X-Message-Number: 8433
Date: Fri, 1 Aug 1997 05:30:13 -0700 (PDT)
From: Doug Skrecky <>
Subject: Re: CryoNet #8429 - #8432

In Message #8429 Brian Wowk <> wrote:
> 	About adonitol in particular, adonitol (1,2,3,4,5 penta-
> hydroxypentane) is a huge molecule that costs $2 per gram.
> Although I haven't consulted Doug's permeability reference
> yet, it's almost certainly going to be less permeant and
> more viscous than glycerol.  And glycerol is already almost
> intolerably viscous and non-permeant for cryoprotection by
> perfusion (as distinct from cryoprotection of cell suspenstions
> in solution).
> 
Adonitol is indeed more viscous than glycerol. That's the inevitable price
you have to pay for cryoprotection that is stable (or glassy) at
relatively high temperatures. Adonitol has a molecular weight of 152,
while glycerol's is 92.09. Adonitol perfuses well for a molecule of its
size because its cross section is no larger than that of glycerol, so it
can pass through pores in cell membranes. Sorbitol has a molecular weight
of 182.17 and unfortunately has a larger cross section, so it diffuses
very slowly. However at least sorbitol is cheap. I will make some
inquiries to see what the best price for adonitol is.

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