What is death? Over the centuries, the line dividing life and death has moved from the cessation first of breathing, then of the heartbeat, and finally of brain activity. But cryogenic methods first contemplated in science fiction may push the line even further. The idea is to freeze legally dead people in liquid nitrogen in the hope of regenerating them at some future date. Today’s cryonics scientists believe that this future may be a mere 100 years away. Alcor Life Extension Foundation, in Scottsdale, Ariz., the world’s largest cryonics company, charges US $150 000 to freeze and maintain a body and $80 000 for a head, typically paid for with a life insurance policy.
Ralph Merkle, a nanotechnology expert and a director at Alcor, believes the best approach lies in developing nanorobots that can repair the body at the cellular level before thawing. They would fix or replace diseased and deteriorated tissue as well as the tissue fractures and denatured proteins that result from the freezing process itself. The revival process would, ideally, restore the physiology of dead persons to a pristine level, not only undoing the damage of whatever disease or accident killed them but also enabling them to return smarter and healthier than they ever were in life.
”We’re talking about a fundamentally more powerful medical technology than we have today that will continue the evolution of the concepts of life and death,” says Merkle, who holds bachelor’s and master’s degrees in computer science from the University of California, Berkeley, and a Ph.D. in electrical engineering from Stanford. ”People will be able to suffer more damage and still fully recover.”
Before the body is cooled to –196 °C (the temperature at which liquid nitrogen becomes a gas), the person’s blood is replaced by a cryoprotective solution that doesn’t freeze at those temperatures. Technically, the body and cryoprotective solution are not frozen but vitrified—that is, they solidify into a glassy substance that’s free of ice crystals and the damage they can cause. The first step in the future regeneration process would remove this vitrified liquid, letting physicians use the circulatory system as a series of tunnels through which they could run nanomedical robots, nanomaterials, and a removable high-speed fiber-optic network connecting to an external supercomputer.