Cryoprotectants: the essential antifreezes to protect life in the frozen state. CryoLetters

University Department of Surgery, Royal Free and University College Medical School, London NW3 2QG, UK.
Cryo letters (Impact Factor: 1.14). 11/2004; 25(6):375-88.
Source: PubMed


In the fifty years since the establishment of the cryoprotective effect of glycerol, cell banking by cryopreservation has become routine in many areas of biotechnology and medicine. Cryoprotectant addition has become a rather mundane step within the overall protocol. However, for future advances in cryobiology and to meet new challenges in the clinical use of cryopreserved cells or tissues, it will be essential to have an understanding of the development and current status of the biological and chemical knowledge on cryoprotectants (CPA). This review was undertaken to outline the history of CPA use, the important properties of CPA in relation to freezing damage, and what can be learnt from natural freezing-tolerant organisms. The conflicting effects of protection and toxicity resulting from use of CPA are discussed, and the role of CPA in enhancing glassy states in the emerging field of vitrification are also set out.

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    • "It should be noted that glycerol is easily digested, non-toxic and is recognized as safe by food and drug administration. At low temperatures , glycerol may serve as penetrating cryoprotectant that inhibits the growth of ice crystals (Fuller 2004). Due to its strong interactions with water in the plant system, some parts of water become unfreezable or bound. "

    Food and Bioprocess Technology 10/2015; DOI:10.1007/s11947-015-1607-8 · 2.69 Impact Factor
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    • "In particular, injury events can derive from dehydration due to extracellular ice formation, and/or from intracellular ice formation; these events strongly compromise the integrity of the plasmatic membrane. Slow rate-controlled freezing (typically around 1 °C) can help in reducing damages connected to the development of an osmotic pressure gradient across the membrane and to the mechanical stress of extracellular ice [2] [3] [4] [5] [6]. In fact, during slow cooling cells with less permeable membranes can dehydrate fast enough to avoid rupture; in this dehydration process the formation of intracellular ice is largely reduced. "
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    ABSTRACT: In the present study, FTIR spectroscopy was used to monitor the freeze-thaw cycle of two cellular lines (HuDe and Jurkat) suspended in three different media: phosphate buffer solution (PBS); dimethylsulfoxide (DMSO)/PBS solution at 0.1 DMSO molar fraction; and CryoSure (0.1 DMSO molar fraction PBS solution+dextran 5% w/v) solution. The Trypan Blue test was also applied before freezing and after thawing each cell sample to estimate the recovery of membrane integrity after thermal treatment, and correlate this datum with spectroscopic results. By following the temperature evolution of two different spectral components (the libration and bending combination mode νc(H2O) at 2000-2500cm(-1), and the methylene symmetric stretching vibration νsym(CH2) at about 2850cm(-1)) in the -120÷28°C range, we evidenced the main transition of lipid membrane in connection with cell dehydration, as induced by ice formation in the extracellular medium. In particular, in DMSO/PBS and CryoSure samples we observed a transition to a more rigid state of the lipid membrane together with an increased amount of non-freezable water in the extracellular medium; these results are connected to the role of DMSO as a cryoprotective agent irrespective of the nature of cell type. Copyright © 2015 Elsevier B.V. All rights reserved.
    Biophysical chemistry 08/2015; DOI:10.1016/j.bpc.2015.08.001 · 1.99 Impact Factor
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    • "This suggests EY also has a contraceptive effect in the hen genital tract [29]. Unfortunately, the true mechanisms underlying the contraceptive effects of both GLY and EY remain unknown [1] [29]. The sperm–egg penetration (SP-holes) assay, however , could be useful in investigating them. "
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    ABSTRACT: Glycerol (GLY) and egg yolk (EY) are good cryoprotectants of avian and mammalian sperm, but in birds, they strongly inhibit the eventual fertilization of ova. Using the sperm penetration (SP-holes) assay and fertility trials, the present study investigates (1) the possible mechanism by which this contraceptive effect occurs in chickens and (2) the maximum concentrations of GLY and EY tolerated by fresh rooster sperm. Seventy Black-Barred Andaluza hens (five per treatment) were inseminated four times (twice per week) with 0.1 mL of fresh semen from roosters of the same breed diluted 1:1 (v:v) with Lake and Ravie medium containing different concentrations of GLY or EY. No adverse effects on acrosome integrity, sperm motility, or viability were seen with any concentration of GLY or EY. The number of SP-holes on perivitelline layer samples taken from above the germinal disc became progressively lower at GLY concentrations of 1.5% or greater (P > 0.05). No holes caused by sperms were seen in unfertilized eggs. The corresponding fertility results showed similar reductions when the GLY concentration was 1.5% or greater. No changes in the number of SP-holes were seen with increasing EY concentrations (0%-7.5%), nor were any differences in fertility observed, except for a reduction when 15% EY was used. The results therefore reveal that GLY affects the transit of sperms through the oviduct in their attempt to reach the infundibulum area, limiting their access to the ovum perivitelline layer. Egg yolk had no such effect, nor did it influence acrosome reaction capacity; its mechanism of contraceptive action therefore remains unknown. The maximum GLY and EY concentrations tolerated by the rooster sperm were 0.75% and 7.5%, respectively. Copyright © 2015 Elsevier Inc. All rights reserved.
    Theriogenology 02/2015; 83(9). DOI:10.1016/j.theriogenology.2015.02.002 · 1.80 Impact Factor
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