Cryogenics isn’t just something we study here at Tomorrow Bio to facilitate human cryopreservation—it involves the production and behaviour of materials at sub-zero temperatures. Without the work done by scientists, engineers, and researchers in multiple industries, society wouldn’t see some of the great technologies today that benefit from cryogenics. In fact, using low temperatures to help treat ailments is a tale as old as time. In 450 BC, Hippocrates suggested using snow to help those who were wounded in battle. Centuries later, scientists have continued to make great advancements in the field by studying the effects of sub-zero temperatures on biological materials. In medicine, the use of cryogenics ranges from MRI machines to cryotherapy and it is largely applicable to the preservation of tissues, cells, and organs. So, what exactly is it and how is it useful?
As mentioned above, cryogenics—often confused with cryonics or biostasis—involves the production and behaviour of material at extremely low temperatures. The cryogenic temperature range is from -150 °C (−238 °F) to absolute zero (−273 °C or −460 °F). This is considered the temperature at which molecule movement comes as close as theoretically possible to ceasing completely. As a result of these extremely low temperatures, the properties of materials, such as thermal conductivity, strength, and electrical conductivity is changed.
Cryotherapy—also known as cryosurgery or cryoablation—was used in the past to heal wounds and alleviate pain. Today, cryotherapy is used to treat skin conditions, such as warts and skin tags, and certain cancer cells and abnormal tissues, in the prostate, cervix, and liver. For skin cancer, the medical practitioner uses liquid nitrogen on the affected area to destroy the abnormal tissue. For tumors and malignancies inside the body, the doctor uses a probe, known as a cryobe, which is attached to a supply of liquid nitrogen. The cryobe is then advanced next to or inside the abnormal cells to ‘freeze’ the cells.
An MRI machine consists of coils, a magnet, and wires that conduct a current. In order for the scanner to function effectively, it requires a coolant that gives the coils superconductive properties, thus enabling the generation of high-intensity magnetic fields. Liquid helium—often used as a cryogenic coolant—is the ideal element for MRI scanners. The liquid is cold enough to provide just the right level of superconductivity required, cooling down the magnets that can then generate images of the patient.
A new trend has developed in recent years, known as whole-body cryotherapy. The therapy takes shape as a walk-in cold sauna where the person receiving the treatment sits for up to 5 minutes while their body is exposed to extremely low temperatures. The therapy was first developed in Japan in the 70s and is believed to have aided with a range of ailments, including rheumatoid arthritis, multiple sclerosis, psoriasis, certain sleep disorders, and depression. Cryotherapy is thought to be popular among sports players, too, with footballers Cristiano Ronaldo and Jamie Vardy known to have used the technique. Whole-body cryotherapy is still in its infancy, so there is a lot more research to be done to fully understand its benefits.
Cryosaunas differ slightly from whole-body cryotherapy. Cryosaunas—also called cryo cabins—are open-ended metal tubes where a person’s head remains outside the sub-zero temperatures. The cooling is carried out through direct exposure to liquid nitrogen, providing the body with the benefits of whole-body cryotherapy without the head being affected.
Cryopreservation is the process of preserving cells, tissues, semen, embryos, organs, and humans by using extremely low temperatures. Cryopreservation reduces the metabolic rate to a point where biological activity is practically at a standstill. Cryopreserved materials are typically stored in liquid nitrogen and can remain in this state indefinitely. The idea behind this technique is to preserve biological material so that they can later be rewarmed and used (or in the case of human cryopreservation—revived, which we will discuss later.)
In order to avoid ice formation at these sub-zero temperatures, cryoprotective agents (CPAs) are used as a type of medical-grade antifreeze. Once the biological material passes the glass-transition temperature (around -130°C), it becomes vitrified, meaning it is now in a glass-like amorphous state. This state is where biological processes stop and cells are preserved indefinitely without decaying. The use of cryopreservation is often seen in tissue and cell preservation, in vitro fertilization (IVF), and cryonics (aka human cryopreservation).
The first successful preservation of mammalian cells happened in 1949 by UK researchers Christopher Polge, Audrey Smith, and Alan Parks. The scientists accidentally combined liquid nitrogen with glycerol on a rooster sperm, and when the sample was rewarmed, they noticed the sperm had regained its mobility. This discovery led to the formation of sperm banking today. Sperm now can be stored for an indefinite period or can be used for sperm donation to help couples and individuals to conceive a child.
Oocyte or egg cryopreservation became a possibility for humans in the 1980s. The method is commonly used for Just like sperm cryopreservation, individuals may also donate their preserved eggs to facilitate others looking to conceive. Moreover, individuals going through treatments such as chemotherapy may opt to have their sperm or eggs preserved so that they are not damaged in the process.
Embryo cryopreservation involves the storing of a fertilized egg at sub-zero temperatures for later use. The procedure was introduced in the 1980s, and by 1984 Zoe Leyland was the first embryo baby to be born. The method is a major aspect of human-assisted reproductive techniques (ART) and has been of great importance to couples going through IVF. During these procedures, extra embryos are often created, which can also be used at a later stage or donated.
Stem cells are the body’s raw materials from which all other cells are generated. Under the right conditions, stem cells divide to form other cells (daughter cells) with a specialized function, such as brain cells, bone cells, and blood cells. Stem cell cryopreservation involves harvesting donor cells, adding cryoprotective agents, rapidly cooling, rewarming, and finally washing and conditioning them for transplantation. They can be used in the treatment of both malignant and benign diseases, and are of significant importance in areas such as cell-based therapies.
Cryonics, or human cryopreservation, is the practice of preserving human bodies at sub-freezing temperatures (-196°C) after their legal death. The aim is to treat the causes of death and restore the patient to good health when medical technology has the capability to do so. Once a person is pronounced legally dead, a specialized medical team (called a standby team) starts the procedure by inducing a state of hypothermia. In doing so, the patient’s temperature is lowered and metabolic activity is reduced. As the body will be exposed to a temperature of -196°C, it’s imperative to avoid ice formation. To prevent this, cryoprotective agents replace the patient’s blood and most of the body’s water is removed. The patient enters a glass-like amorphous state (just as with cell and tissue cryopreservation) where they can remain for an indefinite period of time. While technology isn’t advanced enough right now to rewarm and revive a person, we are optimistic of the chances of revival at some stage in the future.
Cryogenic storage dewars are used in both hospitals and in the field of cryonics and come in various shapes and sizes. The “dewar flask” was introduced by Scottish chemist James Dewar in 1891. The makeup of the dewar applies the physics of a thermos; a container with two or more outside layers with evacuated air between the layers that creates a vacuum gap. The idea of a thermos and a dewar flask is to avoid heat transfer. They are typically used for storage in hospitals where they can contain cryopreserved cells, tissues, semen, and eggs that can later be re-warmed and used.
In the last phase of human cryopreservation, a patient is stored in a tank known as a cryogenic storage dewar. The dewar is refilled periodically with liquid nitrogen and doesn’t require electricity to work. This method secures patients against power outages and makes long-term storage more economically feasible. A commonly used whole-body dewar measures approximately 3 meters high and 1 meter wide. Inside, the patients are placed upside down so that if there are any obstacles in refilling the dewars, the brain could remain protected in liquid nitrogen for months.
Although there have been so many advancements over the last few decades, there is still a long way to go for cryogenics to realize its full potential. So many lifesaving technologies are waiting to be discovered that could help countless people around the world.
The implementation of cryopreservation techniques in organ preservation could be groundbreaking in transplant procedures. Currently, there is a significant shortage of organs available for transplantation worldwide, with waiting lists lasting years for certain procedures. A major contributor to the issue of supply vs demand is the survival rate of organs outside of the body. If an organ could be preserved for extended periods of time, it would ease the time pressure on medical teams to transport it to the recipient, who may be located far from the site of the donor. Cryopreservation may also reduce the rate of discarded organs, which at the moment remains very high.
Before the development of CPR in 1960, a person who suffered a heart attack would have been declared dead. Thanks to medical advancements, however, this is now not always the case. Our definition of death has changed at various points in our history, and what we consider now as ‘doomed’ may be easily savable in 50 or 100 years' time. The work carried out in cryonics is to do just that - to implement future technology to give people a chance to revive and recover from an illness that they wouldn’t survive today.
Cryogenics has such a broad application in multiple industries, many of which you may not have been aware of. With so many developments happening over the years, we at Tomorrow Bio, the fastest growing human cryopreservation company in Europe, are optimistic about what the future holds. Technology is continuously advancing and we believe that cryopreservation is yet to reach its full potential.
If you are interested in learning more about the exciting research happening at Tomorrow Bio or with our partner EBF just take a look at our online editorial Tomorrow Insights, which is sure to answer any questions you might have! Can’t find what you’re looking for? You can also schedule a call with one of our in-house experts who would be more than happy to discuss all aspects of cryopreservation and cryonics in further detail.