On January 12, 1967, James Bedford died. But- he had a plan to cheat death. Bedford was the first person to be cryogenically frozen. The process promised to preserve his body until a theoretical future when humanity could cure any disease, and essentially, reverse death.
This is the dream of cryonics. But here's the catch: in order to resurrect people in the future, we need to properly preserve them in the present. So, is it currently possible to freeze a human, preserve them indefinitely, and then safely thaw them?
To understand the constraints of human cryopreservation, we need to leave the theoretical realm of cryonics and turn to the scientific field of cryobiology.
This discipline studies the effects of low temperatures on various living systems, and it is true that a decrease in the temperature of an organism also decreases its cellular function. For example, at temperatures below -130 degrees Celsius, human cellular activity stops.
So if you could bring the whole human body down to that temperature,
You could theoretically preserve it indefinitely.
The hard part is doing this without damaging the body. For example, let's try freezing a single red blood cell.
It usually sits at 37 degrees Celsius in a solution of water and substances called chemical solutions, which dissolve under certain conditions. But once the temperature drops below freezing, the water outside and inside the cell hardens, damaging the ice crystals.
Without the correct concentration of water,
chemical solutions cannot dissolve. And as water freezes, they become increasingly concentrated in a destructive process known as osmotic shock. Without intervention, these factors destroy our red blood cells before they reach -130 degrees.
Not all cells are so delicate, and many animals have evolved to survive in extreme conditions. Some cold-tolerant fish synthesize antifreeze proteins to prevent ice formation at sub-zero temperatures. And freeze-tolerant frogs use protective agents to survive when 70% of their body water is trapped as ice.
It is unlikely that any single creature holds the secret to human cryopreservation. But by researching these adaptations, scientists have developed remarkable conservation technologies, some of which are already at work in medicine.
However, researchers are still trying to improve cryopreservation technology to better manage the ice problem. Many cryobiologists are trying to solve this problem with an approach called vitrification.
This technique uses chemicals known as cryoprotectant agents (CPA) to prevent ice from forming. Some of these are adapted from nature's compounds, while others are designed to take advantage of the guiding principles of cryobiology.
But in practice,
these chemicals allow researchers to store living systems in a glassy state with little molecular activity and no harmful ice. Vitrification is ideal for cryonics, and will help preserve organs and other tissues for medical procedures.
But this is incredibly difficult to achieve. CPAs can be toxic at high concentrations required for large-scale vitrification. And even with these chemicals, rapid cooling is required to prevent ice formation that lowers the temperature evenly throughout the material.
This is relatively easy when vitrifying single cells or small pieces of tissue. But as the material becomes more complex and contains larger amounts of water, it becomes harder to stay ahead of ice formation.
And even if we could successfully vitrify complex living material,
we would only be halfway to using it. Vitrified tissues also need to be heated evenly to prevent ice formation, or worse, cracks.
To date, researchers have been able to vitreate and partially restore small structures such as blood vessels, heart valves, and the cornea. But none of them come close to the size and complexity of a whole human.
So if it's not possible to save a person right now, what does that mean for Bedford and his frozen companions? The sad truth is that current cryonics preservation techniques only offer false hope to their patients.
As practiced, they are both unscientific and deeply destructive,
causing irreparable damage to the body's cells, tissues and organs. Some devotees may argue that this loss, like death and disease, may one day return.
Even if scientists can bring people back to life through cryonics preservation, there are a whole host of ethical, legal, and social implications that cast doubt on the overall benefits of the technology. But for now, the cryonics dream is still on ice.
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