LONGECITY

Post any ideas you have of ways to improve cryonics in this thread. Bonus points if your a scientist or graduate student or something.

If you're a laymen, you can get started by watching this:
http://video.google....44955525659858#

also, here are some links to help you come up with ideas:
http://www.scienceda...nanotechnology/
http://www.scienceda...anic_chemistry/
http://www.scienceda...anic_chemistry/

This might be kind of goofy, but I figure why not, this forum should actually accomplish something rather than just discuss things we already know.

think outside the box.

Some of my ideas:

• Slice the brain, and preserve the slices. Tissue slices are much easier to preserve than whole organs because you can add and remove cryoprotectant much more quickly. Temperature can also be reduced more quickly without fracturing, and fractures should be more easy to repair for slices. Repair strategies could include printing, as well as other kinds of nanotech that require high degree of surface exposure.
• Use a large warehouse to store the patients. The higher the volume the less surface area per unit volume, so the less cooling power it consumes per patient. A container of a given shape with twice the diameter will have double the efficiency per unit volume.

I am not specialized in that field at all, but here are 2 ideas:

• work towards full body solutions only. Reason: when one cuts the spinal cord of an animal (rat for example), within 1 or a few seconds the animal is dead. So brain only or even slices only do not look very reasonable in that respect. Plus the hope is that for full body, me may actually not be that far from being able to preverse and come back to life within a few decades.
• allow laymen to contribute in solving the technical issues. try to transpose a current technical limit to something that can be tested at home (eg. freeze red fish) so that people can try at home and develop their own techniques to overcome the issue

Encourage cryonicists to use available technologies like brain cooling helmets and remote health monitoring to increase the quality of preservations.

• Use red blood cells to systematically go through each possible cryoprotectant and find the least toxic solutions.
• Put up a prize for the least toxic vitrification solution every year.
• Put together a wiki documenting everything there is to know about the organic chemistry of cryoprotectants.

Is what Luke Parrish proposes feasible at home?? would it big a big step for cryogenics?

Also bgwowk recently summarized current limits in crogenics: http://www.imminst.o...731#entry434731
From this and the first post of this thread it would be nice to make a clear, simple, concise text of what is needed technically to improve cryonics. The text could be sent to labs working on related fields.

The biggest single basic scientific advance that would benefit the science of cryobiology is better understanding and mitigation of cryoprotectant toxicity.

• Use red blood cells to systematically go through each possible cryoprotectant and find the least toxic solutions.
• Put up a prize for the least toxic vitrification solution every year.
• Put together a wiki documenting everything there is to know about the organic chemistry of cryoprotectants.

Those are great ideas, the cryoprotectant wiki is something ImmInst could do. Also, I love the idea of systematically going through millions of possible chemicals. This is exactly how drug companies do drug development, they start with a target and then generate hundreds of thousands of possibilities, and then use high throughput drug screening machines to test hundreds of thousands of them to see if they work or not.

See these videos:
Drug Development
link
High Throughput Screening
link

There is also virtual screening.
http://en.wikipedia....rtual_screening

Also, why do you need to go so cold? How much preservation would be possible at say -3 degrees C? At this temperature you could use Anti-Freeze Proteins link and link, right? Anti-Freeze Proteins sound very interesting, they require very low concentration to work, and have no toxicity, however,I believe they only work to about -6 C. The sugar glucose is an anti-freeze as well and has no toxcicity, some frogs apparently increase glucose so they don't freeze, I wonder what the effect of eating tons of glucose prior to cryopreservation would be? In fact diabetes, which causes high blood sugar is thought to be more common in people living in cold climates because it is an evolutionary adaptation which increases resistance to cold link.

The sweet thing about Type 1 diabetes: a cryoprotective evolutionary adaptation.
Moalem S, Storey KB, Percy ME, Peros MC, Perl DP.

Department of Pathology, Mount Sinai School of Medicine, Box 1134, New York, NY 10029, USA. sharon.moalem@mssm.edu


Abstract
The reasons for the uneven worldwide distribution of Type 1 diabetes mellitus have yet to be fully explained. Epidemiological studies have shown a higher prevalence of Type 1 diabetes in northern Europe, particularly in Scandinavian countries, and Sardinia. Recent animal research has uncovered the importance of the generation of elevated levels of glucose, glycerol and other sugar derivatives as a physiological means for cold adaptation. High concentrations of these substances depress the freezing point of body fluids and prevent the formation of ice crystals in cells through supercooling, thus acting as a cryoprotectant or antifreeze for vital organs as well as in their muscle tissue. In this paper, we hypothesize that factors predisposing to elevated levels of glucose, glycerol and other sugar derivatives may have been selected for, in part, as adaptive measures in exceedingly cold climates. This cryoprotective adaptation would have protected ancestral northern Europeans from the effects of suddenly increasingly colder climates, such as those believed to have arisen around 14,000 years ago and culminating in the Younger Dryas. When life expectancy was short, factors predisposing to Type 1 diabetes provided a survival advantage. However, deleterious consequences of this condition have become significant only in more modern times, as life expectancy has increased, thus outweighing their protective value. Examples of evolutionary adaptations conferring selection advantages against human pathogens that result in deleterious effects have been previously reported as epidemic pathogenic selection (EPS). Such proposed examples include the cystic fibrosis mutations in the CFTR gene bestowing resistance to Salmonella typhi and hemochromatosis mutations conferring protection against iron-seeking intracellular pathogens. This paper is one of the first accounts of a metabolic disorder providing a selection advantage not against a pathogenic stressor alone, but rather against a climatic change. We thus believe that the concept of EPS should now include environmental factors that may be nonorganismal in nature. In so doing we propose that factors resulting in Type 1 diabetes be considered a result of environmental pathogenic selection (EnPS).

KEEP BRAINSTORMING!
Edited by nanothan, 24 November 2010 - 05:04 AM.

Great videos! I wonder whether it would be more optimal to hire a drug testing company to screen millions of compounds rather than attempt to do it at home. Are there companies that do this? I can see how larger economies of scale could make it less expensive over all, and possibly with better quality control etc.

What's the best way of making sure the cryoprotectant does not end up extremely expensive? If development costs can be kept down, perhaps the knowledge can be released into the public domain quickly and thus manufactured inexpensively in bulk by anyone who needs it. The more affordable it is to produce the sooner the better.

On the other hand, if we do come up with a cryoprotectant that allows reversible preservation of particular organs but not whole patients, it may be smarter to patent it and sell it to organ transplant companies in order to earn money to invest into developing better full-body cryonics.

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.

Anyone who wants a primer on how cryoprotectants work can read the article here

http://www.alcor.org...ryonics0703.pdf

There is a long list of known cryoprotectants in this old Karow paper

http://www.ncbi.nlm..../pubmed/4390139

I've also found the paper on red blood cell permeability and partition coefficients by Naccache and Sha'afi to be a very useful reference

http://www.ncbi.nlm....139/pdf/714.pdf

Generally any molecules with a ether/water partition coefficient of more than a few percent will be too toxic to be a useful cryoprotectant.

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.

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:

Only a small class of drugs—small molecules with high lipid solubility and a low molecular mass (M_r ) of < 400–500 Daltons (Da)—actually cross the BBB .

(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.

This 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)

KEEP BRAINSTORMING!
Edited by nanothan, 24 November 2010 - 11:31 PM.

DMSO + trehalose looks nice.
http://diabetes.diab.../3/519.abstract

Trehalose: a cryoprotectant that enhances recovery and preserves function of human pancreatic islets after long-term storage.
G. M. Beattie, J. H. Crowe, A. D. Lopez, V. Cirulli, C. Ricordi, A. Hayek

The scarcity of available tissue for transplantation in diabetes and the need for multiple donors make it mandatory to use an optimal cryopreservation method that allows maximal recovery and preservation of beta-cell function. We have developed a method to cryopreserve islets with excellent survival of endocrine cells. Current methods use DMSO as cryoprotectant. Our method involves introducing both DMSO and the disaccharide trehalose into the cells during cooling. Uptake and release of trehalose occurred during the thermotropic lipid-phase transition measured in pancreatic endocrine cells between 5 degrees and 9 degrees C, using [14C]trehalose. Recovery of adult islets after cryopreservation with 300 mmol/l trehalose was 92 vs. 58% using DMSO alone. In vitro function, in terms of insulin content and release in response to secretagogues, was indistinguishable from fresh islets. Grafts from islets cryopreserved with trehalose contained 14-fold more insulin than grafts from islets cryopreserved without trehalose. Results with human fetal islet-like cell clusters (ICCs) were more pronounced: recovery from cryopreservation was 94%, compared with 42% without trehalose. Complete functionality of fetal cells was also restored; tritiated thymidine incorporation and insulin content and release were similar to fresh tissue. After transplantation in nude mice, there was a 15-fold increase in insulin content of grafts from ICCs cryopreserved with trehalose compared with ICCs cryopreserved without trehalose. Thus, the addition of trehalose to cryopreservation protocols leads to previously unobtainable survival rates of human pancreatic endocrine tissue.

VERY interesting thing I just found about a revolutionary approach to cryonics using "clathrate hydrates": http://cryostasis.com/cryostasis.php



Edited by nanothan, 25 November 2010 - 12:14 AM.

While certainly different from either vitrification or freezing, it's never been shown to preserve living tissue as far as I'm aware.

I agree, and it seems the only real way to do this would be with computer simulations.

In regards to using computer simulations for research and analysis, I recommend looking into distributed computing to provide the muscle power. See the World Community Grid as a reference point: http://www.worldcomm...d.org/index.jsp

Toxicity has already been studied empirically in cryobiology for 60 years. It's time to learn what's really going on.

The first step to doing that is to find out what is damaged. So has that been discovered, which organelles or proteins are damaged, and in what way they are damaged? Could the damage be caused simply by dehydration?

Responding to a few miscellaneous questions from earlier:

Temperatures warmer than the glass transition temperature (approximately -120 degC) aren't suitable for long-term storage because if cryoprotectants are present the water inside cells will still be in a liquid state. Water/cryoprotectant mixtures become very viscous at low temperatures, but they are still liquid until the glass transition temperature is reached.

I've done molecular molecular modeling of ice blocker adhesion to ice. Some of my work is right here



However I've not yet attempted molecular modeling of toxicity mechanisms.

According to what I have read, the size limit (for penetrating cryoprotectants) is higher:

Only a small class of drugs—small molecules with high lipid solubility and a low molecular mass (M_r ) of < 400–500 Daltons (Da)—actually cross the BBB .

Molecules weighing several hundred Daltons only penetrate cells and the blood-brain barrier (BBB) if they are very lipid soluble. Molecules hydrophobic enough to penetrate cells by virtue of membrane solubility would be toxic if used at high concentrations. Bear in mind that typical studies looking at getting compounds into cells or the brain are in the context of drug development, where only very small quantities are needed for effectiveness. Cryoprotectants need to be present at tens of percent concentation, thousands of times more concentrated than drugs or anesthetics.

Some kind of officialty, regulatory, or accreditation board, commission, or council would probably help public perception/public relations of/pertaining to Cryonics.

Another way to improve Cryonics would be for us (as Cryonicists) to address and deal with the issues of autopsy and 'death with dignity/hope' (aka human-euthanasia). With regards to autopsy, possibly pushing for more and stronger 'objection-to-autopsy' laws, or even pushing for a law exempting Cryonicists specifically from ever having to undergo the procedure (the exception being CT or other uninvasive procedures, and to be done as quickly as possible). A law enabling the right to choose death (thereby skipping the autopsy problem altogether) would also be good for Cryonics.

We might even want to consider changing the terms we use.

These address the 'here and now' issues to improve Cryonics. But ultimately perfecting some kind of reversible suspended animation procedure, or at the very least, perfecting (or very nearly perfecting) a non-toxic anti-freeze solution or procedure that addresses and corrects the major problems involved in the freezing process. Since we are likely about 100-200 years away from being able to revive people who are cryopreserved under current methods/procedures/conditions, i will not even address reanimation technology. That is something left to future generations (most even yet to be born, although some of its infancy has begun).

I'm going to list the best ideas which have come from the brainstorm so far (in the random order that I saw them):


1. Put up a prize for the least toxic vitrification solution every year.
2. Slicing the brain, and preserving the slices
3. Put together a wiki documenting everything there is to know about the organic chemistry of cryoprotectants.
4. Use red blood cells to systematically go through each possible cryoprotectant and find the least toxic solutions
5. DMSO + trehalose link
6. super fast, super precise robotic surgery link
7. Clathrate Hydrates
8. High Throughput Screening for cryoprotectant efficacy and toxicity
9. Molecular modeling to determine the mechanisms of cryoprotectant toxicity link
10. Anti-Freeze Proteins link link2
11. New ways of getting large molecules through the blood-brain barrier link
12. Delivering large molecules through cells with a virus link
13. Using supercomputers to screen and develop new cryoprotectants link
Computational drug discovery:
http://www.youtube.com/watch?v=TTtrk0Ue-Cg&feature=related

The drug discovery process (this video won some awards, so check it out):
http://www.youtube.com/watch?v=d9ouk_46xA8&feature=related

This is pretty good so far, but I don't want to bog people down with what has already been done. Keep brainstorming and try to think of every possible way to overcome the current problems in cyronics.
Edited by nanothan, 30 November 2010 - 11:36 PM.

That list could do with some pruning.

> 2. Slicing the brain, and preserving the slices

For a brain with an intact circulatory system, that's a terrible idea.

> 4. Use red blood cells to systematically go through each possible cryoprotectant and find the least toxic solutions

Red blood cell assays are only useful for screening for gross membrane toxicity. That's not the kind of toxicity that is the limiting factor of present vitrification solutions. Toxicity mechanisms are more subtle than cell lysis.

> 5. DMSO + trehalose link

Trehalose is a non-penetrating cryoprotectant.

> 6. super fast, super precise robotic surgery link

I don't see what that has to do with cryobiology.

> 7. Clathrate Hydrates

This technology may become interesting if and when it is ever shown that it can preserve living tissue.

> 10. Anti-Freeze Proteins link link2

In suggesting AFPs so often, cryonicists may think that AFPs have been ignored in cryobiology. This is not the case. It only seems that way because AFPs have been displaced by synthetic ice blockers that perform similarly at one thousandth the cost. Also, there is a limit to the utility of ice blockers, natural or synthetic, because they are non-penetrating compounds and do not replace the need for colligative cryoprotectants.

> 12. Delivering large molecules through cells with a virus link

I think you mean micelles, not viruses. Even then, once cryobiologically useful quantities of a substance are introduced into cells, it is not clear how they would be removed.

we are left with

1. Put up a prize for the least toxic vitrification solution every year.
3. Put together a wiki documenting everything there is to know about the organic chemistry of cryoprotectants.
7. test if Clathrate Hydrates can preserve tissue
8. High Throughput Screening for cryoprotectant efficacy and toxicity
9. Molecular modeling to determine the mechanisms of cryoprotectant toxicity link
10. Anti-Freeze Proteins link link2 : how to produce them at much lower costs?
11. New ways of getting large molecules through the blood-brain barrier link
13. Using supercomputers to screen and develop new cryoprotectants link


Apart from #7 and #10 all this aims at understanding and mitigating cryoprotectant toxicity. This leads to: what is the state-of-the-art knowledge of cryoprotectant toxicity? What could be a good model of it that one could play with at home, or in a non-cryobiology lab?

That list could do with some pruning.

> 5. DMSO + trehalose link

Trehalose is a non-penetrating cryoprotectant.

That is why I think the best ideas I found were all about how to get larger molecules into the cell. It is already being used in cancer treatments, see here: http://www.epeiusbio...ology-video.asp

> 6. super fast, super precise robotic surgery link

I don't see what that has to do with cryobiology.

The link I gave was for the Da Vinci robotic surgery system just to show that a crude system is already out there, and there is no physical reason why extremely fast and precise computer controlled surgery will not be possible in the future. The purpose of super-fast surgery would be to remove the brain as cleanly and quickly as possible. It sounds crazy, but there is nothing in the laws of physics that says that removing a brain cleanly couldn't be done in 30 seconds.

> 10. Anti-Freeze Proteins link link2

In suggesting AFPs so often, cryonicists may think that AFPs have been ignored in cryobiology. This is not the case. It only seems that way because AFPs have been displaced by synthetic ice blockers that perform similarly at one thousandth the cost. Also, there is a limit to the utility of ice blockers, natural or synthetic, because they are non-penetrating compounds and do not replace the need for colligative cryoprotectants.

Again, I think the issue of non-penetration can be overcome. Since AFPs are a protein, it should even be possible to inject genetic material into the cell which would then manufacture designer AFPs inside the cell, it sounds far off but this is the same concept that Rexin-G is based on. http://www.epeiusbio...ology-video.asp http://molinterv.asp...ent/3/2/90.full

> 12. Delivering large molecules through cells with a virus link

I think you mean micelles, not viruses. Even then, once cryobiologically useful quantities of a substance are introduced into cells, it is not clear how they would be removed.

I wouldn't get hung up on how you are going to remove the substance, if nothing else you could have another nanoparticle virus which injects something to destroy the cryoprotectant.

The key things that I would do if I had a $1 billion would be:
1. Use molecular modeling to try to figure out what causes cryoprotectant toxcity.
2. Once cryoprotectant toxcity is understood, develop a molecule which can prevent cryoprotectant toxcity.
3. Assume that a mechanism for delivering large molecules will be created, and then use computational drug development to find an ideal cryoprotectant, regardless of its size.
4. Try to come up with an ideal combination of traditional cryoprotectants and AFPs, ice blockers and toxcity preventers to use in vivo.

Actually though, all that might not even be necessary if you can deliver large molecules. There seems to be lots of non-penetrating cryoprotectants already known, if you could deliver those cryoprotectants that alone might be enough to preserve large organs.
Edited by nanothan, 02 December 2010 - 12:53 AM.

> 6. super fast, super precise robotic surgery link

I don't see what that has to do with cryobiology.

The link I gave was for the Da Vinci robotic surgery system just to show that a crude system is already out there, and there is no physical reason why extremely fast and precise computer controlled surgery will not be possible in the future. The purpose of super-fast surgery would be to remove the brain as cleanly and quickly as possible. It sounds crazy, but there is nothing in the laws of physics that says that removing a brain cleanly couldn't be done in 30 seconds.

I'm not aware of any form of cryopreservation that needs to have a brain removed from anything. If anything a brain inside a cranium has a pretty good storage container while still providing adequate access to vasculature for perfusion techniques.

Oh, and Da Vinci surgeries are more precise but also much slower than the same operation done the old-fashioned way.

I'm not aware of any form of cryopreservation that needs to have a brain removed from anything.

Agreed. A brain without flotation in cerebrospinal fluid, and protection of the cranium, is not much stronger than Jello. Removing it is likely to cause injury unless it is made rigid by chemical fixation prior to removal. Preservation of isolated brains usually only occurs in cryonics if someone else has removed the brain first, such as a pathologist doing a medico-legal autopsy.
Edited by bgwowk, 03 December 2010 - 08:00 AM.

> 7. Clathrate Hydrates

This technology may become interesting if and when it is ever shown that it can preserve living tissue.

I'm not sure whether they actually tested how much of the tissue was still alive, but at least they have definitely proven increased preservation of the mitochondria in heart tissue.
http://www.ncbi.nlm....75/?tool=pubmed

Cardiac mitochondrial membrane stability after deep hypothermia using a xenon clathrate cryostasis protocol - an electron microscopy study.
Sheleg S, Hixon H, Cohen B, Lowry D, Nedzved M.
Innovative Biological Preservation Technologies LLC Scottsdale, AZ, USA. Sergey.Sheleg@asu.edu

We investigated a new cryopreservation method using xenon, a clathrate-forming gas, under medium pressure (100psi). The objective of the study was to determine whether this cryostasis protocol could protect cardiac mitochondria at cryogenic temperatures (below 100 degrees Celsius). We analyzed transmission electron microscopy images to obtain information about changes in mitochondrial morphology induced by cryopreservation of the hearts. Our data showed absence of mitochondrial swelling, rupture of inner and outer membranes, and leakage of mitochondrial matrix into the cytoplasm after applying this cryostasis protocol. The electron microscopy results provided the first evidence that a cryostasis protocol using xenon as a clathrate-forming gas under pressure may have protective effects on intracellular membranes. This cryostasis technology may find applications in developing new approaches for long-term cryopreservation protocols.

It seems to me that there are adequate technologies in existence right now such as directional freezing, variable magnetic field freezing, flavonoid additives, and clathrate formation etc, for science to develop fully (or damn near fully) reversible whole body cryopreservation within the next 10 years. We should at the very least be way ahead of where we currently are (or claim to be). As far as I understand, the only factor preventing this (or that may prevent this from happening soon) is a lack of vision and just as importantly, a lack of serious funding.

That list could do with some pruning.

> 2. Slicing the brain, and preserving the slices

For a brain with an intact circulatory system, that's a terrible idea.

How confident can we be that a given person's brain has an intact circulatory system when they have died of natural causes? When people die a prolonged agonal death, or from a stroke, it seems likely that their circulatory system is compromised enough that this would have positive value for them.

Also, exactly how terrible of an idea is it even if that is the case, and what are the primary concerns? It may just be my inexperience talking, but I have more trouble visualizing reversal of toxicity than engineering a way around the structural issues caused by slicing. Isn't the experimental evidence stronger for high cell survival rates in slices than in full organs?

> 4. Use red blood cells to systematically go through each possible cryoprotectant and find the least toxic solutions

Red blood cell assays are only useful for screening for gross membrane toxicity. That's not the kind of toxicity that is the limiting factor of present vitrification solutions. Toxicity mechanisms are more subtle than cell lysis.

Thanks for clarifying this. Is there any other kind of low-cost procedure for testing the prevention and mitigation of toxicity mechanisms that would be useful for small scale researchers?

So Brian, what do you think of using something like this: http://www.epeiusbio...ology-video.asp to insert non-penetrating cyroprotectants like trehalose into cells?
What about inserting genetic material to manufacture AFPs inside the cell (of course in addition to regular cryoprotectant)?


Also, how much potential money is in the cryoprotection of organs for transplantation? It seems that if there was a potential for lots of money, all the big pharmaceutical companies and biotech companies would be developing cryoprotectant drugs, but I couldn't really find any except 21st Century Medicine.

Is this because of the regulations in the US about organ transplantation? If someone was to develop a flawless cryonics system for organ transplantation, who would be paying them for it? The government? Insurance companies?

It seems like the government has screwed up again making organ donation so highly regulated they have made it so no biotech companies will try to invest in developing new cryoprotectants, because the gains would be too small.
Edited by nanothan, 04 December 2010 - 04:55 AM.

Programming cells to make AFP is not very useful because they have no time to do that. In a cryopreservation cells are in deep hypothermia, all but shutdown to protect them from the toxicity of cryoprotectants which are introduced as rapidly as possible. Carrying certain non-penetrating cryoprotectants into cells is potentially useful, and has been done in cryobiology by various techniques, but the mileage ones gets is limited because once you get to a vitrifiable concentration of cryoprotectants, I don't know of any non-penetrating cryoprotectants that are dramatically less toxic than penetrating ones.

Programming cells to make AFP is not very useful because they have no time to do that. In a cryopreservation cells are in deep hypothermia, all but shutdown to protect them from the toxicity of cryoprotectants which are introduced as rapidly as possible. Carrying certain non-penetrating cryoprotectants into cells is potentially useful, and has been done in cryobiology by various techniques, but the mileage ones gets is limited because once you get to a vitrifiable concentration of cryoprotectants, I don't know of any non-penetrating cryoprotectants that are dramatically less toxic than penetrating ones.

Maybe something similar like this could be useful.
http://www.ncbi.nlm....pubmed/19528681

The encapsulation and intracellular delivery of trehalose using a thermally responsive nanocapsule.
Zhang W, Rong J, Wang Q, He X.
Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208, USA.

The thermally responsive wall permeability of an empty core-shell structured Pluronic nanocapsule (together with its temperature dependent size and surface charge) was successfully utilized for encapsulation, intracellular delivery, and controlled release of trehalose, a highly hydrophilic small (M(W) = 342 D) molecule (a disaccharide of glucose) that is exceptional for long-term stabilization of biologicals (particularly at ambient temperatures). It was found that trehalose can be physically encapsulated in the nanocapsule using a soaking-freeze-drying-heating procedure. The nanocapsule is capable of physically withholding trehalose with negligible release in hours for cellular uptake at 37 degrees C when its wall permeability is low. A quick release of the encapsulated sugar can be achieved by thermally cycling the nanocapsule between 37 and 22 degrees C (or lower). A significant amount of trehalose (up to 0.3 M) can be delivered into NIH 3T3 fibroblasts by incubating the cells with the trehalose-encapsulated nanocapsules at 37 degrees C for 40 min. Moreover, cytotoxicity of the nanocapsule for the purpose of intracellular delivery of trehalose was found to be negligible. Altogether, the thermally responsive nanocapsule is effective for intracellular delivery of trehalose, which is critical for the long-term stabilization of mammalian cells at ambient temperatures and the eventual success of modern cell-based medicine.

Some more info about how varying the temperature gets the trehalose in the cells.
http://nanotechweb.o...ticle/lab/39621