MadSci Network: Cell Biology
Query:

Re: How DMSO protects cells upon freezing?

Date: Thu Feb 22 19:46:35 2007
Posted By: Kathleen Xie, Undergrad, Biology, MIT
Area of science: Cell Biology
ID: 1172145098.Cb
Message:

Question: How DMSO protects cells upon freezing?
Hello,

The quick and dirty answer is: 

As the suspension of cells freezes, ice crystals form. These ice crystals
can puncture the plasma membrane, leading to cell death. DMSO protects the
cells by 1) partially solublizing the membrane so that it is less prone to
puncture, and 2) interrupting the lattice of the ice, so that fewer
crystals form.

(Unfortunately, DMSO is also toxic for the cells (it partially solublizes
the membrane, after all), so when you thaw cells, it's important to do it
quickly and get them out of DMSO as soon as possible).

You can also substitute glycerol for DMSO, and bacteria are often stored in
glycerol at -80C (you have probably heard these stocks refered to as
"glycerol stocks"). Substances like glycerol and DMSO are generally called
cryoprotectants.

If you're interested in a more rigorous explanation for the various factors
contributing to cell damage during freezing, here is a very extensive and
thorough review on cryopreservation: Mazur, P. Cryobiology: The Freezing of
Biological Systems. Science, 168: 939-949 (1970).

The following are two classic papers:

Lovelock, J. E. and Bishop, M. W. H. Prevention of Freezing Damage to
Living Cells by Dimethyl Sulphoxide. Nature, 183: 1394-1395 (1959).
	Discovery that DMSO can be used as a cryoprotectant.

Polge, C., Smith, A. U., and Parkes, A. S. Nature 184, 666 (1949).
	The original, famous trio who (serendipitously) discovered that glycerol
can be used as a cryoprotectant.

And there is also an online textbook on cryobiology available here: http://www.ucalgary.ca/~kmuldrew/cryo_course/course_outline.html

Kathy Xie


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