The book I’m currently reading is “Preserving Minds, Saving Lives” edited by “Alcor Life Extension Foundation“:

Alcor book

In this article, I’m sharing with you my reading notes.
This is the fifth article about the book. The other articles about it can be read here.

The Preservation Cycle of Cryonics

You thought that it was enough to have yourself immersed in ice to ensure your conservation for eternity? Wrong! If this were the case, we would just dig a hole in the floe and leave you there for a few decades or centuries! This organic solution would be economical and so simple to set up. The people of the future would then only have to find your location and revive you with their super technologies!

The cryopreservation process is currently much more complex than that. I must admit that it poses more challenges than I had imagined.
The book, as always weighted, exposes all the issues of the cryopreservation cycle. The mystery is lifted; those who read this article will have an idea of this process and of the rational on which it is established.


The complete cryonics cycle is based on three sub-cycles

  1. The transport cycle
    This is the cycle that starts in the best case before the imminent death of the patient, until his arrival at the chosen cryopreservation facility. This is a critical cycle that should start as soon as possible after the patient’s legal death. Any delay will increase the damage suffered by an organism no longer benefiting from blood circulation. Thus, successful cryopreservation will depend on the promptness and effectiveness of the events following the clinical death of the patient.
  2. The Preservation cycle
    It is the purpose of this article; the cycle during which the patient will be put in a state of biostasis, frozen or vitrified, “comfortably” installed for decades or centuries to come, waiting to be revived in the best of all worlds!
  3. The resuscitation cycle
    … also called reanimation cycle. This is the most speculative cycle, which will take place in the future, when technologies are sufficiently advanced to allow it. This cycle will be the subject of another article.


The Three Phases of the Cryonics Preservation Cycle

  1. The Blood Washout Phase
    During this phase, the patient is “washed” from all his blood. The reason for this is that the blood coagulates and will prevent the injection of antifreeze agents from the next phase. An infusion is therefore performed with a basic solution to remove the maximum amount of blood from the entire circulatory system. For this purpose, cryopreservation companies use closed-circuit machines to inject the washing solutions through the femoral arteries.
  2. The Antifreeze Agent Injection Phase
    As explained a little further down, it is CRITICAL to minimize the formation of ice crystals that can damage the tissues during the freezing or vitrification phase. This is the reason why an antifreeze is sent throughout the circulatory system to soak the organs.
  3. The Freezing Or Vitrification Phase
    This phase is emblematic of cryonics; phase during which the temperature around the patient is strongly lowered in order to guard against the damage of time.


The Two Methods of Cryopreservation: Freezing and Vitrification

  1. Freezing
    Most of us have in our kitchens a freezer used to preserve our food. Since I learned about cryonics, I do not see my freezer in the same way! Like many of you, I thought that the process of cryonics was simply about lowering the temperature around a body to preserve it. I have probably been badly influenced by my frozen broccoli and the “freezing does not affect the nutritional value of food” I read from my internet researches. Is this principle also valid for the human body? I will not venture to taste, but one thing is certain… If freezing does not affect the nutritional value… it has a dramatic effect on the tissues’ structure!

    The pioneers of cryonics also practiced basic freezing by plunging their deceased patients into liquid nitrogen capable of reaching a temperature of -196 degrees Celsius (colder than in your freezer where it painfully reaches -18 degrees). The absolute zero, the lowest temperature that can exist, is -273.15 degrees Celsius. A low temperature has the virtue of preventing microorganisms proliferation, but also that of slowing down the molecular vibrations. Two powerful factors involved in tissue breakdown.

    The Damages of Freezing

    Our body is 70 percent water. Life is organized water. This water infuses all our cells.
    The problem, big problem of freezing, is that below 0 degrees, this water turns into solid ice crystals that damage living tissues.
    Firstly, because these crystals form pockets of ice within the tissues and they leave “holes” when they are thawed.
    Secondly, and worse, because it is the water in our cells that freezes and not the rest of the constituents. Ice crystals expel all the organic elements they bathed in the liquid state and form outside of their original situs within the cell, thus completely disrupting tissue composition.

    If this freezing does not change the taste of your broccoli and remains a viable way to preserve food… it is totally unfit to preserve a human and the organic structure of his being, personality, and memories. Goodbye freezing then, even if its damage can be mitigated by antifreeze injected into the body.

  2. Vitrification to the rescue
    Vitrification is the transformation of a liquid into a solid by lowering the temperature … WITHOUT the formation of ice crystals!
    This solution for cryopreservation was proposed by Dr. Gregory Fahy in the 1980s, but did not become established until two decades later.
    It involves infusing the body with a specific antifreeze solution and lowering the temperature fast enough to reach the vitrification phase without ice crystals having time to form.

    At around -120 degrees the water/antifreeze mixture will become more and more viscous until it solidifies into glass. Unlike the process of ice crystal formation, the vitrification of water does not occur outside cells; tissue structure is thus better preserved by vitrification than it is by freezing. Vitrification immobilizes molecules and limits chemical changes.
    Tissues vitrified and maintained at low temperature are thus able to withstand the ravages of time much more effectively than freezing allows.

    If you were given to see a vitrified organ, you would note the preservation of its colors, in a sort of compact translucent glass, a little like an insect trapped in amber. A frozen organ would be surrounded by a more or less opaque ice, and would have a white appearance, because of the billions of crystals formed from the water from all its cells. A frozen organ seems to be suffering; a vitrified organ seems to be at rest.Is vitrification a perfect solution? Far from it. The process has its disadvantages.

    Toxic Effects of Antifreeze solutions

    The purpose of the antifreeze solutions is to avoid the formation of ice crystals at low temperatures. Their role is crucial when we know that we are composed of 70% water. They are composed of true chemical antifreeze, such as glycerol, propylene glycol, and dimethylsulfoxide (DMSO).
    In the process of cell cryoprotection, the goal is to replace part of the water with these antifreeze mixtures, in order to achieve a state of vitrification without adjunct freezing.

    We can guess that replacing water cells with antifreeze is not without effect. There is purely mechanical stress from the pressure exerted by the injection of the antifreeze solution, and also a stress on the constituents of the cell, disturbed by the replacement of water by the antifreeze.
    Antifreeze solutions have evolved, but they remain the major problem of cryopreservation. If we could cryopreserve individuals without ice crystals as is the case through vitrification, and without the toxicity of the antifreeze, then we would have reached a significant step of the cryopreservation phase.

    Cracks and fracturing

    Yet another problem induced by the cooling process… that of fractures.

    Imagine a sphere filled with water. If you cool it quickly by plunging it into liquid nitrogen, for example … you literally risk hearing a loud “crack” that will indicate that the content of your sphere has fractured!

    This phenomenon is due to the temperature variations between the different zones of the sphere’s content: the outer part, closer to the walls will cool faster than the sphere’s center, which will create tensions, because an identical element does not occupy the same volume depending on its temperature: it will tend to contract as its temperature drops. So the strongest contraction will happen near the outside of your sphere, which will create a tension with the warmest sphere center. This will produce this audible crack indicating the formation of a fracture.

    You have unfortunately guessed it … this phenomenon also affects human bodies subjected to the radical cooling process, even in the case of vitrification.

    To mitigate this effect, cryonicist will avoid cooling the body beyond what is strictly necessary. No more drop in temperature to -196 degrees Celsius as allowed by liquid nitrogen. Cryonicists will play an equilibrium game, lowering the temperature so that the vitrification process can occur, but not beyond! This intermediate temperature zone is established around -120 degrees Celsius. Lowering the temperature more gradually allows a better homogenization of the body heat drop.
    This intermediate temperature zone makes it possible to reduce fractures, but not to avoid them completely.
    Specific storage tanks are used to precisely control the maintenance of the intermediate temperature zone.

    As of today, and as long as there are fractures, cryonics must project its hopes into a futuristic reparation process that would ensure the viability of the reanimation cycle.

To end this article on a little lighter note, know that reading this book allowed me to solve a little personal problem, which has nothing to do with a cooling process, but on the contrary have everything with warming consequences. It could serve you too!

I need a lot of protein for the sport I practice which is bodybuilding (at medium intensity …). An excellent source of protein is egg white. I break some eggs in a bowl while taking care to keep only the whites. I used to put this appetizing mixture in the microwave at 600 watts for a period of two minutes. In most cases during these two minutes, a kind of audible explosion occurs systematically, and when it does I know that I will have to spend five minutes cleaning my microwave whose walls are covered with exploded egg whites. This explosion is my own “cracking” phenomenon, and thanks to reading the book I was able to deduce the cause: the sudden increase in the mixture’s temperature creates divergent zones of tension and the brutal expansion of air bubbles… which would cause these “explosions”.

So I lowered the warming power of the microwave to 180 watts (instead of 600) and increased the heating duration to six minutes … which probably results in a more homogeneous temperature increase of my egg whites. Result? No more explosion!

The preservation phase is the most technical text of the book thus far. The book gives a lot more details on antifreeze, storage at intermediate temperature, and you should definitely dive into it if you want to know more. What emerges from this part of the book is that cryonics has strongly evolved since its inception, that it has perfected itself, and that the cryonics bet is more than ever closer to succeed thanks to vitrification.

As usual, the book does not overlook the difficulties of current cryonics concerning the preservation phase: antifreeze toxicity and fractures are unresolved problems. It will be interesting, when the book tackles the resuscitation phase, to see what prospects are envisaged in the future to mitigate these current problems with the “repair” process preceding resuscitation.

Update: As the book is a compilation of articles published on different dates, the chapters are not necessarily chronological. In 2006, Alcor managed to cryopreserve without fracture a neuropatient (brain only) at a temperature of -134 degrees.


It is CRITICAL to minimize the formation of ice crystals that can damage the tissues during the freezing or vitrification phase. Click To Tweet If freezing does not change the taste of your broccoli and remains a viable way to preserve food... it is totally unfit to preserve a human and the organic structure of his being, personality, and memories. Click To Tweet If we could cryopreserve individuals without ice crystals and without the toxicity of antifreeze, then we would have reached a significant step of the cryopreservation phase. Click To Tweet As of today, and as long as there are fractures, cryonics must project its hopes into a futuristic reparation process that would ensure the viability of the reanimation cycle. Click To Tweet

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