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Lee JH, Park HJ, Kim YA, Lee DH, Noh JK, Jung JG, Yang MS, Lee JE, Lee SH, Yoon HH, Lee SK, Lee S. Selecting serum-free hepatocyte cryopreservation stage and storage temperature for the application of an "off-the-shelf" bioartificial liver system. Sci Rep 2024; 14:12168. [PMID: 38806510 PMCID: PMC11133438 DOI: 10.1038/s41598-024-60711-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 04/26/2024] [Indexed: 05/30/2024] Open
Abstract
The bioartificial liver (BAL) system can potentially rescue acute liver failure (ALF) patients by providing partial liver function until a suitable donor liver can be found or the native liver has self-regenerated. In this study, we established a suitable cryopreservation process for the development of an off-the-shelf BAL system. The viability of hepatocyte spheroids cryopreserved in liquid nitrogen was comparable to that of fresh primary hepatocyte spheroids. When hepatocyte spheroids were subjected to cryopreservation in a deep freezer, no statistically significant differences were observed in ammonia removal rate or urea secretion rate based on the cryopreservation period. However, the functional activity of the liver post-cryopreservation in a deep freezer was significantly lower than that observed following liquid nitrogen cryopreservation. Moreover, cryopreserving spheroid hydrogel beads in a deep freezer resulted in a significant decrease (approximately 30%) in both ammonia removal and urea secretion rates compared to the group cryopreserved in liquid nitrogen. The viabilities of spheroid hydrogel beads filled into the bioreactor of a BAL system were similar across all four groups. However, upon operating the BAL system for 24 h, the liver function activity was significantly higher in the group comprising hydrogel beads generated after thawing hepatocyte spheroids cryopreserved in liquid nitrogen. Consequently, the manufacturing of beads after the cryopreservation of hepatocyte spheroids is deemed the most suitable method, considering efficiency, economic feasibility, and liver function activity, for producing a BAL system.
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Affiliation(s)
- Ji-Hyun Lee
- Stem Cell and Regenerative Medicine Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Hey-Jung Park
- Stem Cell and Regenerative Medicine Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Young-A Kim
- Stem Cell and Regenerative Medicine Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Doo-Hoon Lee
- Research Institute, HLB Cell, Co. Ltd., Hwaseong, Republic of Korea
| | - Jeong-Kwon Noh
- Research Institute, HLB Cell, Co. Ltd., Hwaseong, Republic of Korea
| | - Jong-Gab Jung
- Research Institute, HLB Cell, Co. Ltd., Hwaseong, Republic of Korea
| | - Mal Sook Yang
- Research Institute, HLB Cell, Co. Ltd., Hwaseong, Republic of Korea
| | - Jong Eun Lee
- Research Institute, HLB Cell, Co. Ltd., Hwaseong, Republic of Korea
| | - Se Hoon Lee
- Research Institute, HLB Cell, Co. Ltd., Hwaseong, Republic of Korea
| | - Hee-Hoon Yoon
- Research Institute, HLB Cell, Co. Ltd., Hwaseong, Republic of Korea
| | - Suk-Koo Lee
- Department of Surgery, Myongji Hospital, Goyang, Republic of Korea.
| | - Sanghoon Lee
- Department of Surgery, School of Medicine, Samsung Medical Center, Sungkyunkwan University, 50 Irwon-Dong, Gangnam-Gu, Seoul, 06354, Republic of Korea.
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Gonzalez-Martinez N, Gibson MI. Post-thaw application of ROCK-inhibitors increases cryopreserved T-cell yield. RSC Med Chem 2023; 14:2058-2067. [PMID: 37859712 PMCID: PMC10583820 DOI: 10.1039/d3md00378g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 08/18/2023] [Indexed: 10/21/2023] Open
Abstract
Emerging cell-based therapies such as CAR-T (Chimeric Antigen Receptor T) cells require cryopreservation to store and deliver intact and viable cells. Conventional cryopreservation formulations use DMSO to mitigate cold-induced damage, but do not address all the biochemical damage mechanisms induced by cold stress, such as programmed cell death (apoptosis). Rho-associated protein kinases (ROCK) are a key component of apoptosis, and their activation contributes to apoptotic blebbing. Here we demonstrate that the ROCK inhibitor fasudil hydrochloride, when supplemented into the thawing medium of T-cells increases the overall yield of healthy cells. Cell yield was highest using 5 or 10% DMSO cryopreservation solutions, with lower DMSO concentrations (2.5%) leading to significant physical damage to the cells. After optimisation, the post-thaw yield of T-cells increased by approximately 20% using this inhibitor, a significant increase in the context of a therapy. Flow cytometry analysis did not show a significant reduction in the relative percentage of cell populations undergoing apoptosis, but there was a small reduction in the 8 hours following thawing. Fasudil also led to a reduction in reactive oxygen species. Addition of fasudil into the cryopreservation solution, followed by dilution (rather than washing) upon thaw also gave a 20% increase in cell yield, demonstrating how this could be deployed in a cell-therapy context, without needing to change clinical thawing routines. Overall, this shows that modulation of post-thaw biochemical pathways which lead to apoptosis (or other degradative pathways) can be effectively targeted as a strategy to increase T-cell yield and function post-thaw.
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Affiliation(s)
| | - Matthew I Gibson
- Department of Chemistry, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick Gibbet Hill Road Coventry CV4 7AL UK
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Kozlova VA, Pokrovskaya MS, Meshkov AN, Drapkina OM. Actual approaches to the transportation of biological samples at low temperatures. Klin Lab Diagn 2020; 65:619-625. [PMID: 33245651 DOI: 10.18821/0869-2084-2020-65-10-619-625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Taking into account the impact of shipment method of biosamples is necessary for obtaining high-quality biological samples in biobanking and laboratory research. The impact of liquid nitrogen, dry ice and cold accumulators on the quality of biological markers was considered, as well as recommendations to reduce the impact of these methods of shipment. The liquid nitrogen provides the best preservation of samples, however, dry ice is used much more often during their transportation. When transporting certain types of cells using dry ice, there is the way to use CryoStor CS1 and Cell Banker 1 cryoprotectors. The dry ice has a significant effect on both the pH of liquid biological samples and the coagulological parameters of plasma samples. The penetration of CO2 into the sample leads to changes in the parameters of PTT and APPT, as well as to decrease the protein C and fibrinogen level under certain conditions. Serum and plasma samples exposed to dry ice for more than 16 hours should be thawed open at room temperature, or instead of it should be kept at -80 °C for 24 hours to avoid changes in coagulation parameters, The use of cold accumulators is unacceptable for long-term shipment of serum and plasma containing unstable biomarkers because of insufficiently low temperature (increase over time to -25 °C and above). Besides, metal pellets can be used as cold storage batteries at low temperatures (up to -80 ° C), but they are not as effective as dry ice, since it is able to hold the required temperature for much longer.
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Affiliation(s)
- V A Kozlova
- FSI National Research Center for Therapy and Preventive Medicine of the Ministry of Healthcare of the Russian Federation
| | - M S Pokrovskaya
- FSI National Research Center for Therapy and Preventive Medicine of the Ministry of Healthcare of the Russian Federation
| | - A N Meshkov
- FSI National Research Center for Therapy and Preventive Medicine of the Ministry of Healthcare of the Russian Federation
| | - O M Drapkina
- FSI National Research Center for Therapy and Preventive Medicine of the Ministry of Healthcare of the Russian Federation
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The Impact of Varying Cooling and Thawing Rates on the Quality of Cryopreserved Human Peripheral Blood T Cells. Sci Rep 2019; 9:3417. [PMID: 30833714 PMCID: PMC6399228 DOI: 10.1038/s41598-019-39957-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 02/06/2019] [Indexed: 12/11/2022] Open
Abstract
For the clinical delivery of immunotherapies it is anticipated that cells will be cryopreserved and shipped to the patient where they will be thawed and administered. An established view in cellular cryopreservation is that following freezing, cells must be warmed rapidly (≤5 minutes) in order to maintain high viability. In this study we examine the interaction between the rate of cooling and rate of warming on the viability, and function of T cells formulated in a conventional DMSO based cryoprotectant and processed in conventional cryovials. The data obtained show that provided the cooling rate is -1 °C min-1 or slower, there is effectively no impact of warming rate on viable cell number within the range of warming rates examined (1.6 °C min-1 to 113 °C min-1). It is only following a rapid rate of cooling (-10 °C min-1) that a reduction in viable cell number is observed following slow rates of warming (1.6 °C min-1 and 6.2 °C min-1), but not rapid rates of warming (113 °C min-1 and 45 °C min-1). Cryomicroscopy studies revealed that this loss of viability is correlated with changes in the ice crystal structure during warming. At high cooling rates (-10 °C min-1) the ice structure appeared highly amorphous, and when subsequently thawed at slow rates (6.2 °C min-1 and below) ice recrystallization was observed during thaw suggesting mechanical disruption of the frozen cells. This data provides a fascinating insight into the crystal structure dependent behaviour during phase change of frozen cell therapies and its effect on live cell suspensions. Furthermore, it provides an operating envelope for the cryopreservation of T cells as an emerging industry defines formulation volumes and cryocontainers for immunotherapy products.
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Wilczek P, Paulina G, Karolina J, Martyna M, Grazyna W, Roman M, Aldona M, Anna S, Aneta S. Biomechanical and morphological stability of acellular scaffolds for tissue-engineered heart valves depends on different storage conditions. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2018; 29:106. [PMID: 29971508 PMCID: PMC6028870 DOI: 10.1007/s10856-018-6106-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 06/14/2018] [Indexed: 06/08/2023]
Abstract
Currently available bioprosthetic heart valves have been successfully used clinically; however, they have several limitations. Alternatively, tissue-engineering techniques can be used. However, there are limited data concerning the impact of storage conditions of scaffolds on their biomechanics and morphology. The aim of this study was to determine the effect of different storage conditions on the biomechanics and morphology of pulmonary valve dedicated for the acellular scaffold preparation to achieve optimal conditions to obtain stable heart valve prostheses. Scaffold can then be used for the construction of tissue-engineered heart valve, for this reason evaluation of these parameters can determine the success of the clinical application this type of bioprosthesis. Pulmonary heart valves were collected from adult porcines. Materials were divided into five groups depending on the storage conditions. Biomechanical tests were performed, both the static tensile test, and examination of viscoelastic properties. Extracellular matrix morphology was evaluated using transmission electron microscopy and immunohistochemistry. Tissue stored at 4 °C exhibited a higher modulus of elasticity than the control (native) and fresh acellular, which indicated the stiffening of the tissue and changes of the viscoelastic properties. Such changes were not observed in the radial direction. Percent strain was not significantly different in the study groups. The storage conditions affected the acellularization efficiency and tissue morphology. To the best of our knowledge, this study is the first that attributes the mechanical properties of pulmonary valve tissue to the biomechanical changes in the collagen network due to different storage conditions. Storage conditions of scaffolds for tissue-engineered heart valves may have a significant impact on the haemodynamic and clinical effects of the used bioprostheses.
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Affiliation(s)
- Piotr Wilczek
- Heart Prosthesis Institute, Bioengineering Laboratory, Wolnosci 345A, 41-800, Zabrze, Poland.
| | - Gach Paulina
- Heart Prosthesis Institute, Bioengineering Laboratory, Wolnosci 345A, 41-800, Zabrze, Poland
| | - Jendryczko Karolina
- Heart Prosthesis Institute, Bioengineering Laboratory, Wolnosci 345A, 41-800, Zabrze, Poland
| | - Marcisz Martyna
- Heart Prosthesis Institute, Bioengineering Laboratory, Wolnosci 345A, 41-800, Zabrze, Poland
| | - Wilczek Grazyna
- Department of Animal Physiology and Ecotoxicology, Faculty of Biology and Environmental Protection, University of Silesia, Bankowa 9, 40-007, Katowice, Poland
| | - Major Roman
- Institute of Metallurgy and Materials Science, Reymonta 24, 30-059, Krakow, Poland
| | - Mzyk Aldona
- Institute of Metallurgy and Materials Science, Reymonta 24, 30-059, Krakow, Poland
| | - Sypien Anna
- Institute of Metallurgy and Materials Science, Reymonta 24, 30-059, Krakow, Poland
| | - Samotus Aneta
- Heart Prosthesis Institute, Bioengineering Laboratory, Wolnosci 345A, 41-800, Zabrze, Poland
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A study of cryogenic tissue-engineered liver slices in calcium alginate gel for drug testing. Cryobiology 2018; 82:1-7. [PMID: 29752974 DOI: 10.1016/j.cryobiol.2018.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/03/2018] [Accepted: 05/06/2018] [Indexed: 01/24/2023]
Abstract
To address issues such as transportation and the time-consuming nature of tissue-engineered liver for use as an effective drug metabolism and toxicity testing model, "ready-to-use" cryogenic tissue-engineered liver needs to be studied. The research developed a cryogenic tissue-engineered liver slice (TELS), which comprised of HepG2 cells and calcium alginate gel. Cell viability and liver-specific functions were examined after different cryopreservation and recovery culture times. Then, cryogenic TELSs were used as a drug-testing model and treated with Gefitinib. Cryogenic TELSs were stored at -80 °C to ensure high cell viability. During recovery in culture, the cells in the cryogenic TELS were evenly distributed, massively proliferated, and then formed spheroid-like aggregates from day 1 to day 13. The liver-specific functions in the cryogenic TELS were closely related to cryopreservation time and cell proliferation. As a reproducible drug-testing model, the cryogenic TELS showed an obvious drug reaction after treatment with the Gefitinib. The present study shows that the cryopreservation techniques can be used in drug-testing models.
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Kilbride P, Lamb S, Gibbons S, Bundy J, Erro E, Selden C, Fuller B, Morris J. Cryopreservation and re-culture of a 2.3 litre biomass for use in a bioartificial liver device. PLoS One 2017; 12:e0183385. [PMID: 28841674 PMCID: PMC5572048 DOI: 10.1371/journal.pone.0183385] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 07/28/2017] [Indexed: 12/29/2022] Open
Abstract
For large and complex tissue engineered constructs to be available on demand, long term storage using methods, such as cryopreservation, are essential. This study optimised parameters such as excess media concentration and warming rates and used the findings to enable the successful cryopreservation of 2.3 litres of alginate encapsulated liver cell spheroids. This volume of biomass is typical of those required for successful treatment of Acute Liver Failure using our Bioartificial Liver Device. Adding a buffer of medium above the biomass, as well as slow (0.6°C/min) warming rates was found to give the best results, so long as the warming through the equilibrium melting temperature was rapid. After 72 h post thaw-culture, viable cell number, glucose consumption, lactate production, and alpha-fetoprotein production had recovered to pre-freeze values in the 2.3 litre biomass (1.00 ± 0.05, 1.19 ± 0.10, 1.23 ± 0.18, 2.03 ± 0.04 per ml biomass of the pre-cryopreservation values respectively). It was also shown that further improvements in warming rates of the biomass could reduce recovery time to < 48 h. This is the first example of a biomass of this volume being successfully cryopreserved in a single cassette and re-cultured. It demonstrates that a bioartificial liver device can be cryopreserved, and has wider applications to scale-up large volume cryopreservation.
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Affiliation(s)
- Peter Kilbride
- Asymptote, General Electric Healthcare, Cambridge, United Kingdom
- Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College London, London, United Kingdom
- * E-mail:
| | - Stephen Lamb
- Asymptote, General Electric Healthcare, Cambridge, United Kingdom
| | - Stephanie Gibbons
- Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College London, London, United Kingdom
| | - James Bundy
- Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College London, London, United Kingdom
| | - Eloy Erro
- Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College London, London, United Kingdom
| | - Clare Selden
- Institute for Liver and Digestive Health, Royal Free Hospital Campus, University College London, London, United Kingdom
| | - Barry Fuller
- Department of Surgery, Royal Free Hospital Campus, University College London, London, United Kingdom
| | - John Morris
- Asymptote, General Electric Healthcare, Cambridge, United Kingdom
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Kilbride P, Mahbubani KT, Saeb-Parsy K, Morris GJ. Engaging Cold to Upregulate Cell Proliferation in Alginate-Encapsulated Liver Spheroids. Tissue Eng Part C Methods 2017; 23:455-464. [PMID: 28727981 DOI: 10.1089/ten.tec.2017.0131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
For many years, the impact of hyper- and hypothermia on mammalian cells has been examined. With the exception of short, low temperature storage, which has uses in areas such as preservation for transplantation or regenerative medicine, advantages for the use of low temperature treatment in hepatocytes have not been previously reported. We have observed that alginate-encapsulated HepG2 liver spheroids that are cryopreserved or experience a cold reduction in temperature (≤10°C) for periods between 1 and 90 min display an enhanced cell proliferation during culture 7-16 days post-treatment compared with untreated samples. Following 8-12 days post-treatment, alginate-encapsulated liver spheroids experienced a cell density of 1.71 ± 0.35 times that of control samples (p < 0.001). This effect occurred in samples with a variety of cold treatments. This low temperature treatment offers a simple method to rapidly increase cell proliferation rates for extended culture systems, such as bioartificial liver devices. This would allow the manufacture of required biomass more rapidly, and to a higher cell density, reducing final required biomass volume. This could enable bioartificial liver devices to be prepared more cheaply, making them a more cost effective treatment.
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Affiliation(s)
| | - Krishnaa T Mahbubani
- 2 Department of Surgery, University of Cambridge , Cambridge, United Kingdom .,3 Cambridge NIHR Biomedical Research Centre , Cambridge, United Kingdom
| | - Kourosh Saeb-Parsy
- 2 Department of Surgery, University of Cambridge , Cambridge, United Kingdom .,3 Cambridge NIHR Biomedical Research Centre , Cambridge, United Kingdom
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Stacey GN, Connon CJ, Coopman K, Dickson AJ, Fuller B, Hunt CJ, Kemp P, Kerby J, Man J, Matejtschuk P, Moore H, Morris J, Oreffo ROC, Slater N, Ward S, Wiggins C, Zimmermann H. Preservation and stability of cell therapy products: recommendations from an expert workshop. Regen Med 2017; 12:553-564. [DOI: 10.2217/rme-2017-0073] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
If the field of regenerative medicine is to deliver therapies, rapid expansion and delivery over considerable distances to large numbers of patients is needed. This will demand efficient stabilization and shipment of cell products. However, cryopreservation science is poorly understood by life-scientists in general and in recent decades only limited progress has been made in the technology of preservation and storage of cells. Rapid translation of new developments to a broader range of cell types will be vital, as will assuring a deeper knowledge of the fundamental cell biology relating to successful preservation and recovery of cell cultures. This report presents expert consensus on these and other issues which need to be addressed for more efficient delivery of cell therapies.
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Affiliation(s)
- Glyn N Stacey
- UK Stem Cell Bank, Division of Advanced Therapies, NIBSC, South Mimms, Hertfordshire, UK
| | - Che J Connon
- Institute of Genetic Medicine, University of Newcastle, Newcastle upon Tyne, UK
| | - Karen Coopman
- Chemical Engineering, Loughborough University, Loughborough, UK
| | - Alan J Dickson
- Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
| | - Barry Fuller
- Department of Surgery, University College London, London, UK
| | - Charles J Hunt
- UK Stem Cell Bank, Division of Advanced Therapies, NIBSC, South Mimms, Hertfordshire, UK
| | - Paul Kemp
- Intercytex Ltd & HairClone, Manchester, UK
| | - Julie Kerby
- Cell Therapy Manufacturing Development, Pfizer, Cambridge, UK
| | - Jennifer Man
- UK Stem Cell Bank, Division of Advanced Therapies, NIBSC, South Mimms, Hertfordshire, UK
| | - Paul Matejtschuk
- Standardisation Science, National Institute for Biological Standards and Control (NIBSC) a centre of the MHRA, South Mimms, Hertfordshire, UK
| | - Harry Moore
- Department of Biomedical Sciences, University of Sheffield, Sheffield, UK
| | | | - Richard OC Oreffo
- Centre for Human Development, Stem Cells & Regeneration, University of Southampton, Southampton, UK
| | - Nigel Slater
- The Bioscience Engineering Group, University of Cambridge, Cambridge, UK
| | | | - Claire Wiggins
- National Health Service – Blood & Transplant, Watford, UK
| | - Heiko Zimmermann
- Fraunhofer-Institute for Biomedical Engineering, Sulzbach, Germany
- Department of Molecular & Cellular Biotechnology/Nanotechnology, Saarland University, Saarbrücken, Germany
- Department of Marine Sciences, Universidad Católica del Norte, Antafogasta/Coquimbo, Chile
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Kilbride P, Morris GJ. Viscosities encountered during the cryopreservation of dimethyl sulphoxide systems. Cryobiology 2017; 76:92-97. [PMID: 28414045 DOI: 10.1016/j.cryobiol.2017.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 04/01/2017] [Accepted: 04/13/2017] [Indexed: 11/27/2022]
Abstract
This study determined the viscous conditions experienced by cells in the unfrozen freeze concentrated channels between ice crystals in slow cooling protocols. This was examined for both the binary Me2SO-water and the ternary Me2SO-NaCl-water systems. Viscosity increases from 6.9 ± 0.1 mPa s at -14.4 ± 0.3 °C to 958 ± 27 mPa s at -64.3 ± 0.4 °C in the binary system, and up to 55387 ± 1068 mPa s at -75 ± 0.5 °C in the ternary (10% Me2SO, 0.9% NaCl by weight) solution were seen. This increase in viscosity limits molecular diffusion, reducing adsorption onto the crystal plane. These viscosities are significantly lower than observed in glycerol based systems and so cells in freeze concentrated channels cooled to between -60 °C and -75 °C will reside in a thick fluid not a near-solid state as is often assumed. In addition, the viscosities experienced during cooling of various Me2SO based vitrification solutions is determined to below -70 °C, as is the impact which additional solutes exert on viscosity. These data show that additional solutes in a cryopreservation system cause disproportionate increases in viscosity. This in turn impacts diffusion rates and mixing abilities of high concentrations of cryoprotectants, and have applications to understanding the fundamental cooling responses of cells to Me2SO based cryopreservation solutions.
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Affiliation(s)
- P Kilbride
- Asymptote Ltd., St John's Innovation Centre, Cowley Road, Cambridge, CB4 0WS, United Kingdom.
| | - G J Morris
- Asymptote Ltd., St John's Innovation Centre, Cowley Road, Cambridge, CB4 0WS, United Kingdom
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