Cryobiology and Cryonics
Cryobiology is the science that studies the preservation of biological materials by cooling them to cryogenic temperatures. So promising and appealing cryopreservation is that many people sign up to be frozen after they die in hope they can be brought back to life in the future. Here, I review the current state of the technology and its flaws.
Origins of Cryonics
Cryonics was first proposed by Robert Ettinger, inspired by Neil R. Jones's science fiction story, "The Jameson Satellite." "The Jameson Satellite" tells how Professor Jameson has his body sent into orbit where it remains frozen for millions of years until, with humankind extinct, aliens repair his brain and bring him back to life. Ettinger recognized that Neil R. Jones had missed an obvious point: instead of hoping aliens will one day repair one's frozen body it makes a lot more sense to hope that breakthroughs in technology will one day make it possible for physicians to repair the brain and revive someone frozen in the past. Cryonics was born.
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Cryopreservating humans is already done in cryonics. Humans who are legally dead (although there were a few cases where persons could have been frozen alive) are frozen in liquid nitrogen at very low temperatures (< -130°C), hoping one day they might be young and living again. Companies generally offer patients the option of freezing their whole body or only the head. With today's technologies, cryonics severely damages the body's cells, which means that it will take huge steps for science, such as nanotechnology, to make these patients living and healthy again, as further discussed below. |
Cryonics derives from immortalism and venturism and dreams of immortality. Being immortality scientifically impossible by today's knowledge, and death a mundane event, many patients turn to this technology in hope it will allow them to wait in a state of suspended animation until they can be brought back to life and live, theoretically speaking, forever. Cryonics is particularly popular among transhumanists.
Progress and Limitations
The major flaw of cryopreservation is that we might lose our individuality in the process. During freezing, ice crystals form inside cells that can destroy them; the damage done to the cells -- including to neurons, which are what really matters -- during the freezing process is noticeable. In the laboratory, the rate of survival of cells during freezing can be quite low. To my knowledge, only blood and sperm cells can be frozen for long periods of time without major loss of function. Even organs can only be frozen for a limited amount of time. This problem is not easy to fix. Although a cryoprotectant or antifreeze like glycerol is injected into the patient prior to freezing, it doesn't penetrate all cells and doesn't completely prevent ice formation.
Interestingly, there are some species of frogs that can produce their own antifreeze during winter. Although there have been some attempts to research these animals, they are never completely frozen so whether they will be useful to improve the freezing procedure remains to be seen.
It appears that the thawing process also damages the cells because as ice crystals thaw and combine this creates tensions that can destroy the cells. In the future, patients hope this won't be a problem because they presume technology will be advanced enough to prevent it. But even only taking into account the damage done during freezing, many cells will die or be damaged. In addition, many patients die in old age when they have already suffered much molecular and cellular damage to their bodies. Crucially, if patients are not frozen immediately after death, much damage can occur and hinder any hope of future revival.
In the future, which can be dozens, hundreds or thousands of years from now, it will be necessary to thaw the body or head, repair it and bring it back to life. The answer to all the technical difficulties may lie in nanotechnology, particularly to repair the damage in the brain cells. Even if this is possible, though, there is the potential problem of losing one's identity, because the information lost in the dead and destroyed neurons would likely be impossible to recover. So even if I'm frozen and then it becomes possible to reconstruct my brain and put new neurons in it, depending on the extent of the damage, I will no longer be me! I will be a different person because my brain will be much changed. My new me might have some memories of how I used to be, but I will no longer exist. Even if it is possible to calculate all of the previous positions and connections of the dead neurons and put new neurons ones back into my brain, this person will be exactly like me but not me, as I debate in another essay.
There has been progress in the area. Cryonics now relies on vitrification, which minimizes molecular and cellular damage. A team lead by Hal Sternberg of Biotime claimed to bring back to life baboons that were previously cooled to one degree Celsius. They injected a substance called Hextend to replace the blood and protect the cells from deterioration. They aim to proceed with tests using liquid nitrogen. There are other cases of dogs being frozen for up to one hour and being able to live again. Still, there are several technical problems to be solved and no estimation can be made on when this technology will work.
Personally, I prefer to study aging and genetics, even though I must admit that cryopreservation can play an important role in the future, not only in medicine but also in space exploration. In addition, presently it's the only hope to achieve physical immortality; paraphrasing James Halperin: "Would you rather be part of the experimental group, or the control group?"
Sources and Links
Ettinger, Robert; "The Prospect of Immortality: The Scientific Probability of the Revival and Rejuvenation of Our Frozen Bodies" (1962). A classic book, available online.
Halperin, James L; "The First Immortal" (1998). Check out the site about the book. This sci-fi novel is much more than a story, it's a scientific and deeply researched perspective of the future.
Alcor Life Extension Foundation
CryoCare; cryonics services.
CryoNet; cryonics mailing-list.
Prometheus Project; is a future research project on cryopreservation.