The Science of Cryonics
On November 5th, 2005, an Open Letter endorsing the scientific legitimacy of cryonics as a subject for serious study and research was signed on by no less than sixty scientists, physicians, and cryobiologists from institutions as prestigious as NASA, Cambridge, Oxford, and Columbia and Georgetown Universities.
The letter was one more step forward for the emerging science of cryonics, a research field with immense medical and social implications and vast potential benefits. But a field that has had to wage a hard struggle against media sensationalism and public misunderstanding.
Yet the technology of cryonics and cryomedicine is advancing, and is doing so ever more rapidly every day.
The Feasibility of Cryonics
Spaceflight was shown to be theoretically possible long before it ever actually occurred. Cryonics has gotten similar support from top individuals in the scientific community. Yet the hope that advanced future technology may be able to help people with current health problems is regarded by some as showing that cryonics owes more to hope than to science.
But emerging technologies and clearly developing technological breakthroughs are foreseeable in many fields.
The key question for cryonics is whether advanced but plausibly predicted technologies can in theory restore organs and tissues preserved by current technology. The answer according to a growing number of scientists is yes.
What Sciences Support cryonics?
Cryonics is not the belief that people can be 'frozen' by any crude means and be assured of near-term revival by miracle technologies. Its scientific plausibility rests on the evidence that damage caused by existing cryopreservation methods can be limited to levels that may one day be repairable. The science that speaks most directly to this issue, is neural cryobiology.
Can a brain be preserved well enough to retain memory and personality? Arguably it can. It is a well-established fact that long-term memories are encoded in enduring physical and chemical changes. Loss of brain activity is clearly survivable in many instances, and sometimes is even deliberately used by surgeons to prevent ischemic injury. Animals that have survived partial freezing show that brain activity can stop and later resume, though such cases have not yet involved cooling much below 0ºC. Yet even whole brains have been shown to recover normal electrical activity activity after freezing to -20ºC for five days with glycerol cryoprotection.
Cryogenic tissue banking methods demonstrate the viability of organic and even human tissue under controlled conditions at ultra-low temperatures. And advances in organ preservation have reached such a point that Israeli scientists were able to announce on September 20, 2005 the successful transplantation of previously frozen ovaries in a group of sheep.
A major breakthrough in contempory cryopreservation methods occurred with the development of vitrification.
The paper, "Vitrification as an Approach to Cryopreservation" (Cryobiology 21, 407-426 (1984)) ushered in a new era in cryopreservation, by describing a new means of cooling tissue without ice crystal formation or ice damage. Embryos, ova, skin, pancreatic islets, blood cells, blood vessels, and other tissues have since all been successfully vitrified. Whole kidneys have been reversibly cooled to -50°C (-58°F) with full recovery when protected by vitrification solutions. Vitrification is now widely regarded as the most promising new approach for the long-term storage of large organs.
K. Eric Drexler
If vitrification has been shown to successfully preserve and restore sheep kidneys, can it do the same for other organs? For the human brain? Though progress continues, the results of vitrification when applied to the brain remain controversial.
Yet there is no doubt that progress in this area has advanced doctors' capacity to better preserve the structure and much of the biochemistry of the brain. A return to undamaged normal metabolic functioning by cryopreserved brains has not as yet been demonstrated, and some believe that eventual repair or replacement of actual molecules altered by freezing or vitrification processes will be mandatory for eventual revival.
Molecular nanotechnology is an emerging technology for manufacturing and manipulating matter at the atomic level. The concept was first suggested by Richard Feynman in 1959, and brought to fruition by Dr. K. Eric Drexler, Dr. Ralph Merkle, and others in the 1980s and 1990s. The coming medical applications of nanotechnology were explored in detail in Robert Freitas' Nanomedicine Vol. I (Basic Capabilities) and Nanomedicine Vol. IIA (Biocompatibility).
The leading figures in the science of nanotechnology have not only concluded that restoration of organ and tissue damage stemming from cryonics is possible, but have become public advocates of cryonics.
As we begin to approach the mid 21st century, extraordinary capabilities for analyzing and repairing injured cells and tissues will surely become more available, they claim. These capabilities will almost surely include improved means for repairing and regenerating tissue that may have suffered injury stemming from cryopreservation.
A non-technical overview of how far those limits may be pushed back by nanotechnology, and an discussion of the high likelihood that nanotechnology may be able to restore patients properly cryopreserved even today, is available for free in the chapter on cryonics, or biostasis, in Eric Drexler's book, Engines of Creation.
Cryonics Society: Selected Cryonics Science Links:
The Science of CryobiologyCryobiology - A Short Course (Online Textbook)
Cryobiology: The Study of Life and Death at Low Temperatures
Institute for Problems of Cryobiology & Cryomedicine
Society for Cryobiology
21st Century Medicine, Inc.
Further Cryobiology and Cryomedicine Links
International Network for Brain Death Research
Safar Center for Resuscitation Research
Suspended Animation - Surgery's Frontier
Nanotechnology and NanomedicineCenter for Responsible Nanotechnology
Institute for Molecular Manufacturing
Ralph Merkle's Cryonics Page
Robert Freitas' Nanomedicine Page
Zyvex Corporation Nanotechnology Introduction Page
The Struggle Against AgingAmerican Aging Assocation
General Science InformationNew Scientist
Science - The Journal
CryonicsAlcor -- cryonics services provider.
Cryonics Institute -- cryonics services provider.
Ben Best's Cryonics FAQ
Ben Best's Cryonics Page
Definition of Death on sci.med -- Steven B. Harris, MD
Scientists' Open Letter on Cryonics
Wikipedia Encyclopedia entry on cryonics
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