Futurama's Cryogenic Freezing vs. Real World

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Futurama's Cryogenic Freezing vs. Real World

Cryosleep for astronauts

Sep 17, 2024

In the colorful and zany world of Futurama, cryogenic freezing is portrayed as a common technology that's about as complicated as taking a nap in a high-tech tube. If you haven’t seen it, the show introduces us to Philip J. Fry, a hapless pizza delivery boy who stumbles into a cryogenic chamber on New Year's Eve 1999 and wakes up a thousand years later, perfectly preserved.

The cryogenic process, according to the show, is straightforward. Characters simply step into sleek, cylindrical pods, and with a whoosh and a puff of frosty air, they're frozen solid. There's no fuss, no muss, and (thankfully) no complex scientific explanations about cellular preservation or the intricacies of reviving a long-frozen human body.

Throughout the series, cryogenic freezing is used as a convenient plot device, enabling fish-out-of-water scenarios and time-spanning storylines.

And cryogenics is not restricted to Futurama. It features in many science fiction books and movies. How about Alien (1979 - onwards) where the crew of the spaceship Nostromo is placed in hypersleep. How about Passengers (2016) where Chris Pratt and Jennifer Lawrence are traveling on a spaceship in cryosleep. Or Demolition Man (1993) where crime is virtually eradicated by deep freezing prisoners.

Even the ace detective himself, Sherlock Holmes, gets in on the act in The Return of Sherlock Holmes (1987), when he is brought back to life after being cryogenically frozen for eighty years.

I had a dig into the feasibility of cryogenic freezing for space travel, and this is what I found.

What is Cryogenics?

Cryogenics is the broad study and application of extremely low temperatures, typically below -153°C (-243°F). When applied to biological systems, including the human body, the process is more accurately termed 'Cryopreservation'. The aim is to preserve living tissues, organs, or entire organisms by cooling them to very low temperatures, effectively pausing biological processes. Cryogenics encompasses a broad range of applications, including the preservation of organs, organic tissue, entire bodies, and even metals and propellants.

Cryogenic Preservation vs Cryogenic Sleep

Cryopreservation and Cryosleep represent two distinct concepts, each with unique technologies and feasibility challenges.

Cryopreservation is a well-established technique used primarily in biomedicine to preserve biological materials, such as cells, tissues, and organs, at very low temperatures. The process typically involves cooling the biological samples to below -130°C, using methods like slow freezing or vitrification.

Vitrification involves cooling a sample rapidly enough to prevent the formation of ice crystals, which can cause cellular damage. Instead, the sample solidifies into a glass-like state, preserving the molecular structure indefinitely. This process has been successfully used to cryopreserve small biological samples like sperm and embryos.

The technology behind cryopreservation has advanced significantly, but scaling up the process for larger tissues or organs remains a major challenge.

Cryogenic Sleep

In contrast, cryosleep, or induced hibernation, is a theoretical concept to put humans into a state of suspended animation for extended periods, primarily for space travel. By significantly reducing the astronaut's metabolic rate and body temperature, cryogenic sleep could allow them to survive for decades or even centuries in space without aging or consuming resources (food, water, oxygen).

To initiate cryosleep, the body must be cooled to extremely low temperatures, typically below -130°C. This drastic reduction in temperature is crucial because it slows down the body's metabolic processes, effectively putting them on hold. The cooling process can be achieved in various ways, including advanced cooling technologies that might use cryogenic fluids or specialized chambers designed to lower body temperature rapidly and uniformly.

As the body temperature decreases, the metabolic rate drops significantly. For every degree Celsius the core temperature is lowered, metabolic activity can decrease by approximately 5-7%. This reduction in metabolism is essential because it minimizes the energy requirements of the body, meaning it will conserve resources during prolonged periods of inactivity. The aim is to maintain vital functions at a minimal level, ensuring that essential organs, such as the heart and brain, continue to operate, albeit at a much slower pace.

One of the critical components of inducing cryosleep is the use of cryoprotectants - substances that prevent ice crystals from forming within cells. Ice crystal formation can cause severe cellular damage, so these cryoprotectants act like antifreeze, protecting tissues and organs from freezing injuries. Administering these substances is a delicate process, as they can be toxic at certain concentrations, and finding the right balance is crucial for the safety of the individual undergoing cryosleep.

During the cryosleep process, the body still requires a minimal supply of oxygen to sustain vital functions. This is typically managed through mechanical ventilation or other methods that ensure the brain and other critical organs receive the necessary oxygen, albeit in reduced amounts. Waste products must also be managed, often through catheters or other medical interventions, to prevent buildup that could harm the body during the extended period of dormancy.

The revival process from cryosleep is another critical aspect that poses significant challenges. Safely warming the body back to normal temperatures without causing damage from ice formation or other complications is a complicated task that requires precise control and advanced technology. The goal is to restore normal physiological functions and ensure that the individual emerges from cryosleep without lasting harm, physical or cognitive.

Current Research

Current research into cryosleep is advancing through several projects that explore the practical applications of cryopreservation techniques. Here are three of the most advanced research initiatives in this field that I could find:

1. University of California, San Diego (UCSD) - Cryobiology Research

Researchers at UCSD are focusing on the fundamental mechanisms of cryopreservation and how they can be applied to larger biological systems, including mammals. Their work involves optimizing cooling rates and developing novel cryoprotectants to minimize cellular damage during the freezing and thawing processes. They are also investigating the biological responses to low temperatures and how metabolic suppression can be achieved safely.

2. Dayong Gao's Group - Electromagnetic-Assisted Rewarming

The research team led by Dr. Dayong Gao is developing advanced techniques for rapid and uniform rewarming of cryopreserved biological samples. They are using electromagnetic-assisted volumetric heating, which allows for controlled and efficient warming of tissues to avoid damage from ice recrystallization. This approach is particularly promising for the revival process as it addresses the challenge of ensuring that cells and tissues are not harmed during the transition back to normal temperatures.

3. European Biostasis Foundation - Biostasis Research

The European Biostasis Foundation is exploring the concept of biostasis, which involves inducing a state similar to cryosleep in humans. Their research focuses on understanding the effects of low temperatures on human physiology and the potential for metabolic suppression. They are investigating various cryoprotectants and their effects on cellular integrity during the freezing process.

Timeline for Feasibility

Estimating when cryosleep technology might become a reality is tough due to the sheer complexity of the systems involved and the numerous technological hurdles. Experts in the field suggest that significant breakthroughs could occur within the next 10 to 20 years. This timeline is based on the current pace of research and the convergence of various technologies related to cryopreservation, metabolic suppression, and rewarming techniques. As researchers continue to refine these methods and overcome existing challenges, perhaps with the assistance of more powerful AI technology, the possibility of human cryosleep may accelerate in the coming years.

Takeaways

TLDR? Here are the key takeaways:

Cryogenic Freezing in Pop Culture: Cryogenic freezing is often depicted as a simple and convenient plot device in shows like Futurama and movies like Alien, Passengers, and Demolition Man. These portrayals are far removed from the complex science involved.
Cryogenics and Cryopreservation: In reality, cryogenics is the study of extremely low temperatures, while cryopreservation focuses on preserving biological tissues and organs at very low temperatures. Cryopreservation is an established technique in biomedicine, but scaling it for larger systems like whole organs or bodies remains challenging.
Cryogenic Sleep (Cryosleep): Cryosleep is a theoretical concept aimed at putting humans in suspended animation, primarily for long-duration space travel. It involves reducing body temperature and metabolic rate to preserve the body over extended periods. This idea faces significant scientific and technological hurdles, such as preventing ice crystal formation and safely reviving the body.
Current Research: Several advanced research projects are underway:
- UCSD is studying cryopreservation techniques and metabolic suppression in larger biological systems.
- Dayong Gao's team is developing electromagnetic-assisted rewarming methods to minimize damage during revival.
- The European Biostasis Foundation is investigating the effects of low temperatures on human physiology and potential cryosleep applications.
Feasibility Timeline: While cryosleep technology is still a distant reality, experts estimate that breakthroughs could occur within the next 10 to 20 years, driven by ongoing research and advancements in cryopreservation, metabolic suppression, and rewarming technologies.

Note on Cryoprotectants

Cryoprotectants are essential chemicals used to prevent damage to biological tissues during freezing. The most common cryoprotectants include:

Dimethyl Sulfoxide (DMSO)
Glycerol
Ethylene Glycol (EG)
Propylene Glycol (PG)
2-Methyl-2,4-pentanediol (MPD)

These agents work by replacing water in cells, thereby reducing ice formation and minimizing cellular damage during the freezing process. While effective, these cryoprotectants can be toxic to humans, especially at high concentrations.

Toxicity Mechanisms

Cell Membrane Disruption: Many cryoprotectants, particularly those with lipophilic properties, can integrate into cell membranes, destabilizing them. This can lead to cell lysis or apoptosis when the concentration is too high.
Hydrogen Bonding: Cryoprotectants can disrupt the hydration shells around macromolecules, such as proteins and DNA. This disruption can impair the function of these biomolecules, leading to cellular dysfunction.
Metabolic Effects: Some cryoprotectants, like ethylene glycol, are metabolized into toxic compounds in the body. Ethylene glycol, for instance, is converted into glycolic acid and oxalic acid, which can cause metabolic acidosis and damage to the kidneys.
Osmotic Stress: The introduction of high concentrations of cryoprotectants can create osmotic imbalances, leading to cellular dehydration or swelling, which can be harmful.
Concentration-Dependent Toxicity: The toxicity of cryoprotectants generally increases with their concentration. This poses a challenge in cryopreservation, as researchers must balance the need for sufficient cryoprotection with the potential for toxicity.