Cell Cryopreservation
Cell Cryopreservation

Cryopreservation is the use of low temperatures to preserve structurally intact living cells. Cells are cryopreserved to avoid loss by contamination, to minimize genetic change in continuous lines and to avoid transformation in finite lines.

Successful cryopreservation of cells depends on optimal freezing conditions, storage, and proper cell thawing techniques. A standardized and reproducible protocol must be followed, although each protocol may require optimization for a given cell type or line, to achieve maximum viability upon thaw.

 

Mammalian cells that are cryopreserved include immortalized cell lines, primary cells isolated from tissues and stem cells. Mammalian cells are best frozen in the presence of a cryopreservant such as DMSO or glycerol, with a freeze rate of 1°C/minute to avoid detrimental ice crystal formation as water within the cell is frozen.

Cell Preparation

Cryogenic vial preparation is typically performed under aseptic conditions in a cell culture hood. Cell suspensions are typically kept cold (0.5 to 4.0℃) which requires the use of ice outside the hood or an ice-free cooling unit inside the hood. The CoolBox ice-free cooling workstations can be used inside a sterile hood environment and will keep up to 48 cryogenic vials cold (0.5 to 4℃) for >16 hours.

The thermo-conductive properties of the cooling core inside the CoolBox and the cryogenic vial CoolRack holder ensure uniform temperature distribution to all vials during the process. CoolBox does not require ice, electricity or batteries.

Cell Freezing

Optimal cell cryopreservation requires a controlled freezing rate of -1℃/minute for most types of cells and choosing the right freezing method is crucial. CoolCell alcohol-free cell freezing containers provide controlled rate freezing in a -80℃ freezer. Current methods that utilize isopropanol-based freezing containers and styrofoam boxes do not provide uniform freezing rates to all vials and/or may not be reproducible.

CoolCell alcohol-free cell freezing containers provide a cost effective means of reproducibly conducting the cell freezing process in a -80℃ freezer or with a portable dry ice temperature stability system. CoolCell freezing containers provide uniform, consistent and reproducible cell cryopreservation.

The Problem

 

Alcohol-based cell freezing containers require a constant fresh supply of 100% isopropyl alcohol to maintain an approximate -1ºC/minute freeze rate, resulting in on-going purchase cost and hazardous waste disposal.

Concentric rings of cryogenic vials inhibits uniform cryogenic vial freezing as heat from inner vials must pass through outer vials to escape the vessel.

Alcohol container
The Solution
CoolCell Graph

 

 

CoolCell alcohol-free cell freezing containers do not require any alcohol or other fluids to control the -1ºC/minute freeze rate. Insulative outer materials and inner alloy core, combined with radially-symmetric vial placement regulate a uniform heat removal rate for all vials. Freeze runs are consistent and highly reproducible.

  • How do CoolCell containers work?

    CoolCell freezing containers are passive devices that provide a controlled -1℃/minute freeze rate to all cryogenic vials when placed in a -80℃ freezer. CoolCell containers do not require isopropanol or any fluids - the design and materials regulate heat removal and provide uniform and reproducible freezing to all vials.

    • Highly insulative cross-linked closed-cell polyethylene foam has superior material properties at cryogenic temperatures
    • Radially-symmetric vial distribution ensures uniform heat removal for each vial
    • Solid alloy thermal core fine-tunes and balances the freezing profile
    • Durable single-block base construction provides long life-cycle without change in performance
    CoolCell How It Works
  • How do CoolCell containers compare to other freezing methods?
    CoolCell Containers Styrofoam Containers Isopropanol-Based Container
    Consistent -1˚C/minute freeze rate
    Freeze rate uniform to all vials
    Alcohol-free; no ongoing cost, maintenance or waste
    Reproducible freezing profiles
    5-10 minute wait period between freeze runs (allows 2 freeze runs per day)
    Optimal for pluripotent stem cell recovery (see above)
    Difficult to document rate of cell freezing
    Unstandardized
    Styrofoam containers can vary greatly in size, geometry, density and structure
    Not reproducible



     
    Stated freeze rate of -1°C/minute
    Freeze rate varies based on vial position
    Continuous isopropanol replenishment, cost and waste
    Isopropanol is a variable in each freeze run hindering consistent reproducibility
    Long wait periods between freeze runs

     
Reviews

"The device is elegant in its simplicity and ease of use and offers researchers a method to cryopreserve cells in a standardized fashion with great reproducibility and little variability in performance."
- Kevin Grady, ATCC

"We run a registry, in which large amounts of PBMCs are processed for long-term cyropreservation. After testing the CoolCell out, we found slightly better cell viability (>90%) than our current cell freezing containers, and there is no Isopropanol waste generated. Overall, the CoolCell has proven to us to set a new bar in cryopreservation."
- Rohit Gupta, Stanford University

"The CoolCell is more efficient and easier to use than the Mr. Frosty. Not needing to add isopropyl, the lack of a screw top, and not having downtime after removing it from the -80° makes freezing cells a lot easier. I plan on only purchasing the CoolCell in the future."
- Matt Donne, UCSF Stem Cell Lab

"Purely altruistically, I wanted to mention that one big advantage of the CoolCell is that you can use dry ice to do your freezing if you don't have a -80. I spent nearly a year getting terrible viability-recovery on cell freezing with dry ice (in an alcohol device) followed by storage in LN2, and this on HeLa cells which aren't exactly hard to store. I then bought a CoolCell and now I can just use standard cryo-preservation techniques (DMSO, 20% NBS) and get nearly 100% viability on thawing."
- Sam Knight, Ceramisphere (Australia)

References

Shu Z, Kang X, Chen H, Zhou X, Purtteman J, Yadock D, Heimfeld S, and Gao D, Development of a Reliable, Low-cost, Controlled Cooling Rate Instrument for the Cryopreservation of Hematopoietic Stem Cells. Cytotherapy. 2010.