Preserving people in a state of deep cooling in the hope of future revival is called “cryopreservation” or “cryopreservation”. Scientists have been working on creating such technology for many years, but there are still no results, and it is not entirely clear how possible this is. Therefore, at present, cryopreservation of people and large animals is an irreversible process, that is, having frozen a person, it is impossible to revive him, and even more so it is impossible to revive an amputated head or brain. However, Chinese scientists seem to have made a breakthrough in this area – they were able to freeze a fragment of a human brain that had been frozen for 18 months, and after defrosting it remained functional.
Scientists froze part of the human brain for a year and a half, after which it regained its functionality
Cryonics and cryoprotectors — what is this/h2>
A serious problem in cryonics is the freezing of soft tissue. Human cells are known to contain a lot of water, which when frozen turns into ice and damages the cells. For the first time, scientists managed to preserve the integrity of fragments of living tissue after freezing at the beginning of the 20th century. For this, glycerin was used, which prevented water in the tissues from forming ice crystals. Thus, cryoprotectors were discovered that protect cells from destruction during freezing.
In addition to glycerin, scientists began to use many other cryoprotectants that fill organs. These include, for example, ethylene glycol, dimethyl sulfoxide and some other substances. They are able to penetrate cells through the cell membrane, due to which they protect them from mechanical damage. As we have already told, many rich people even froze their bodies in the hope that one day they could be thawed and life restored to them.
However, freezing the human brain was still challenging. Only in 2016, scientists for the first time managed to freeze the brain of a rabbit and preserve it in almost perfect condition. Its cell membranes, synapses and intercellular structures remained intact. Now, employees at Fudan University in China have gone even further. As mentioned above, they managed to freeze for a long time and preserve a fragment of the human brain.
Will freezing the human brain become a reality?
Chinese scientists have managed to develop an effective cryoprotectant substance for freezing the brain. Initially, they conducted many experiments and experiments using various chemical compositions. For organs, scientists used organoids, that is, a cluster of cells grown in the laboratory.
The brain of a rabbit, which was successfully frozen and thawed in 2016. Photo source: rt.com
During the experiments, the authors immersed the organoids in various chemicals and then froze them using liquid nitrogen. Four hours later they were thawed and studied. In this way, the most effective substances were selected that provided reliable protection of tissues from damage by ice crystals. Then the authors of the experiment moved to the next stage and complicated the task – they used larger and more complex organoids, and the freezing itself lasted a longer time.
Ultimately, they managed to find the most effective substance, thanks to which the brain tissue was not damaged even when deep frozen for one and a half years. The composition was named MEDY. Its main components are: methylcellulose, ethylene glycol, dimethyl sulfoxide and component Y27632.
After thawing, the brain even retained pathologies
As reported in the study, after thawing, not only all the cells of the organoids remained intact, but also retained their functionality. Moreover, scientists conducted an experiment with a fragment of a real human brain of a patient with epilepsy, and found that after thawing, the pathologies of the disease were also preserved in the sample. That is, the brain has not undergone any changes at all.
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Of course, the results of the study do not mean that in the near future scientists will be able to freeze a person and thereby prolong life. But on the other hand, scientists will have more opportunities to safely store brain samples, for example, for conducting various biomedical experiments. But perhaps at some point cryonics will also be successful. True, it is unknown whether people will be ready for this, and it is unlikely that it will be available to most people.