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For the study of the production of very low temperatures, see Cryogenics. For the low-temperature preservation of living tissue and organisms in general, see Cryopreservation. For the Hot Cross album, see Cryonics (album).
Technicians prepare a legally dead patient for cryopreservation.

Cryonics (from Greek κρύος 'kryos-' meaning 'cold') is the low-temperature preservation of animals and humans who cannot be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future.[1]

Cryopreservation of people or large animals is not reversible with current technology. The stated rationale for cryonics is that people who are considered dead by current legal or medical definitions may not necessarily be dead according to the more stringent information-theoretic definition of death.[2] It is proposed that cryopreserved people might someday be recovered by using highly advanced technology.[3]

Some scientific literature supports the feasibility of cryonics.[3][4] An open letter supporting the idea of cryonics has been signed by 63 scientists, including Aubrey de Grey and Marvin Minsky.[5] However, many other scientists regard cryonics with skepticism.[6] As of 2014, the majority of members of the cryonics organizations are men, but the majority of those who have undergone cryopreservation procedures are women.[7]

Cryonics procedures ideally begin within minutes of cardiac arrest, and use cryoprotectants to prevent ice formation during cryopreservation.[8]


A central premise of cryonics is that long-term memory, personality, and identity are stored in durable cell structures and patterns within the brain that do not require continuous brain activity to survive.[9] This premise is generally accepted in medicine; it is known that under certain conditions the brain can stop functioning and still later recover with retention of long-term memory.[10] Brain structures encoding personality and long-term memory persist for some time after legal death, these structures are preserved by cryopreservation, and future technologies that could restore encoded memories to functional expression in a healed person are theoretically possible. At present, only cells, tissues, and some small organs can be reversibly cryopreserved.[11][12]

A moral premise of cryonics is that all terminally ill patients should have the right, if they so choose, to be cryopreserved.[13]

Obstacles to success[edit]

Preservation injury[edit]

Long-term cryopreservation can be achieved by cooling to near 77.15 Kelvin (approximately -196.01°C), the boiling point of liquid nitrogen. It is a common mistaken belief that cells will lyse (burst) due to the formation of ice crystals within the cell, since this only occurs if the freezing rate exceeds the osmotic loss of water to the extracellular space.[14] However, damage from freezing can still be serious; ice may still form between cells, causing mechanical and chemical damage. The difficulties of recovering complex organisms from a frozen state have been long known. Attempts to recover large frozen mammals by simply rewarming were abandoned by 1957.[15]

When used at high concentrations, cryoprotectants stop ice formation completely. Cooling and solidification without crystal formation is called vitrification.[16] The first cryoprotectant solutions able to vitrify at very slow cooling rates while still being compatible with tissue survival were developed in the late 1990s by cryobiologists Gregory Fahy and Brian Wowk for the purpose of banking transplantable organs.[17][18] This has allowed animal brains to be vitrified, warmed back up, and examined for ice damage using light and electron microscopy. No ice crystal damage was found.[19]


Those who believe that revival may someday be possible generally look toward advanced bioengineering, molecular nanotechnology,[20] or nanomedicine[21] as key technologies. Revival would require repairing damage from lack of oxygen, cryoprotectant toxicity, thermal stress (fracturing), freezing in tissues that do not successfully vitrify, and reversing the effects that caused the patient's death. In many cases extensive tissue regeneration would be necessary.

It has sometimes been written that cryonics revival will be a last in, first out process. People cryopreserved in the future, with better technology, may require less advanced technology to be revived because they will have been cryopreserved with better technology that caused less damage to tissue. In this view, preservation methods would get progressively better until eventually they are demonstrably reversible, after which medicine would begin to reach back and revive people cryopreserved by more primitive methods. Revival of people cryopreserved by early cryonics technology may require centuries, if it is possible at all. The "last in, first out" view of cryonics has been criticized because the quality of cryopreservation depends on many factors other than the era in which cryopreservation takes place.[22]

Legal issues[edit]

Legally, cryonics patients are treated as deceased persons.[23][24] Cryonics providers tend to be treated as medical research institutes. In France, cryonics is not considered a legal mode of body disposal;[25] only burial, cremation, and formal donation to science are allowed. However, bodies may legally be shipped to other, less restrictive countries for cryonic freezing.[26]

Ethical considerations[edit]

Cryonics views legal death as a perhaps sometimes pragmatically useful but fundamentally flawed and usually incorrect diagnosis which has no theoretical or philosophical justification. "Legal death" is usually just another name for a set of symptoms that have proven resistant to treatment by contemporary medicine. If death is not an event that happens suddenly when the heart stops (and "legal death" is often pronounced) this raises philosophical questions about what exactly death is. In 2005 an ethics debate in the medical journal, Critical Care, noted “…few if any patients pronounced dead by today’s physicians are in fact truly dead by any scientifically rigorous criteria.”[27] Ethical and theological opinions of cryonics tend to pivot on the issue of whether cryonics is regarded as interment or medicine. Many followers of Nikolai Fyodorovich Fyodorov, a Russian Orthodox Christian philosopher, see cryonics as an important step in the Common Cause project which he originated.[28]

In 1969, a Roman Catholic priest consecrated the cryonics capsule of Ann DeBlasio, one of the first cryonics patients.[29]

At the request of the American Cryonics Society, in 1995, philosopher Charles Tandy, [30] authored a paper entitled “Cryonic-Hibernation in Light of the Bioethical Principles of Beauchamp and Childress.” Tandy considered the four bioethical factors or principles articulated by philosophers Beauchamp and Childress as they apply to cryonics. These four principles are 1) respect for autonomy; 2) nonmaleficence; 3) beneficence; and 4) justice. Tandy concluded that in respect to all four principles “biomedical professionals have a strong (not weak) and actual (not prima facie, but binding) obligation to help insure cryonic-hibernation of the cryonics patient.”[31]


20th century[edit]

In 1922 Alexander Yaroslavsky, member of Russian immortalists-biocosmists movement, wrote "Anabiosys Poem". However, the modern era of cryonics began in 1962 when Michigan college physics teacher Robert Ettinger proposed in a privately published book, The Prospect of Immortality,[32] that freezing people may be a way to reach future medical technology. (The book was republished in 2005 and remains in print.) Even though freezing a person is apparently fatal, Ettinger argued that what appears to be fatal today may be reversible in the future. He applied the same argument to the process of dying itself, saying that the early stages of clinical death may be reversible in the future. Combining these two ideas, he suggested that freezing recently deceased people may be a way to save lives. In 1955 James Lovelock was able to reanimate rats frozen at 0 Celsius using microwave diathermy.[33]

Slightly before Ettinger’s book was complete, Evan Cooper[34] (writing as Nathan Duhring) privately published a book called Immortality: Physically, Scientifically, Now that independently suggested the same idea. Cooper founded the Life Extension Society (LES) in 1964 to promote freezing people. Ettinger came to be credited as the originator of cryonics, perhaps because his book was republished by Doubleday in 1964 on recommendation of Isaac Asimov and Fred Pohl, and received more publicity. Ettinger also stayed with the movement longer.

21st century[edit]

In 2015 Du Hong, a 61-year-old female writer of children's literature, became the first known Chinese person to be cryopreserved.[35]

DARPA currently funds several research projects aimed on sending the human body into a state of suspended animation, essentially “shutting down” the heart and brain until proper care can be administered that can be regarded as a step to cryopreservation of humans.[36]

In popular culture[edit]

Suspended animation in fiction is a popular theme in science fiction and fantasy settings, appearing in literature, comic books, films, and television. A survey in Germany found that about half of the respondents were familiar with cryonics, and about half of those familiar with cryonics had learned of the subject from television or film.[37]

Famous people[edit]

The best known cryopreserved patient is baseball player Ted Williams. The urban legend suggesting Walt Disney was cryopreserved is false; he was cremated and interred at Forest Lawn Memorial Park Cemetery.[38][39] Robert A. Heinlein, who wrote enthusiastically of the concept in The Door into Summer, was cremated and had his ashes distributed over the Pacific Ocean. Timothy Leary was a long-time cryonics advocate, and signed up with a major cryonics provider. He changed his mind, however, shortly before his death, and so was not cryopreserved.

Hal Finney[40] and L. Stephen Coles[41] were cryopreserved in 2014. Among cryopreserved are also James Bedford,[42] Dick Clair,[42] Thomas K. Donaldson,[42] FM-2030,[42] Jerry Leaf,[42] and John-Henry Williams.[42]

See also[edit]


  1. ^ McKie, Robin (13 July 2002). "Cold facts about cryonics". The Observer. Retrieved 1 December 2013. Cryonics, which began in the Fifties, is the freezing - usually in liquid nitrogen - of human beings who have been legally declared dead. The aim of this process is to keep such individuals in a state of refrigerated limbo so that it may become possible in the future to resuscitate them, cure them of the condition that killed them, and then restore them to functioning life in an era when medical science has triumphed over the activities of the Banana Reaper. 
  2. ^ Whetstine L, Streat S, Darwin M, Crippen D (2005). "Pro/con ethics debate: When is dead really dead?". Critical Care 9 (6): 538–42. doi:10.1186/cc3894. PMC 1414041. PMID 16356234. 
  3. ^ a b Merkle RC (September 1992). "The technical feasibility of cryonics". Medical Hypotheses 39 (1): 6–16. doi:10.1016/0306-9877(92)90133-W. PMID 1435395. The extant literature supports but does not prove the hypothesis that cryonics is a feasible method of saving the lives of people who would otherwise certainly die. 
  4. ^ "An open letter to scientific critics of cryonics". Paul Crowley's Blog. Retrieved 2010-02-14. Though many experts in cryogenics and other relevant fields are quoted in the media as condemning cryonics practice, none have written at greater length to explain their reasons. ... this is my plea to the scientific critics of cryonics: Please criticise cryonics. If you thought that someone else had done it, if you thought that the article you’d want a cryonics hopeful to read had already been written, I hope that the surveys above show you that it really hasn’t. 
  5. ^ "Scientists Open Letter on Cryonics". Retrieved 2013-03-19. 
  6. ^ Lovgren, Stefan (18 March 2005). "Corpses Frozen for Future Rebirth by Arizona Company". National Geographic. Retrieved 15 March 2014. Many cryobiologists, however, scoff at the idea... 
  7. ^ Bob Nelson; Kenneth Bly; Sally Magana (18 March 2014). Freezing People Is (Not) Easy: My Adventures in Cryonics. Lyons Press. pp. 237–. ISBN 978-1-4930-0779-0. 
  8. ^ Best BP (April 2008). "Scientific justification of cryonics practice" (PDF). Rejuvenation Research 11 (2): 493–503. doi:10.1089/rej.2008.0661. PMID 18321197. 
  9. ^ Mayford M, Siegelbaum SA, and Kandel ER (April 10, 2012). "Synapses and Memory Storage" (PDF). Cold Spring Harb Perspect Biol. doi:10.1101/cshperspect.a005751. Procedural and declarative memories differ dramatically. They use a different logic (unconscious vs. conscious recall) and they are stored in different areas of the brain. Nevertheless, these two disparate memory processes share several molecular steps and an overall molecular logic. Both are created in at least two stages: one that does not require the synthesis of new proteins and one that does. In both, short-term memory involves covalent modification of preexisting proteins and changes in the strength of preexisting synaptic connections, whereas long-term memory requires the synthesis of new proteins and the growth of new connections. Moreover, both forms of memory use PKA, mitogen-activated protein kinase (MAPK), CREB-1, and CREB-2 signaling pathways to convert short-term to long-term memory. Finally, both forms appear to use morphological changes at synapses to stabilize long-term memory 
  10. ^ Guyton, Arthur C. (1986). "The Cerebral Cortex and Intellectual Functions of the Brain". Textbook of Medical Physiology (7th ed.). W. B. Saunders Company. p. 658. ISBN 0-7216-1260-1. We know that secondary memory does not depend on continued activity of the nervous system, because the brain can be totally inactivated by cooling, by general anesthesia, by hypoxia, by ischemia, or by any method, and yet secondary memories that have been previously stored are still retained when the brain becomes active once again. Therefore, secondary memory must result from some actual alterations of the synapses, either physical or chemical. 
  11. ^ Fahy GM, Wowk B, Wu J (2006). "Cryopreservation of complex systems: the missing link in the regenerative medicine supply chain". Rejuvenation Research 9 (2): 279–91. doi:10.1089/rej.2006.9.279. PMID 16706656. 
  12. ^ Fahy GM, Wowk B, Pagotan R; et al. (July 2009). "Physical and biological aspects of renal vitrification". Organogenesis 5 (3): 167–75. doi:10.4161/org.5.3.9974. PMC 2781097. PMID 20046680. 
  13. ^ The Ad Hoc Committee on Medical Ethics, American College of Physicians (July 1984). "American College of Physicians Ethics Manual. Part II: Research, Other Ethical Issues. Recommended Reading". Annals of Internal Medicine 101 (2): 263–267. doi:10.7326/0003-4819-101-2-263. Each patient is a free agent entitled to full explanation and full decision-making authority with regard to his medical care. John Stuart Mill expressed it as: `Over himself, his own body and mind, the individual is sovereign.' The legal counterpart of patient autonomy is self-determination. Both principles deny legitimacy to paternalism by stating unequivocally that, in the last analysis, the patient determines what is right for him. ... If the [terminally ill] patient is a mentally competent adult, he has the legal right to accept or refuse any form of treatment, and his wishes must be recognized and honored by his physician. 
  14. ^ Mazur P (September 1984). "Freezing of living cells: mechanisms and implications". The American Journal of Physiology 247 (3 Pt 1): C125–42. PMID 6383068. 
  15. ^ Smith Audrey U (1957). "Problems in the Resuscitation of Mammals from Body Temperatures Below 0 degrees C". Proceedings of the Royal Society of London. Series B, Biological Sciences 147 (929): 533–44. doi:10.1098/rspb.1957.0077. JSTOR 83173. 
  16. ^ Fahy GM, MacFarlane DR, Angell CA, Meryman HT (August 1984). "Vitrification as an approach to cryopreservation". Cryobiology 21 (4): 407–26. doi:10.1016/0011-2240(84)90079-8. PMID 6467964. 
  17. ^ Fahy GM, Wowk B, Wu J; et al. (April 2004). "Cryopreservation of organs by vitrification: perspectives and recent advances". Cryobiology 48 (2): 157–78. doi:10.1016/j.cryobiol.2004.02.002. PMID 15094092. 
  18. ^ Fahy, G; Wowk, B; Wu, J; Phan, J; Rasch, C; Chang, A; Zendejas, E (2005). "Corrigendum to "Cryopreservation of organs by vitrification: perspectives and recent advances" [Cryobiology 48 (2004) 157–178]". Cryobiology 50 (3): 344. doi:10.1016/j.cryobiol.2005.03.002. 
  19. ^ Lemler J, Harris SB, Platt C, Huffman TM (June 2004). "The arrest of biological time as a bridge to engineered negligible senescence". Annals of the New York Academy of Sciences 1019 (1): 559–63. doi:10.1196/annals.1297.104. PMID 15247086. 
  20. ^ Nanofactory Collaboration
  21. ^ Robert A. Freitas Jr., Nanomedicine, Landes Bioscience; Vol I (1999), Vol IIA (2003)
  22. ^ de Wolf, Aschwin (2009-01-20). "5 dangerous idea about cryonics". Depressed Metabolism. Retrieved 2010-03-07. 
  23. ^ Legal Protection of Cryonics Patients, Part 1, INSTITUTE FOR EVIDENCE BASED CRYONICS
  24. ^ Legal Protection of Cryonics Patients, Part 2, INSTITUTE FOR EVIDENCE BASED CRYONICS
  25. ^
  26. ^ Chrisafis, Angelique (16 March 2006). "Freezer failure ends couple's hopes of life after death". The Guardian. Retrieved 8 January 2014. 
  27. ^ Whetstine, Leslie; Stephen Streat; Mike Darwin; David Crippen (2005-10-31). Pro/con ethics debate: When is dead really dead?. Critical Care Forum. Retrieved 2006-03-17. 
  28. ^ Fedorov seminar in Moscow, Russia on 25.11.2006
  29. ^ Curtis Henderson (September–October 1969). "Cryonic Suspension of Ann DeBlasio". Cryonics Reports (Cryonics Society of New York, Inc.) 4 (9–10): 10–15. 
  30. ^ Tandy, Charles. "Charles Tandy, Ph.D.". Retrieved 2008-10-10. 
  31. ^ Charles Tandy (1995). "Cryonic-hibernation in light of the bioethical principles of Beauchamp and Childress". Retrieved 2008-04-01. 
  32. ^ Ettinger, Robert C.W. (1964). The Prospect of Immortality (First ed.). Doubleday. ISBN 0-9743472-3-X. 
  33. ^ Andjus, R.K.; Lovelock, J.E (June 28, 1955). "Reanimation of rats from body temperatures between 0 and 1C by microwave diathermy". The Journal of Physiology 128 (3): 541–546. PMC 1365902. PMID 13243347. 
  34. ^ "Ev Cooper". Retrieved 2006-03-17. 
  35. ^ Stephen Chen. "Cheating death? Elderly writer is the first known Chinese to embrace cryogenics, her head now frozen by lab in Arizona | South China Morning Post". Retrieved 2015-09-24. 
  36. ^ Put, Should We. "h+ Magazine | Covering technological, scientific, and cultural trends that are changing human beings in fundamental ways". Retrieved 2012-11-18. 
  37. ^ Kaiser S1, Gross D1, Lohmeier J1, Rosentreter M1, Raschke J2 (2014). "Attitudes and acceptance toward the technology of cryonics in Germany". INTERNATIONAL JOURNAL OF TECHNOLOGY ASSESSMENT IN HEALTH CARE 5 (1): 1–7. doi:10.1017/S0266462313000718. PMID 24499638. 
  38. ^ "Urban Legends Reference Pages: Disney (Suspended Animation)". 
  39. ^ "The Truth About Walt Disney and Cryogenics". 
  40. ^ "Bitcoin's Earliest Adopter Is Cryonically Freezing His Body to See the Future - WIRED". WIRED. 
  41. ^ Los Angeles Times (4 December 2014). "L. Stephen Coles dies at 73; studied extreme aging in humans". 
  42. ^ a b c d e f "The Quick 8: Eight People Who Have Been Cryonically Preserved (and one who wasn't)". Mental Floss. 2009-02-11. Retrieved 2015-09-13. 

External links[edit]