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. Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=1446