Cryopreservation equipment

Ron Hrstka ronald-hrstka at
Fri Nov 24 17:37:52 EST 1995

deanh at (Dean Hewish) wrote:
> Years ago I saw an advertisment for a simple apparatus for slow-cooling
> cells during cryopreservation. It was a plastic container that held the
> vials surrounded by a chamber with a liquid -isopropanol, I think, to
> modulate the cooling rate. I think that the whole container was placed
> in the freezer to initiate cooling. 
> We have been having trouble geting reproducable cooling rates and I
> would like to try this system out but I have lost the advertisment.
> Has anyone out there used this system or know who the manufacturer is?
> Thanks,
> Dean R. Hewish
> Cell biologist and Flow Cytometrist
> CSIRO Division of Biomolecular Engineering
> Parkville, Victoria, Australia

Nalgene makes the "Cryo 1C Freezing Container" catalog no. 5100-0001 
which sounds like what you are describing.  It does use isopropanol
and the company's claim is that it provides a more steady rate of 
temperature decline than that of a styrofoam container.  I have four 
of these units and have used them for two years for freezing embryonic
stem cells and fibroblast cells.  

Until recently I took the company at its word--both in its claims and
its instructions.  The instructions for the unit call for the initial
placement of vials into the container when it is at room
temperature.  This always bothered me because I understood that the 
cells would be less harmed by the cryoprotectant in the freezing 
solution if it was kept ice cold.  It seemed that the best survival
would occur if the cells began at a cold temperature and then have a
steadily declining temperature.  If Nalgene's directions are followed,
the cells will initially be placed into ice cold freeze solution, but 
the temperature will rise when placed into the room temperature
container which has a much greater mass.  I thought it better to keep
container in the refrigerator until immediately prior to use.

I finally did a comparison of freezing methods recently.  I compared 
using a room temperature container, a refrigerated container, and a 
standard styrofoam box.  Other conditions were identical.  All three 
containers were placed in a -70C freezer.  The results I got were 
consistent and dramatic.  By far the best survival was achieved in the
styrofoam box, the worst was using the Nalgene unit per its directions
of using it at room temperature.  The initially cold Nalgene container
yielded an intermediate survival rate compared to the other two 

Ron Hrstka
University of Iowa Hospital
Dept. Ob-Gyn, MRF 585
Iowa City, IA 52242

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