Could you live forever?

On January 12th, 1967, a man named James Bedford passed away with a unique plan to evade death. Bedford became the first person to undergo cryogenic freezing, a process that aimed to preserve his body until a future time when medical advancements could conquer all diseases and reverse death itself. Cryonics, as it is known, holds the promise of a dream where humans can be revived in the future. However, the key challenge lies in the present: can we currently freeze a human, preserve them indefinitely, and safely revive them later?

To comprehend the obstacles of human cryopreservation, we must step out of the realm of cryonics and delve into the scientific field of cryobiology. Cryobiology focuses on studying the effects of low temperatures on various living systems. It is true that reducing an organism's temperature also reduces its cellular activity. For instance, at temperatures below -130 degrees Celsius, human cellular function comes to a standstill. In theory, if an entire human body could be brought below this temperature, it could be preserved indefinitely. However, the challenge lies in accomplishing this without causing damage to the body.

Let's take the example of freezing a single red blood cell. Normally, a red blood cell exists at a temperature of 37 degrees Celsius in a solution of water and chemical solutes that dissolve under specific conditions. When the temperature drops below freezing, the water inside and outside the cell solidifies into ice crystals, which can be damaging. Additionally, without the right concentration of water, the chemical solutes are unable to dissolve properly. Consequently, as the water freezes, the solutes become increasingly concentrated, leading to a destructive process called osmotic shock. Without any intervention, these factors will inevitably destroy the red blood cell before it reaches -130 degrees.

However, not all cells are as fragile, and many animals have evolved mechanisms to survive extreme conditions. Certain cold-tolerant fish produce antifreeze proteins to prevent ice formation at sub-zero temperatures. Freeze-tolerant frogs employ protective agents to survive even when a significant portion of their body water is trapped as ice. While it is unlikely that any single creature holds the secret to human cryopreservation, scientists have studied these adaptations to develop remarkable preservation technologies, some of which are already used in medicine.

Nevertheless, researchers are continuously working on improving cryopreservation techniques to address the ice problem. One approach being pursued by cryobiologists is vitrification. This technique involves using cryoprotectant agents (CPAs), which are chemicals that prevent ice formation. Some of these agents are derived from natural compounds, while others are specifically designed based on cryobiology's principles. In practice, these chemicals enable researchers to store living systems in a glassy state with reduced molecular activity and no harmful ice formation. Vitrification holds great potential for cryonics and could aid in preserving organs and tissues for medical procedures. However, achieving successful vitrification is incredibly challenging.

One major obstacle is the toxicity of CPAs when used in the high quantities necessary for large-scale vitrification. Additionally, preventing ice formation requires rapid and uniform cooling throughout the material. This is relatively manageable when vitrifying single cells or small tissue samples. However, as the complexity of the material increases and larger quantities of water are involved, it becomes increasingly difficult to prevent ice formation effectively. Even if complex living material could be successfully vitrified, another significant challenge arises—uniformly warming the vitrified tissue to prevent ice formation or the formation of cracks.

To date, researchers have managed to vitrify and partially recover small structures such as blood vessels, heart valves, and corneas. However, none of these structures come close to the size and complexity of a whole human body. Consequently, if cryopreserving an entire person is not currently possible, what does this mean for James Bedford and others who have undergone cryogenic freezing? Sadly, current cryonic preservation techniques only offer false hope to their patients. In practice, these techniques lack scientific rigor and irreparably damage the cells, tissues, and organs of the body.

Some proponents may argue that the damage inflicted during cryonic preservation could be reversible in the future, just like death and disease. Even if scientists were able to revive individuals through cryopreservation, a myriad of ethical, legal, and social implications would cast doubts on the overall benefits of the technology. For now, the dream of cryonics remains frozen, awaiting breakthroughs that may one day bring it to life.