X-Message-Number: 13114
Date: Wed, 19 Jan 2000 13:44:59 -0800 (PST)
From: Doug Skrecky <>
Subject: sugars

In Message #13106 Thomas Donaldson wrote:

> First of all, no sugar so far known has helped with suspension down to
> temperatures close to or below that of liquid nitrogen.
  I've looked into the use of sugars myself, particularly since they 
possess a high glass transition, which could eliminate the need for
liquid nitrogen storage if used by themselves. Much smaller amounts of
sugars added to low molecular weight cryoprotectants such as ethylene
glycol greatly reduce the toxicity of the resulting solution. 
  Unfortunately sugars molecules are so large that they permeate into 
tissue too slowly to be usable. Some sugar alcohols such as glycerol
also can be used to reduce ethylene glycol toxicity, and since glycerol
can slowly penetrate tissue, its use makes sense. Erythritol looks to
be the only sugar alcohol, than might possibly be used by itself to 
enable the use of dry ice in place of liquid nitrogen for a storage
medium. This has a much higher cell membrane permeability than even
higher molecular weight sugars, and sugar alcohols such as sorbitol.
However this is slower than even glycerol, and use of permeation 
enhancing techniques such as ultrasound would be a requirement
significant tissue penetration in an acceptible time frame.

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=13114