K Read
- Div. of Monoclonal Antibodies, CDER, FDA, Silver Spring, MD, USA
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Kirk TV, Szita N. Oxygen transfer characteristics of miniaturized bioreactor systems. Biotechnol Bioeng 2013; 110:1005-19. [PMID: 23280578 PMCID: PMC3790518 DOI: 10.1002/bit.24824] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 11/08/2012] [Accepted: 12/06/2012] [Indexed: 12/02/2022]
Abstract
Since their introduction in 2001 miniaturized bioreactor systems have made great advances in function and performance. In this article the dissolved oxygen (DO) transfer performance of submilliliter microbioreactors, and 1–10 mL minibioreactors was examined. Microbioreactors have reached kLa values of 460 h-1, and are offering instrumentation and some functionality comparable to production systems, but at high throughput screening volumes. Minibioreactors, aside from one 1,440 h-1kLa system, have not offered as high rates of DO transfer, but have demonstrated superior integration with automated fluid handling systems. Microbioreactors have been typically limited to studies with E. coli, while minibioreactors have offered greater versatility in this regard. Further, mathematical relationships confirming the applicability of kLa measurements across all scales have been derived, and alternatives to fluorescence lifetime DO sensors have been evaluated. Finally, the influence on reactor performance of oxygen uptake rate (OUR), and the possibility of its real-time measurement have been explored. Biotechnol. Bioeng. 2013; 110: 1005–1019. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Timothy V Kirk
- Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE United Kingdom
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Cook MT, Saratoon T, Tzortzis G, Edwards A, Charalampopoulos D, Khutoryanskiy VV. CLSM method for the dynamic observation of pH change within polymer matrices for oral delivery. Biomacromolecules 2013; 14:387-93. [PMID: 23301617 DOI: 10.1021/bm301569r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
If acid-sensitive drugs or cells are administered orally, there is often a reduction in efficacy associated with gastric passage. Formulation into a polymer matrix is a potential method to improve their stability. The visualization of pH within these materials may help better understand the action of these polymer systems and allow comparison of different formulations. We herein describe the development of a novel confocal laser-scanning microscopy (CLSM) method for visualizing pH changes within polymer matrices and demonstrate its applicability to an enteric formulation based on chitosan-coated alginate gels. The system in question is first shown to protect an acid-sensitive bacterial strain to low pH, before being studied by our technique. Prior to this study, it has been claimed that protection by these materials is a result of buffering, but this has not been demonstrated. The visualization of pH within these matrices during exposure to a pH 2.0 simulated gastric solution showed an encroachment of acid from the periphery of the capsule, and a persistence of pHs above 2.0 within the matrix. This implies that the protective effect of the alginate-chitosan matrices is most likely due to a combination of buffering of acid as it enters the polymer matrix and the slowing of acid penetration.
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Affiliation(s)
- Michael T Cook
- Department of Food and Nutritional Sciences and ‡Reading School of Pharmacy, University of Reading, Reading, United Kingdom
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Hillig F, Pilarek M, Junne S, Neubauer P. Cultivation of Marine Microorganisms in Single-Use Systems. DISPOSABLE BIOREACTORS II 2013; 138:179-206. [DOI: 10.1007/10_2013_219] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Vishwanathan AS, Rao G, Siva Sankara Sai S. A novel minimally invasive method for monitoring oxygen in microbial fuel cells. Biotechnol Lett 2012; 35:553-8. [DOI: 10.1007/s10529-012-1109-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 11/19/2012] [Indexed: 10/27/2022]
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Abstract
Continuous monitoring of oxygen concentration is of great importance in many different areas of research which range from medical applications to food packaging. In the last three decades, significant progress has been made in the field of optical sensing technology and this review will highlight the one inherent to the development of oxygen indicators. The first section outlines the bioanalytical fields in which optical oxygen sensors have been applied. The second section gives the reader a comprehensive summary of the existing oxygen indicators with a critical highlight on their photophysical and sensing properties. Altogether, this review is meant to give the potential user a guide to select the most suitable oxygen indicator for the particular application of interest.
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Pierzchalski A, Hebeisen M, Mittag A, Bocsi J, Di Berardino M, Tarnok A. Label-free hybridoma cell culture quality control by a chip-based impedance flow cytometer. LAB ON A CHIP 2012; 12:4533-4543. [PMID: 22907524 DOI: 10.1039/c2lc40408g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Impedance flow cytometry (IFC) was evaluated as a possible alternative to fluorescence-based methods for on-line quality monitoring of hybridoma cells. Hybridoma cells were cultured at different cell densities and viability was estimated by means of IFC and fluorescence-based flow cytometry (FCM). Cell death was determined by measuring the impedance phase value at high frequency in low conductivity buffer. IFC data correlate well with reference FCM measurements using AnnexinV and 7-AAD staining. Hybridoma cells growing at different densities in cell culture revealed a density-dependent subpopulation pattern. Living cells of high density cultures show reduced impedance amplitudes, indicating particular cellular changes. Dead cell subpopulations become evident in cultures with increasing cell densities. In addition, a novel intermediate subpopulation, which most probably represents apoptotic cells, was identified. These results emphasize the extraordinary sensitivity of high frequency impedance measurements and their suitability for hybridoma cell culture quality control.
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Kondragunta B, Joshi BH, Han J, Brorson KA, Puri RK, Moreira AR, Rao G. Bioreactor environment-sensitive sentinel genes as novel metrics for cell culture scale-down comparability. Biotechnol Prog 2012; 28:1138-51. [DOI: 10.1002/btpr.1606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 07/11/2012] [Indexed: 12/18/2022]
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Quality by design: impact of formulation variables and their interactions on quality attributes of a lyophilized monoclonal antibody. Int J Pharm 2012; 438:167-75. [PMID: 22944306 DOI: 10.1016/j.ijpharm.2012.08.033] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 07/25/2012] [Accepted: 08/18/2012] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to use QbD approaches to evaluate the effect of several variables and their interactions on quality of a challenging model murine IgG3κ monoclonal antibody (mAb), and then to obtain an optimized formulation with predefined quality target product profile. This antibody was chosen because it has a propensity to precipitate and thus represents a challenge condition for formulation development. Preliminary experiments were conducted to rule out incompatible buffer systems for the mAb product quality. A fractional factorial experimental design was then applied to screen the effects of buffer type, pH and excipients such as sucrose, sodium chloride (NaCl), lactic acid and Polysorbate 20 on glass transition temperature ( [Formula: see text] ), monoclonal antibody concentration (A(280)), presence of aggregation, unfolding transition temperature (T(m)) of the lyophilized product, and particle size of the reconstituted product. A Box-Behnken experimental design was subsequently applied to study the main, interaction, and quadratic effects of these variables on the responses. Pareto ranking analyses showed that the three most important factors affecting the selected responses for this particular antibody were pH, NaCl, and Polysorbate 20. The presence of curvature in the variables' effects on responses indicated interactions. Based on the constraints set on the responses, a design space was identified for this mAb and confirmed with experiments at three different levels of the variables within the design space. The model indicated a combination of high pH (8) and NaCl (50mM) levels, and a low Polysorbate 20 (0.008 mM) level at which an optimal formulation of the mAb could be achieved. Moisture contents and other analytical procedures such as size exclusion chromatography, protein A analysis and SDS-PAGE of the pre-lyophilized and final reconstituted lyophilized products indicated an intact protein structure with minimal aggregation after formulation and lyophilization. In conclusion, experimental design approach was effective in identifying optimal concentrations of excipients and pH for this challenging monoclonal antibody formulation.
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Ge X, Kostov Y, Tolosa L, Rao G. Study on low-cost calibration-free pH sensing with disposable optical sensors. Anal Chim Acta 2012; 734:79-87. [PMID: 22704475 DOI: 10.1016/j.aca.2012.05.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 05/14/2012] [Accepted: 05/16/2012] [Indexed: 11/19/2022]
Abstract
As labor costs become more expensive, less labor-intensive disposable devices have become more ubiquitous. Similarly, the disposable optical pH sensor developed in our lab could provide a convenient yet cost-effective way for pH sensing in processes that require stringent pH control. This optical pH sensor is prepared in uniform individual lots of 100-200 sensors per lot. Calibration is accomplished on a few randomly selected sensors out of each lot. We show that all others in the same lot can then be used directly without requiring individual calibration. In this paper, a calibration model is derived to include all the factors that affect the signal of the disposable sensor. Experimental results show that the derived calibration model fits the experimental data. The readings of 28 randomly selected disposable sensors with 4 sensors from each of the 7 lots show an error less than 0.1 pH units in the useful sensing range of the sensor. The calibration model indicates that if further improvement on precision is desired, more uniform porous material and more advanced coating techniques will be required. When it comes to the effects of the varying coasters, house-made low-cost fluorometers, the variability in the brightness ratio of the blue-to-violet LEDs is the primary reason for the lack of precision. Other factors like LED light intensity distribution, optical properties of the filters and electronics also contribute to the coaster-to-coaster difference, but to a lesser extent. Two different methods for correcting the instrument variations were introduced. After correction, the collective reading errors for all the tested instruments were reduced to less than 0.2 pH units within the sensor's useful sensing range. Based on this result, our lab is currently implementing further improvements in modifying the coasters to equalize the ratios of blue-to-violet LED brightness.
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Affiliation(s)
- Xudong Ge
- Center for Advanced Sensor Technology, Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
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Kuystermans D, Mohd A, Al-Rubeai M. Automated flow cytometry for monitoring CHO cell cultures. Methods 2012; 56:358-65. [PMID: 22445707 DOI: 10.1016/j.ymeth.2012.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 02/08/2012] [Accepted: 03/02/2012] [Indexed: 11/26/2022] Open
Abstract
Flow cytometry has been used to accurately monitor cell events that indicate the spatio-temporal state of a bioreactor culture. The introduction of process analytical technology (PAT) has led to process improvements using real-time or semi real-time monitoring systems. Integration of flow cytometry into an automated scheme for improved process monitoring can benefit PAT in bioreactor-based biopharmaceutical productions by establishing optimum process conditions and better quality protocols. Herein, we provide detailed protocols for establishing an automated flow cytometry system that can be used to investigate and monitor cell growth, viability, cell size, and cell cycle data. A method is described for the use of such a system primarily focused on CHO cell culture, although it is foreseen the information gathered from automated flow cytometry can be applied to a variety of cell lines to address both PAT requirements and gain further understanding of complex biological systems.
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Affiliation(s)
- Darrin Kuystermans
- School of Chemical and Bioprocess Engineering, Centre for Synthesis and Chemical Biology-CSCB, University College Dublin, Belfield, Dublin 4, Ireland.
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Ge X, Rao G. Real-time monitoring of shake flask fermentation and off gas using triple disposable noninvasive optical sensors. Biotechnol Prog 2012; 28:872-7. [DOI: 10.1002/btpr.1528] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 01/31/2012] [Indexed: 11/07/2022]
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Hakonen A, Strömberg N. Diffusion consistent calibrations for improved chemical imaging using nanoparticle enhanced optical sensors. Analyst 2012; 137:315-21. [DOI: 10.1039/c1an15528h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Strömberg N, Hakonen A. Plasmophore sensitized imaging of ammonia release from biological tissues using optodes. Anal Chim Acta 2011; 704:139-45. [PMID: 21907031 DOI: 10.1016/j.aca.2011.08.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 08/02/2011] [Accepted: 08/08/2011] [Indexed: 11/26/2022]
Abstract
A plasmophore sensitized optode was developed for imaging ammonia (NH(3)) concentrations in muscle tissues. The developed ammonia sensor and an equivalent non plasmophore version of the sensor were tested side by side to compare their limit of detection, dynamic range, reversibility and overall imaging quality. Bio-degradation patterns of ammonia release from lean porcine skeletal muscle were studied over a period of 11 days. We demonstrate that ammonia concentrations ranging from 10nM can be quantified reversibly with an optical resolution of 127 μm in a sample area of 25 mm × 35 mm. The plasmophore ammonia optode showed improved reversibility, less false pixels and a 2 nM ammonia detection limit compared to 200 nM for the non-plasmophore sensor. Main principles of the sensing mechanism include ammonia transfer over a gas permeable film, ammonia protonation, nonactin facilitated merocyanine-ammonium coextraction and plasmophore enhancement. The vast signal improvement is suggested to rely on solvatochroism, nanoparticle scattering and plasmonic interactions that are utilized constructively in a fluorescence ratio. In addition to fundamental medicinal and biological research applications in tissue physiology, reversible ammonia quantification will be possible for a majority of demanding imaging and non imaging applications such as monitoring of low ammonia background concentrations in air and non-invasive medicinal diagnosis through medical breath or saliva analysis. The nanoparticle doped sensor constitutes a highly competitive technique for ammonia sensing in complex matrixes and the general sensing scheme offers new possibilities for the development of artificial optical noses and tongues.
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