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#cryopreservation

7 public questions tagged with this topic.

Animal Tissue Culture 2

The temperature of liquid nitrogen used for cryopreservation is:

Liquid nitrogen provides ultralow storage temperature of -196°C at atmospheric pressure, close to its boiling point. At this temperature, kinetic energy of molecules becomes extremely low, effectively halting all biochemical reactions, enzymatic activity, solute diffusion, and ice recrystallization processes. Cells suspended in DMSO-containing freezing medium enter glassy state preventing further ice growth. Long-term viability preserved for decades to theoretically indefinitely. Mechanical ultra-low freezers at -80°C slow metabolism but do not fully arrest chemical reactions; free radical accumulation and gradual ice crystal growth over months reduce viability, making -80°C suitable only for temporary holding. Storage can be in liquid phase immersing vials directly achieving -196°C or vapor phase at -150°C to -180°C reducing risk of cross-contamination between leaky vials and transmission of adventitious agents. Inventory systems with alphanumeric racking, cryovial labeling resistant to nitrogen, and continuous temperature alarms with liquid nitrogen level monitors ensure security of master and working cell banks including valuable induced pluripotent stem cells.

Ref: ATCC Animal Cell Culture Guide Liquid Nitrogen -196°C arrests metabolism; Freshney Ch.22 Vapor vs liquid phase storage principles.

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Animal Tissue Culture 2

Cryopreservation of animal cells commonly uses:

Cryopreservation of mammalian cells routinely employs dimethyl sulfoxide as penetrating cryoprotectant at 5-10% concentration. DMSO is small amphipathic molecule freely crossing lipid bilayer, replacing intracellular water and disrupting hydrogen bonding network required for ice lattice formation. During controlled slow cooling at -1°C per minute achieved using isopropanol containers like Mr. Frosty or programmable freezers, extracellular ice forms first creating osmotic gradient that draws water out of cells dehydrating them. DMSO lowers freezing point, promotes vitrification where residual intracellular water transitions to amorphous glass rather than sharp damaging crystals that would shear membranes, organelles and chromosomes. DMSO also stabilizes proteins through preferential exclusion. At ambient temperature DMSO exhibits cytotoxicity and can trigger differentiation of hematopoietic lines, so after thawing rapid dilution in large volume medium reduces concentration below 1%. Glycerol penetrates slower favoring insect and embryonic stem cells, while ethanol and formaldehyde are lethal and unsuitable. DMSO thus became standard in ATCC and cell bank protocols.

Ref: Freshney Ch.22 Cryopreservation DMSO prevents intracellular ice; Mazur Science 1984 kinetics of water loss and vitrification by DMSO.

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Basic Applied Biology

Temperature of liquid nitrogen used in cryopreservation is:

Liquid nitrogen at atmospheric pressure liquefies at minus 196 Celsius, providing ultra-low temperature environment where molecular diffusion essentially ceases, enzymatic catalysis halts, aqueous solutions enter amorphous glassy state rather than crystalline ice if cooling rapid enough, and cellular aging arrested for decades to centuries. This temperature lies well below glass transition of water-cryoprotectant mixtures around minus 130 Celsius where dangerous devitrification and ice recrystallization occur, ensuring stability during long-term storage. Freezers at minus 80 Celsius or minus 20 Celsius permit residual molecular motion, slow enzymatic degradation, ice crystal growth over months and pH shifts from eutectic crystallization, insufficient for preservation of master cell banks. Rapid immersion of cryovials containing DMSO-protected cells into liquid nitrogen or vapor phase achieves vitrification, while retrieval demands rapid warming in 37 Celsius water bath to avoid transient passage through damage window. Safety mandates cryogloves, face shield and use of O-ring sealed vials to prevent liquid nitrogen entry which can cause explosion upon thawing. International repositories ATCC and ECACC maintain master cell banks at minus 196 Celsius under Good Manufacturing Practice to ensure genetic stability and sterility.

Ref: Mazur Journal General Physiology 1984 cryobiology principles; ATCC cryopreservation guide LN2 minus 196; Alberts cell storage methods.

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Basic Applied Biology

Cryoprotectant commonly used for animal cells is:

Cryopreservation enables essentially indefinite storage of mammalian cell lines and primary cells by arresting biochemical reactions at cryogenic temperatures, but prevention of lethal intracellular ice formation crucial. Dimethyl sulfoxide at 5 to 10 percent volume per volume emerged as standard cryoprotectant for most animal cells due to rapid membrane permeability coefficient 10^-5 cm per second, colligative depression of freezing point, ability to replace water molecules via hydrogen bonding and promotion of vitrification rather than crystallization that would mechanically puncture organelles and plasma membrane. During controlled slow cooling at minus 1 Celsius per minute achieved by isopropanol-filled containers Mr Frosty, DMSO reduces eutectic phase formation, limits solute concentration injury described by Mazur two-factor hypothesis balancing ice formation versus solute toxicity, stabilizes phospholipid bilayers and cytoskeleton. Compared to glycerol which permeates slower favored for insect Sf9 cells and some stem cells, DMSO offers faster equilibration but exhibits cytotoxicity at concentrations above 10 percent and temperature above 4 Celsius, necessitating quick addition at chilled state and rapid dilution with serum-containing medium post-thaw to sustain recovery above 80 percent. Ethanol and formaldehyde are toxic fixatives unsuitable for viability preservation.

Ref: Pegg Principles of Cryopreservation 2015; Freshney Ch freezing and cryopreservation; PubMed cryoprotectant toxicity PMID 21846505.

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Biosphere reserve & Wild life sancturies

Cryopreservation is carried out at

Cryopreservation ensures long-term conservation by storing viable cells, tissues, gametes, embryos, seeds, and pollen at ultra-low temperature where metabolism essentially halts but viability retained upon thawing. Standard method uses liquid nitrogen at -196°C boiling point, with slow freezing or vitrification using cryoprotectants dimethyl sulfoxide DMSO and glycerol preventing intracellular ice crystal damage. Applications include preservation of endangered plant germplasm at NBPGR New Delhi, animal gamete biobanking at LaCONES Hyderabad, and microbial culture collections supporting future biotechnology. Knowledge of this distribution aids in understanding endemism patterns and UNESCO heritage site designations across India.

Ref: NBPGR Gene Bank Manual Cryopreservation -196°C; NCERT Biotechnology Principles Cryoprotectants

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