Cryopreservation
Cryopreservation is the process of deep-freezing living cells, organs, or deceased bodies to prevent decay, with the hope of future revival through advanced medical technology. The practice is most commonly associated with the term "cryonics," which specifically refers to the preservation of human bodies after death. Initially discovered in the late 1930s, the technology for freezing human sperm evolved significantly over the decades and led to its use in assisted reproductive technologies like in vitro fertilization (IVF). Pioneered by Robert Ettinger in the 1960s, the concept of cryonics gained public attention, leading to the establishment of organizations that offer cryopreservation services for deceased individuals.
The process involves legal declaration of death, immediate cooling of the body, and careful administration of antifreeze chemicals to prevent ice crystal formation, followed by deep freezing in liquid nitrogen. As of the early twenty-first century, several facilities, primarily in the United States and Russia, provide these services, although critics argue that the revival of cryopreserved bodies remains a speculative concept. They raise concerns about potential cellular damage during freezing and the feasibility of future resuscitation. Despite skepticism, some advocate for the exploration of cryonics, hoping that advancements in science may one day overcome current limitations.
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Cryopreservation
Cryopreservation is the process of deep-freezing living cells, organs, or bodies of deceased people to prevent them from decaying so they can be restored to life after an extended period. The term cryonics refers specifically to the freezing of human bodies for this purpose.
Cryopreserved sperm and embryos are used to impregnate women who struggle to conceive. These materials are frozen until they are ready to be used. Embryos that have been created outside the body from eggs and sperm are later implanted in a woman's uterus in the process of in vitro fertilization (IVF).
Cryogenically freezing deceased human bodies with the ultimate intention of reviving them is a developing science in the early twenty-first century. Supporters believe the deep freeze can preserve bodies long enough for future medical technology to be able to resuscitate them. Critics dismiss cryonics as science fiction, saying the technological breakthroughs necessary to revive cryopreserved bodies will be unattainable for the near future.
Background
Scientists first discovered in the late 1930s and early 1940s that human sperm could survive deep-freezing. In the late 1940s and early 1950s, American and British scientists began using a jelly-like substance called glycerol to protect sperm from damage while frozen. In 1953, researchers in Iowa announced that the first fetus created using frozen sperm would soon be born. The technology used in the cryopreservation of sperm and embryos advanced considerably over the decades, and the first sperm banks began to appear in the United States in the 1970s.
Breakthroughs in freezing sperm for IVF inspired American physics teacher Robert Ettinger to develop his idea of cryonics in the early 1960s. Ettinger was a physics teacher at a Michigan community college in 1962, when he wrote the book The Prospect of Immortality. Ettinger claimed it was indeed possible for deceased people to be specially frozen and then resuscitated in the distant future. He described the "freezer era," when people could live forever by occasionally freezing their bodies for long periods. Ettinger's cryopreservation idea was an immediate sensation among the American public. Mainstream newspapers reported on the concept, and Ettinger himself became a celebrity.
Ettinger's ideas led American scientists to found several organizations that would freeze recently deceased people for a price. The first person ever to be cryogenically frozen was University of California professor James Bedford in 1967. The Cryonics Society of California froze his body soon after his death.
In the 1970s, Ettinger founded the Cryonics Institute, a nonprofit organization that tried to make cryopreservation available to many people through reduced rates. The institute saw some success over the next three decades. By the time of Ettinger's death in 2011, the Cryonics Institute was storing more than one hundred cryogenically frozen human bodies and dozens of pet animal bodies. As of the early twenty-first century, bodies can be cryogenically frozen at three locations in the world. Two of these, the Cryonic Institute and Alcor Life Extension Foundation, are in the United States. The third facility, KrioRus, is in Russia. Fees for cryogenic freezing at the American companies begin at about $28,000.
Overview
Cryopreserving bodies is a complex process that involves more than simply placing bodies in freezing temperatures. To be cryogenically frozen at all, a person must first be declared legally dead. Living people may not legally be cryogenically frozen. While living, people must arrange for a cryonics organization to take possession of their bodies after they die.
The first step in human cryopreservation is to place the bodies of recently deceased people in ice baths or keep them in dry ice until they can be transported to cryonics facilities to be given ice baths. This is a time-sensitive stage of the cryopreservation process, for the initial freezing helps to prevent the bodies from starting to decay. However, the reduction of the body's temperature must be gradual, or the body could be damaged. Cryonics professionals using the ice-bath method at an actual cryonics facility also give the body a ventilation mask at this time. The mask delivers oxygen to the body's brain and other organs to keep them from decaying.
Simultaneously, machines administer cardiopulmonary resuscitation (CPR) to the body, while the scientists inject the body with anticoagulant drugs. CPR manually keeps the heart pumping blood through the body, while anticoagulants thin the blood to make this easier. These processes ensure blood continues to flow through the body. Blood flow is necessary to carry oxygen and other nutrients to all parts of the body.
The next phase of cryopreservation involves injecting the body with antifreeze chemicals. The chemicals replace the body's water, which, during actual cryopreservation, would freeze into ice crystals and destroy cells. The scientists then begin the last stage of cryopreservation: the deep freezing. Bodies are first placed in insulated bags and then into airtight boxes. Scientists gradually inject liquid nitrogen into the box. This chemical is extremely cold and can keep the bodies frozen over long periods. The bodies' temperatures must be lowered slowly, for sudden freezing can damage organs. The bodies reach about -328 degrees Fahrenheit (-200 degrees Celsius) after a few days.
Finally, bodies are placed in large vats of liquid nitrogen called cryostats. The cryostats are sealed and can theoretically be left to sit for decades, centuries, or longer. Cryopreservation scientists hope that, in the distant future, people will have developed the medical technology necessary to warm and revive these bodies, thus artificially extending the lives of the frozen people.
Critics of cryopreservation say the concept is akin to science fiction in the early twenty-first century. They claim that while smaller biological material such as sperm and embryos can be cryopreserved, the extreme cold of the freezing disrupts proteins in body cells and neurons in the brain. These critics also claim cryopreservation makes human bodies so brittle that they are likely to shatter during the eventual warming process. Skeptics also assert that even if frozen people could be revived in the future, many of them would still be aged and infirm, as they were at the point of their deaths. This would complicate the prospect of living again for an extended period.
Nonetheless, cryopreservation critics argue that the freezing process could prove useful if future scientists discover ways to reverse the potentially harmful effects of cryopreservation on the human body. This would make successful revivals possible. As of the early twenty-first century, scientists do not possess the technology to revive cryopreserved bodies.
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