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What is the significance of low temperatures in cryonics?
There’s a common misconception associated with cryonics, and that is that patients are ‘frozen’. This notion most likely stems from TV and cinema, with sci-fi movies depicting individuals being frozen and ‘thawed’ back to life. This, however, couldn’t be further from the truth, as ice formation is the number one enemy for any cryonicist (!)
Water takes up a greater volume as a solid than it does a liquid. At sub-zero temperatures, liquids expand into ice crystals and puncture and potentially rupture cells. While future medicine will probably be able to reconstruct body tissues using advanced technologies, damage to the brain could be beyond repair, which is why ‘crude freezing’ is not the technique we aim for at Tomorrow Bio, the fastest-growing human cryopreservation provider. However, as cryonics companies do use low temperatures, it’s understandable why people would have doubts, so let’s take a closer look.
There have been cases in the past where people have fallen into very cold waters but have survived, even when they were rescued long after being submerged. Although seemingly impossible, there is a scientific reason behind this. The icy waters lower the body’s temperature, slowing metabolism to the point where oxygen is only needed at a much-reduced rate. This places a body into a type of ‘suspended animation’ and is a similar concept used in cryonics (albeit, in much more complexity). At extremely low temperatures, cell decay ceases and the body enters a ‘biological pause.’ Once an individual enters this state, they can theoretically be stored indefinitely, allowing technology to advance to a point that it can treat the cause of death.
After a patient is declared legally dead, the cryopreservation procedure can begin. First, the patient’s core temperature is brought down by using a mixture of water and ice. After this initiation, perfusion starts, where water within the body is replaced with cryoprotective agents (CPAs), a type of medical-grade antifreeze, to protect cells from hazards like ice crystal formation. At around -125°C, the individual reaches the so-called “glass transition temperature” and achieves vitrification in the process.
Through the cooling and cryopreservation process, metabolic rates are reduced, essentially stopping biological activity, just like the person submerged in the frozen lake. Once the patient is completely perfused, they are moved to the long-term storage facility where they are placed inside a cooling chamber for about a week. After this time, they are then moved into a cryogenic storage dewar once their body reaches -196°C. Here, the patient’s body is stored until revival is possible in the future.
Nitrogen is an odorless, colorless, and tasteless gas with a boiling point of -196°C and a freezing point of -210°C. In its liquid form, nitrogen has multiple uses, like serving as a coolant for computers, removing unwanted skin, warts, and pre-cancerous cells on the body, and, of course, in cryogenics. In human cryopreservation, this chemical element is used in special containers called cryogenic storage dewars.
There are several reasons why cryonics companies (including Tomorrow Bio) use liquid nitrogen for long-term storage. Firstly, it’s relatively cheap in comparison to other gasses, like liquid neon. Because it can be extracted from ambient air makes it environmentally friendly too—an important aspect with regard to long-term storage. Lastly, liquid nitrogen possesses a natural temperature below the glass-transition point, which is where degradation stops and long-term storage can be maintained.
Cryogenic storage dewars are vacuum flask-like containers used for transporting and storing cryogens (liquid nitrogen). The containers were named after British chemist and physicist Sir James Dewar who invented the ‘vacuum flask’ in 1892, known as ‘dewar flask’ or ‘thermos.’ The concept of the cryogenic dewar has similar properties to that of a thermos, which is to minimize heat transfer between inside and outside the container.
The design of the dewar was intended to maintain the temperature of the liquid and the biological material being stored without the use of electricity. The container comprises two or more outside layers of evacuated air in between the layers to create a vacuum gap. On the top, there is a tight stopper cap and a reflective metal layer around the outer layer. The composition of the three elements - a vacuum gap, a tight cap, and a reflective layer work together to prevent heat transfer from occurring.
Dewars come in all shapes and sizes and can hold cryopreserved cells and tissues, semen, and embryos, along with cryopreserved patients.
Tomorrow Bio’s patients are stored at the European Biostasis Foundation’s (EBF) long-term care facility, in Rafz, Switzerland. Cryopreserved patients are stored underground, in one of the safest areas in the world with minimal risks of flooding, crime, and earthquakes for the duration of the storage.
Cryogenic storage dewars can store up to four whole bodies for human cryopreservation. Cryonics providers like Tomorrow Bio generally use dewars made out of stainless steel as it can withstand a long time without deteriorating. The dewars are stored in long-term storage facilities and commonly measure 3+ meters high and 1 meter wide.
Whole-body cryogenic storage dewars are filled to the top with liquid nitrogen so that a patient’s body is completely submerged. At the top of the dewars, liquid nitrogen boils off as it evaporates into a gas. To deal with this, EBF’s storage facility is supplied with liquid nitrogen on a regular basis to replace any amount that has boiled off. In rare cases where refilling might be impossible to carry out, the dewars can still protect the brain of a patient for up to a month. This is because patients of Tomorrow Bio are stored upside down so that if liquid nitrogen boils out, it won’t affect the brain, as it’s not exposed.
The process of cooling a body to the significantly cold temperature of -196°C can have its drawbacks. Tissue fractures, among other damages, can occur when undergoing significant cooling, and these damages could complicate recovery in the future. “Intermediate Temperature Storage” is the long-term storage of cryonics patients at a temperature that’s warmer than -196°C and colder than the glass transition temperature (around -125°C). Storing the body at a temperature of about -130°C helps to avoid tissue fracturing.
However, if there are benefits to ITS, then why don’t we employ this system instead?
There are a few complications with ITS. Firstly, ITS systems are only filled with about 120 liters of liquid nitrogen, instead of being filled to the top like traditional storage tanks. The liquid is only sufficient for about 5 days of storage at a temperature of -140°C, so needs to be filled much more regularly. What’s more, ITS dewars consume twice the amount of liquid nitrogen compared to traditional methods, which require added resources and checkups to ensure a stable temperature, making it a less reliable and safe system.
While it’s believed that ITS storage could provide a higher-quality cryopreservation, it still involves complex maintenance and higher upkeep costs, which is why Tomorrow Bio does not use it at present. Additionally, a fully stable and functioning storage system has yet to be developed. As long as liquid nitrogen remains the safer and more affordable option, Tomorrow Bio will continue to use it. However, we are actively working to build ITS dewars and will offer it once the option has been developed and perfected over time.
When you consider the future and revival, you hope the earth will be a place worth living in. The choices people and companies make today all impact how our planet will look in the future. Tomorrow Bio acknowledges this and does what it can to contribute to a liveable world. Today, architects and city planners are optimizing urban spaces by adopting modern architecture and infrastructure that increase the quality of life for communities. Urban housing is taking a community-focused approach by using free roofs and walls to increase energy efficiency and air quality. Added greenery in public spaces, like planting trees to avoid ‘heat islands’ during the peak summer months would make for a more fun experience outdoors. Environmentalists and researchers are also working on sustainable solutions for the planet. Investing in sustainable energy, running new road infrastructure, and adopting fresh farming practices, like vertical farming, are all exciting ventures that could pave the way for a bright future ahead.
As scientists are busy trying to make the futuristic environment a reality now, cryonics companies are striving to ensure their members revive to see it. Cryogenic storage dewars at EBF don’t require electricity to store our patients indefinitely—making this a long-term solution for both the company and our patients.
To create the cooling substance, liquid nitrogen, scientists compress air and split it into its individual components—nitrogen and oxygen. While the process uses some energy, it results in a renewable resource that’s incredibly sustainable. As always, as our technology advances, so does our research. If we find a better and more eco-friendly method of preserving patients, we may change our protocols, but for now, this is the one that leaves the smallest environmental footprint behind.
Right now, liquid nitrogen remains the best option for cryopreservation procedures. With this said, we are always researching, developing, and learning new ways to improve our procedures so that optimal revival is available in the future. As the fastest-growing cryonics company in Europe, Tomorrow Bio leads the way for new discoveries to ensure that its members receive the best service possible.
If you are interested in the world of cryonics and are looking to learn more, why not check out our Tomorrow Insight page, filled with some great articles to get a better understanding of what we do here! Otherwise, feel free to join us on Discord to chat all things cryopreservation!
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