American biologists for the first time were able to freeze and unfreeze the embryo of zebra fish, which opens the way for the preservation of endangered species and the creation of new ways to combat infertility, according to an article published in the journal ACS Nano.
“Despite huge successes in freezing stem and germ cells, scientists have been unsuccessfully struggling for more than 60 years over the problem of freezing embryos of fish and other vertebrate creatures, which was hampered by the large size of the embryos and the fact that their cells need to be filled with special” antifreeze “molecules, , Many of which are toxic, “write John Bischof of the University of Minnesota in Minneapolis (USA) and his colleagues.
They have been working for several years to create technologies for freezing and defrosting organs and samples of living tissues and cells that allow growing and storing organs for emergency transplantation or for solving other medical or biological problems.
In March of this year, Bishof’s team solved this problem. It turned out that frozen organs can be brought back to life and freed from the shackles of ice by means of special nanoparticles heated to ultra-high temperatures upon irradiation with a laser. These nanoparticles absorb light and microwave radiation and convert them into heat, evenly distributing it over the frozen bio-sample and preventing the appearance of cracks and splits.
Having checked the technology on small tissue samples, biologists decided to go further and tried to use these nanoparticles, which are microscopic columns of gold about 110 nanometers in height, for “resurrection” of embryos of zebra fish (Danio rerio) frozen by direct immersion in a vat filled with liquid Nitrogen.
As these experiments showed, some of the embryos survived and could develop into normal fingerlings of zebra fish, capable of moving independently. This confirmed that embryos of vertebrate creatures can indeed be frozen, and then brought back to life.
As Bischoff and his colleagues suggest, this method can now be used to create biological diversity banks in which already fertilized embryos of rare and endangered fish species, as well as birds, reptiles and amphibians will be stored. Subsequently, humanity can use them to eliminate the consequences of the sixth mass extinction of animals, which began in the modern historical era.