Cryonics: Preserving Human Bodies at Ultra-Low Temperatures for Future Revival

Cryonics is the practice of preserving a human body (or sometimes just the brain) at ultra-low temperatures after legal death, with the hope that future technology will allow for revival and restoration to life. Below is a detailed explanation of how cryonics is done, including the science and processes involved:

The Cryonics Process 

1. Legal Death Pronouncement
   Cryonics can only begin after a person is declared legally dead (when the heart has stopped beating). This is because cryonics companies must operate within the law and avoid accusations of premature euthanasia.
2. Stabilization
   • Goal: Minimize damage to the body due to lack of oxygen.
   • After legal death, the body is immediately cooled with ice packs, and circulation is artificially maintained using a heart-lung resuscitator (if accessible) to keep oxygen flowing to the brain.
   • Anticoagulants and other medications are administered to prevent blood clotting and reduce cellular damage.
3. Cooling
   • Goal: Lower the body temperature to slow down metabolic processes.
   • The body is packed in ice and transported to a cryonics facility as quickly as possible.
4. Vitrification (Replacing Body Fluids)
   • Cryoprotectants, a type of antifreeze solution, are introduced into the body to replace water in the cells.
   • This process prevents the formation of ice crystals, which can cause mechanical damage to cells. Instead of freezing, the body tissues vitrify, forming a glass-like solid state.
5. Gradual Cooling to Cryogenic Temperatures
   • The body is cooled to approximately -196°C (-321°F), the temperature of liquid nitrogen.
   • Cooling is done gradually to reduce thermal stress, typically over a period of days.
6. Storage
   • The vitrified body is placed in a specialized storage tank filled with liquid nitrogen.
   • The tank (often a "cryostat") is designed to keep the body at cryogenic temperatures indefinitely, requiring minimal energy since liquid nitrogen does not need refrigeration, only replenishment.

Key Considerations in Cryonics

1. Brain Preservation
   • The focus of cryonics is often on the brain, as it houses memories, personality, and consciousness.
   • If the brain is preserved without damage, proponents hope that future technology could repair any harm and reanimate the body or upload consciousness into a digital form.
2. Legal and Ethical Challenges
   • Cryonics cannot begin until after legal death, which introduces delays that may cause cellular damage.
   • Ethical concerns revolve around consent, costs, and the implications of bringing someone back to life in the distant future.
3. Revival Challenges
   • Current medical science does not have the technology to reverse cryopreservation or repair cellular damage caused by freezing or underlying diseases.
   • Revival would likely require advancements in fields like nanotechnology, genetic engineering, and tissue regeneration.

The Science Behind Cryonics

1. Cryoprotectants
   • These chemicals (e.g., ethylene glycol or DMSO) are vital to prevent ice formation. They replace water in cells to avoid expansion and rupture during freezing.
2. Vitrification vs. Freezing
   • Freezing leads to ice crystal formation, damaging cellular structures.
   • Vitrification transforms cellular liquids into a solid state without crystal formation, preserving tissue structure.
3. Nanotechnology and Repair Hypothesis
   • Future advancements in nanotechnology might allow for microscopic robots to repair cellular and molecular damage caused by disease or the cryopreservation process.

Cryonics Organizations
Several organizations around the world provide cryonics services. Some of the most notable include:

• Alcor Life Extension Foundation (USA)
• Cryonics Institute (USA)
• KrioRus (Russia)

These organizations typically require clients to sign up for their services while alive and prepay for the preservation process. Costs range from $28,000 to over $200,000, depending on whether the full body or just the brain is preserved.

Future Prospects
Cryonics relies on several assumptions:

1. Future science will have the capability to repair molecular damage and reverse aging or disease.
2. Societies of the future will have the resources and motivation to revive cryonically preserved individuals.

Cryonics is still speculative, as no human has been successfully revived after cryopreservation. However, it represents a fascinating intersection of technology, ethics, and the desire to extend life.