Cryobiology and Cryonics
Cryobiology is the science that studies the preservation of biological materials by cooling them to cryogenic temperatures. Fear of the inevitable death led many people to sign up for cryonics, the cryopreservation of people after they die in hope they can be brought back to life in the future. Here, I review the history of cryonics, the current state of this 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 Jones had missed an obvious point: instead of hoping aliens will one day repair one's frozen body, human breakthroughs in technology may one day make it possible for physicians to repair the brain and revive someone frozen in the past. Cryonics was born. A couple of hundred patients have already been cryopreserved and when Ettinger died in 2011 he was too.
Cryopreserving humans is already done in cryonics. Briefly, after being pronounced dead, patients are injected with antifreeze compounds called cryoprotectants to prevent ice formation, temperature is slowly lowered and eventually patients are are cryopreserved in liquid nitrogen at very low temperatures (< -130°C), hoping one day they will be revived. Some companies offer patients the option of cryopreserving their whole body or only the head (neuropreservation). With today's technologies, cryonics severely damages the body's cells, which means that it will take huge scientific advances, in areas such as stem cells and nanotechnology, to make these individuals alive and healthy again, as further discussed below.
Cryonics derives from immortalism, venturism and dreams of immortality. Being immortality scientifically impossible by today's knowledge, and death a mundane event with aging an inevitable barrier to one's longevity, many people turn to cryonics in hope it will allow them to wait in a state of suspended animation until they can be brought back to life and rejuvenated in the future. If death is eternal oblivion then cryonics offers an alternative and the prospect, no matter how unlikely, of a future life. Cryonics is particularly popular among transhumanists.
Progress and Limitations
Even assuming that humanity will survive long enough for technology to progress to the point when reviving patients in biostasis is feasible and that present-day cryonics companies will still exist, there are several major problems with cryonics. One issue 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 matter -- during the cryopreservation process is noticeable. Even in controlled laboratory conditions, some cell types can be cryopreserved with high viability but not others. Although cryoprotectants are injected into patients, they don't penetrate all cells and don't completely prevent ice formation. Besides, the cryoprotectants are themselves toxic to cells. So cell viability with current cryonics protocols is likely to be low.
The rewarming process also damages 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 assume technology will be advanced enough to prevent damage during revival. But even only taking into account the damage done during the cryopreservation process, cell death and damage is likely to be substantial. 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 soon after death much damage can occur as neurons begin to die soon after cardiac arrest and this 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 rewarm the body or head, repair it and bring it back to life. One possible answer to the technical difficulties may lie in nanotechnology, particularly to repair the damage in the brain. Even if this is possible, though, there is the potential problem of losing one's identity, because the information lost in the dead neurons and destroyed synapses would likely be impossible to recover. So even if I'm cryopreserved 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. While this of course depends on the severity of the damage to the brain -- and there is hope it will not be as severe -- there is the possibility that a loss of identify may occur even in the best case scenarios. Likewise, proponents of copying the neural information to reproduce one's mind in a computer -- a process also called mind uploading -- are in my view missing the crucial point that a copy of my mind is not me.
There has been progress in the field of cryopreservation. Cryonics now relies on vitrification, which is a process by which intercellular water is replaced by high concentrations of cryoprotectants to minimize 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. Hasan Alam at Massachusetts General Hospital is working on a similar approach to drop the temperature of emergency patients to protect the bodies from damage while undergoing surgery. There are other cases of dogs being frozen for up to one hour and being able to live again. Gregory Fahy and colleagues at 21st Century Medicine vitrified a rabbit kidney and then transplanted it into a live animal with the kidney maintaining some degree of function. Still, there are several technical problems to be solved and no estimation can be made on if/when this technology will work.
Interestingly, there are some species of insects that appear to survive complete freezing during winter. Likewise, some species of frogs can produce their own antifreeze during winter and be partly frozen. Although there have been some attempts to study these animals, it is still very preliminary.
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. If I were diagnosed with some lethal disease that would kill me in a short time I would possibly sign up for cryonics, and I am happy to develop research (albeit thus far small) in my lab on cryopreservation. 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.
CryoNet; cryonics mailing-list (ironically frozen but still informative).