X-Message-Number: 1446
Date: 14 Dec 92 21:25:03 EST
From: Garret Smyth <>
Subject: Re: Cryoprotectant Issues

Its a while since I did chemistry, but I feel that a suspension would not
be very effective as a cryooprotective. Perhaps an emulsion might be
better, but I think a straight mixture  might be best. An ideal
cryoprotectant, as far as I am aware, has to penetrate the blood brain
barrier in order to get into the cell bodies. A cryoprotectant must be
soluable in polar as well as non polar solvents, hence able to mix into
water and lipid (membranes), so that they can cross cell membranes, and
dispalce water within. They must also have the effect of supressing the
freezing point. 

I Like the DMSO/glycerol idea, though. If DMSO is too penetrative, and
glycerol causes too much dehydration, then a mixture of the 2 might be
the answer. The aspect of mixtures is they have an additive combination
of the properties of their components, rather than any new properties.
The better vitrification combinations are mixtures. Doesn't Pierre
Boutron have a mixture that shows promise (can't off hand remember its
name, but I'll look it up.) 

I think that the term "osmotically opened", when used in reference to the
blood brain barrier means that the right chemical conditions will cause
it it to be much less selective about hte size of the molecules it lets
through.

Garret

PS Could people use fewer TLAs. They make typing marginally easier, but
make reading a lot harder.

PPS A TLA is a Three Letter Acronym.

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