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