In this blog post, we’ll explore the principles, procedures, limitations, and significance of the cryonics project.
The Concept and Purpose of the Cryonics Project
From Qin Shi Huang of China’s Qin Dynasty to the pharaohs of ancient Egypt, what do these historical figures have in common? They possessed wealth, fame, and even the supreme power of mighty nations, yet there was one thing they ultimately failed to attain: the ability to live forever. From the great kings of antiquity to modern-day college students, no one can escape death. That is why people have long yearned to overcome death. Even if they cannot live forever, everyone wants to avoid losing their life to an incurable disease or a serious injury. One of the technologies currently being researched based on this universal human aspiration is the cryonics project.
The cryonics project is a concept that aims to cryopreserve people suffering from incurable diseases or conditions—which cannot be treated with current technology—until future medical technology has advanced sufficiently, and then thaw them when a cure becomes available. However, as of now, the technology to cryopreserve a human and then revive them has not been realized, and no actual cases of successful revival have been reported. This article examines the principles and methods of cryopreservation, as well as its limitations and significance.
Principles of Cryopreservation and Cryopreservation Procedures
The basic principle of cryopreservation technology is to lower the body’s temperature to preserve it in a state where cellular damage is minimized. Cryopreservation generally proceeds through three main steps.
The first is the stabilization process. This refers to the procedure of maintaining blood circulation to slow cellular damage as much as possible immediately after a doctor determines that the patient has no chance of resuscitation. One of the criteria doctors generally use to declare a person dead is the cessation of cardiac function. This is because damage to the body’s cells begins the moment they are deprived of oxygen, and the heart plays a role in circulating blood to supply oxygen to cells throughout the body. Therefore, during the stabilization phase, blood circulation is maintained using a CPS (Cardiopulmonary Support) device to preserve the cells as much as possible. Unlike CPR (Cardiopulmonary Resuscitation), the purpose of CPS is not to revive the person but to maintain blood circulation; thus, various pieces of equipment are used in conjunction. While administering various drugs to protect the cells, the body temperature is lowered and chest compressions are performed.
The second procedure involves the administration of cryoprotectants. When any substance is at a high temperature, various chemical reactions occur. Therefore, to preserve human cells for an extended period, the temperature must be lowered to extremely low levels. However, simply freezing the body will destroy the cells. We’ve likely all experienced how frozen fruit at the supermarket is cheaper than fresh fruit, yet its taste and texture are inferior to that of fresh fruit. This is because ice crystals formed as the water inside the fruit freezes destroy the cells. The human body is no different. If blood is frozen as is, ice crystals form, compressing and damaging the cells.
To understand this, we must understand the properties of water. Water is a classic example of a substance whose volume increases when it changes from a liquid to a solid. Water molecules form hydrogen bonds with neighboring molecules to create a regular hexagonal crystal structure; because this structure contains many empty spaces, the volume increases. Therefore, before freezing, blood must be replaced with another solution that does not freeze—this solution is known as an antifreeze agent. Antifreeze agents undergo vitrification rather than forming ice crystals even as the temperature drops. Vitrification refers to the phenomenon in which, as the temperature drops, viscosity increases instead of crystals forming, eventually transforming into a glass-like, amorphous solid state. During this process, the body’s fluids are replaced with the cryoprotectant over approximately 12 hours to protect the cells.
The third step is the freezing process. During this process, the body is gradually cooled using nitrogen, which is cooled to approximately -124°C.
Since the vitrification temperature of the cryoprotectant is approximately -124°C, the entire body must be cooled below this temperature within a certain time frame to prevent crystal formation. Afterward, the body is cooled to approximately -196°C using liquid nitrogen, at which point it enters a state of long-term cryopreservation.
Limitations and Significance of Cryopreservation Technology
We have examined the cryopreservation procedure above. From a purely procedural standpoint, cryopreservation technology is theoretically very well-structured. This is because it is conceivable that, should cures for diseases be developed in the future, a cryopreserved body could be thawed in the reverse order to receive treatment. However, in reality, there are many limitations that need to be addressed.
First, even the slightest damage occurring during the thawing process can have fatal consequences for the human body. In particular, brain cells find it difficult to recover normal function even if only a tiny fraction is damaged. Furthermore, as of now, there is no technology to revive a cryopreserved person, nor has a method been developed to fully repair the cellular damage caused during the freezing and thawing processes. Additionally, cryopreservation is currently limited to individuals who have been legally declared dead. Since the cryopreservation procedure begins only after a doctor has determined that resuscitation is no longer possible, there is a limitation in that, no matter how quickly it is carried out, cellular damage has already begun by the time the process starts.
Finally, despite these clear limitations, let us examine why cryopreservation technology continues to be researched and what its significance is. First, cryopreservation technology can offer hope to patients with incurable diseases. There is a story that when Pandora opened her box, all manner of disasters spread throughout the world, but the one thing that remained until the very end was hope. This is sometimes interpreted to mean that as long as hope remains, even in the face of any disaster, one can maintain the will to live. Even in situations where everyone deems survival impossible, cryopreservation technology can serve as a source of hope that allows us to anticipate future possibilities.
Furthermore, cryopreservation technology holds significance from the perspective of being a long-term treatment strategy rather than merely a post-mortem measure. Alcor, a U.S.-based cryopreservation organization, states on its website, “To say that someone is dead simply means that current medicine has no way to treat that person.” From this perspective, cryopreservation technology is being researched as a long-term treatment strategy that looks toward the potential advancements of future medicine, even at the very moment when everyone else has given up on treatment. However, this potential has not yet been proven, and there remain numerous scientific and medical challenges that must be addressed in the future.
