The word cryo comes from the Greek word “kayos”, which means “frost”. This means keeping in a “frozen state”. It is the process of cooling and storing cells, tissues or organs at very low temperatures to maintain their viability. Cryopreservation is a technique that uses low temperatures to preserve living cells and tissues. With this technique, the tissues can be preserved for a very long time. The science that deals with cryopreservation is known as “cryobiology.” It can be performed at the following temperature: Cryopreservation plays an important role in the tissue and organ bank. With the rapid development of tissue engineering, the cryopreservation of tissue engineering products is of great importance to meet the “ready-to-use” requirement in clinical applications and regenerative medicine. Cryopreservation can be achieved by conventional freezing and vitrification processes. Due to the complexity and intrinsic differences between cells and isolated tissues, evaluating the success of tissue and organ cryopreservation is very different from that of cells and more difficult.
An overview of the cryopreservation methodology is given. The current development of cryopreservation of natural and artificial tissues was also examined. The microscopic terrestrial nematodes Panagrolaimus detritophagus and Plectus parvus are the only eukaryotic organisms that have so far been shown to be viable after long-term cryopreservation. In this case, due to permafrost, conservation was natural rather than artificial. Blood can be replaced by inert noble gases and/or metabolically vital gases such as oxygen, allowing organs to cool faster and requiring less antifreeze. Since the tissue regions are separated by the gas, small expansions do not accumulate and thus protect against bursting. [24] A small company, Arigos Biomedical, “has already recovered pork hearts at 120 degrees below zero,”[25] although the definition of “restored” is unclear. Pressures of 60 atm can help increase heat exchange rates.
[26] Gaseous oxygen infusion/perufflation may improve organ preservation compared to static cold storage or hypothermic machine infusion, as the lower viscosity of gases can help reach more regions of conserved organs and provide more oxygen per gram of tissue. [27] Improved cryopreservation of poultry embryos and sperm. In chickens, success rates remain low due to the use of cryopreserved seeds. Better success rates would lead to greater use of frozen seeds in the poultry industry, which would then facilitate the storage and access of frozen gametes for preservation purposes. Cryopreservation of fertilized eggs may remain difficult, but extraction and cryopreservation of the germ disk of the cells of the fertilized egg separated from the egg itself seem possible. Recent studies have also successfully cryopreserved male and female gonadal tissues in poultry, with subsequent successful transplantation into live recipients. Improved cryopreservation of pig embryos to enable capture of the entire genome, including mitochondrial DNA. This is especially important in Asia, where the number of endangered pig breeds is significant. According to research findings, sperm cryopreservation of marine fish species is more successful than that obtained from freshwater fish, and fertilizers are similar to mammalian species [8]. Vitrification is a shock freezing process (ultrafast cooling) that helps prevent the formation of ice crystals and prevent cryopreservation damage.
Although primary neural cells and cardiomyocytes are commonly used for neuroscientific and cardiological research, no reference protocol for the preservation of these cells has yet been developed. With the discovery of immunosuppressive diets without glucocorticoids,51 pancreatic islet transplantation can be considered an alternative to the treatment of type 1 diabetes. For this reason, the development of island cryopreservation methods is ongoing, but the results are still suboptimal, with a survival rate of less than 50%.51 Cryopreservation has been the main method of preserving biological samples for many years. It has allowed researchers to use rare or valuable samples from decades ago to answer new research questions. Today, it is used to obtain the latest complex cellular models for other scientists in the future and is essential for the storage and provision of biological treatments. In this article, we explore the challenges of cryopreservation and emerging advances that could improve these methods. DMSO was first synthesized in 1866 by Russian scientist Alexander Zaytsev and has been widely used for cryopreservation of cultured mammalian cells due to its low cost and relatively low cytotoxicity.25, 27 Like glycerol, DMSO works by reducing the concentration of electrolytes in the remaining non-frozen solution in and around a cell at a given temperature. However, decreased survival rate and induction of cell differentiation by DNA methylation and alteration of histones have been reported.28, 29 These negative effects of DMSO in cryopreservation create difficulties for its use in routine clinical applications. The results of the studies show that cryopreservation of sperm from marine fish is more effective than cryopreservation from freshwater fish and that fertilization rates are similar to those of mammalian species. Nevertheless, appropriate combinations of cryoprotectants and cooling and rinsing regimes during heating often allow for the successful cryopreservation of biological materials, especially cell suspensions or thin tissue samples.
Examples: Freezing – This method of cryopreservation uses various freezing methods to protect cells from damage and cell death by exposing them to hot solutions of cryoprotective agents. The growing interest in the application of cryopreservation in aquaculture has shown how useful this method could be for the management of fish reproduction, especially when combined with other reproductive technologies such as androgenosis or sex reversal [2]. One of the most important areas where cryopreservation technology is used is that of cryobanks or sperm banks. Cryobanks are currently more advanced for rare pets such as cattle, sheep and goats than for non-pets. In addition, the use of cryobanks is spreading to facilitate the management and conservation of endangered species [24].
