Ok, I just looked up the freezing point depression formula which is ΔTf = Kf * m * i,
and according to the formula, even at the highest recorded blood sugar level of 311.3 mmol/L which caused a coma, it would only lead to a freezing point of about -0.6 C.
Also, I am still wondering how long preservation would work at higher temperatures, it seems a lot of problems occur when trying to lower it to -196.
However, at this point I think the most leveraged approach to mitigating toxicity would be determining biochemical mechanisms of toxicity rather than more empirical study of cryoprotectant composition. Toxicity has already been studied empirically in cryobiology for 60 years. It's time to learn what's really going on.
I agree, and it seems the only real way to do this would be with computer simulations. Luckily, computational biology and computational molecular biophysics
are rapidly growing fields. Has 21 Century Medicine tried to use computer simulations?
There are only a few hundred compounds of low enough molecular weight (<100) to penetrate cell membranes easily. Most of these compounds are disqualified by excessive hydrophobicity (which correlates with toxicity) or poor solubility. The design space for intracellular cryoprotectants is very small.
According to what I have read, the size limit is higher:
(By the way, 1 Da = 1 g/mol.)
Unfortunately, the Anti-Freeze Proteins (AFPs) are all at least 1000 Da.
To get around this problem, maybe a virus could be created which would infect cells with genetic material which would then produce AFPs, inside the cell itself.
This would massively increase the design space, allowing billions of possibilities for cryoprotectants rather than hundreds. Although virus drug delivery is far-off, fortunately, it is the subject of intense research link
because of its applications in cancer drug delivery, unlike the cancer researchers though, who are trying to target specific cells with their viruses, cryonics would not need specificity, it would just need something that would pass the genetic material to all cells, which would then produce the proteins for cryoprotection in the cell.
You might also be able to use prions to infect the cells with cryoprotectants.
link has a wide variety of interesting ways to get larger molecules through the blood brain barrier.
An interesting link: http://www.scienceda...81222081214.htm
(The source journal article
pdf is attached)
Edited by nanothan, 24 November 2010 - 11:31 PM.