Hematopoietic stem cells play a crucial role in rebuilding the body's blood and immune systems. Umbilical cord blood is rich in hematopoietic stem cells, and its use and value are naturally higher. As a precious biological resource, cord blood, with the intervention of modern medical technology, has shown a very broad application space in clinical practice, and has become a mature means for the treatment of a variety of hematologic and immune system diseases, such as hematologic malignancies, hemoglobinopathies, and bone marrow hematopoietic failure. Therefore, the storage of umbilical cord blood is of great significance, and how to use liquid nitrogen tanks to store umbilical cord blood has also become one of the topics of concern nowadays.

Liquid nitrogen freezing storage is the ideal environment for cord blood storage

Umbilical cord blood has very high requirements for storage temperature and storage environment, only deep cryogenic freezing state can make the cells in a dormant state, the enzymes in the cells are inhibited, and ionization damage will not occur, so that it can be frozen for a long time. Some experts pointed out that “cell frozen storage in -70 ℃ refrigerator can be saved for a year, if the cells are stored in liquid nitrogen, the temperature reaches -196 ℃, theoretically the storage time is unlimited.”

Liquid nitrogen freezing does not affect cell activity

Medical research and clinical practice has proved that cells frozen in liquid nitrogen are still active, the history of bone marrow hematopoietic stem cells has been preserved for more than 40 years, and the preservation of umbilical cord blood hematopoietic stem cells has a history of more than 20 years. The in vitro and animal experiments of Broxmeyer's group, an authority on cord blood stem cell biology in the United States, have shown that cord blood hematopoietic stem cells that have been frozen for more than 15 years can still maintain their original in vitro proliferation, differentiation, expansion and in vivo implantation potential. 2011, a research report published in BLOOD Magazine has shown that the activity of human umbilical cord blood is still very high after 23.5 years of freezing.

Practical application of liquid nitrogen tank for storing umbilical cord blood

Before umbilical cord blood is put into the liquid nitrogen tank for formal storage, in order to prevent the damage of hematopoietic stem cells in the cooling process as well as in the low-temperature environment, it is necessary to add cryoprotectant to the umbilical cord blood hematopoietic stem cells before the cooling process, and in the cooling process, the temperature is reduced slowly and gradually by using the professional computer program, until -90°C, before it can be transferred to the deep cryogenic liquid nitrogen at -196°C for Long-term freezing and storage, so as to ensure the activity of stem cells. It is reported that in the cord blood bank's cryopreservation library, large gas-phase liquid nitrogen tanks are placed, and all the liquid nitrogen tanks are connected by vacuum pipelines, and the terminals are connected to the outdoor 10,000-liter liquid nitrogen storage tower, which can replenish real-time liquid nitrogen for the liquid nitrogen tanks. At the same time, there are closed circuit monitoring, liquid level monitoring, dual-circuit power supply, real-time monitoring of oxygen content and other 24-hour monitoring systems to strictly monitor and ensure the safety of the cord blood storage environment.