X-Message-Number: 1016
Newsgroups: sci.cryonics
From:  (Perry E. Metzger)
Subject: Re: Ice crystal damage 
References: <>
Date: Fri, 17 Jul 1992 13:30:23 GMT

In article <> 
tolman% (Kenneth Tolman) writes:

>  One of the major concerns for current cryonics is ice crystal damage.  How
>could this damage be lessened?

Cryoprotectants to eliminate crystal formation.

>  The real question might be- why do ice crystals cause so much damage? I
>presume it is because it fits into a regular lattice- which has great
>strength and only allows for particular bonding formations.

No, thats not specifically the problem. I can describe it in much
simpler terms -- ice crystals form sharp structures that rupture cell
membranes and other subcellular structures as they grow.

>  Would a regular surfactant alleviate this crystal formation?  Maybe try
>freezing some water with soap in it.  

Soapy water does freeze, and I shudder to think of what would happen
to a patient with "Ivory Liquid" injected into them. Some soaps do
contain glycerine, but thats hardly an endorsement for them as a

>  What are the active sites of enzymes which mitigate ice crystal
>  damage?

There are no "enzymes" to mitigate ice crystal damage any more than
there are enzymes that could mitigate damage from a large dagger
shoved through your heart. Some organic molecules do indeed form
nucleation sites for ice crystal formation, but I doubt that it would
be a good idea to nuke most of your vital structures with enzymes.

>  As I implied in another posting- the best form of cryoprotectant would be
>enzymes produced by ones OWN cells.

There is no mechanism I can think of that would allow enzymes per se
to act as cryoprotectants. Cryoprotectants tend to be things like
glycerol that don't freeze well and inhibit water from freezing, too.
Think of it as antifreeze.

>That is, one would have a slight
>genetic engineering to produce the enzyme which would exist within you 
>during your whole life, and when it came time for suspension they would 
>maybe only have to do a few minor operations.  There would be no chemical
>trauma whatsoever......

What good would this do for existing patients?

>  It may be that the relative temperature change affects the ice crystal
>formation.  Thus, a slow and steady cooling may actually encourage ice
>damage (much as in simulated annealing), whereas a rapid cool off may
>inhibit massive ice structure formation.

Rapidly cool something as large as a human body, and the temperature
differential between the surface and core will cause thermal stresses
that do much worse damage than ice crystals.

>To achieve this it would probably
>require some sort of microwave like device for cooling things quickly.

How could you manage that? Microwaves heat things by being absorbed by
them. Generally speaking, there is no way to stimulate an object to
spontaneously emit radiation in such a way as to make it cooler than
its immediate surroundings. I haven't thought of it deeply, and there
might be some way that one could manage to get an object to emit
more radiation than it absorbs using some trick, but I don't know of

>  So, how can we avoid ice damage anyway?

By using cryoprotectants.

Sorry to say this, but there are professionals working on these sorts
of problems, and people are being suspended regularly these days, with
okay, but not perfect, cryoprotectants. I suggest you read up on the
state of the art before suggesting something like soap or "microwave
Perry Metzger		
		  Just say "NO!" to death and taxes.
			 Extropian and Proud.

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