In human blood, there is a kind of blood cell that has a miraculous replication and value-added effect, which is the seed of blood cells, i.e. hematopoietic stem cells. Hematopoietic stem cell transplantation is an effective means to cure malignant blood diseases (leukemia, malignant lymphoma, multiple myeloma), aplastic anemia, certain genetic diseases and mid- to late-stage malignant solid tumors. Since the number of hematopoietic stem cells in human blood is very small and concentrated in the bone marrow, early hematopoietic stem cell transplantation is mainly bone marrow transplantation. However, bone marrow transplantation has a major disadvantage because of the strong immune rejection of bone marrow and therefore requires a high HLA match. The probability of matching is 25% among siblings and 1 in 50,000 to 100,000 among non-relatives. As a result, very few patients can actually receive a bone marrow stem cell transplant. Happily, the cord blood of newborn infants contains an abundance of hematopoietic stem cells. Cord blood transplants are comparable to bone marrow transplants in saving the lives of children with leukemia and other patients with compromised immune systems. Clinical studies have shown that the 5-year survival rates for both cord blood and bone marrow transplants are the same; 50% for malignant diseases and 85% for non-malignant diseases. More importantly, cord blood requires less compatibility between donor and recipient. It is less likely to cause severe rejection reactions. Since the first successful cord blood transplant in 1998, doctors around the world have tried to use cord blood transplants instead of bone marrow transplants to treat various diseases with unexpected success. Therefore, proper preservation of umbilical cord blood stem cells for your child will be of great benefit. I. Umbilical cord blood stem cells Umbilical cord blood, also known as placental blood or cord blood, is the blood in the umbilical cord and in the blood vessels near the fetal side of the placenta at the time of fetal birth. Among them, umbilical cord blood stem cells are a kind of primitive cells in umbilical cord blood with differentiation potential, possessing the ability of self-renewal and proliferation, and can differentiate into various cells or tissues under the influence or induction of specific factors. In current research, the hematopoietic stem/progenitor cells in umbilical cord blood are mainly used for the treatment of hematological diseases, including leukemia, lymphoma, anemia, etc. And since the immune function of the stem cells contained in cord blood is not fully developed, it is relatively easy to match, especially among family members. 1. Cord blood stem/progenitor cells Cord blood stem/progenitor cells. CD34 antigen is the main marker for the isolation and purification of HSCs/HPCs, and the CD34+ cell population in umbilical cord blood is higher in quantity, quality and proliferation capacity than bone marrow and peripheral blood, indicating that HSCs/HPCs in umbilical cord blood have a more primitive and stronger proliferation and differentiation capacity. proliferation and differentiation ability. In addition to hematopoietic stem/progenitor cells, umbilical cord blood also contains many other non-hematopoietic stem cells, such as mesenchymal stem cells, endothelial precursor cells and non-restricted somatic stem cells. These cells can be induced to differentiate into osteoblasts, adipocytes, neuronal cells, endothelial cells, etc., which have the potential to be applied to tissue repair, gene therapy vectors and hematopoietic stem cell co-transplantation. II. Preservation of umbilical cord blood stem cells The blood left in the umbilical cord and placenta after the birth of a baby is cord blood. Since ancient times, this blood has been discarded as waste. The current way to collect cord blood is: after birth, the umbilical cord is ligated, cut, and the baby is nursed by a midwife, scrubbed, wrapped, and cared for at the same time, either from the cord blood (in vivo collection) or after the placenta is delivered (in vitro collection). The amount of blood collected by either method can be around 80ml. Cord blood collection does not cause any adverse effects on the baby or the mother, but only collects the cord blood that was originally used as waste. However, it should be noted that cord blood should be processed within 24 hours after collection and should be shielded from ultraviolet light and violent shocks during transport to fully maintain cell activity. The conservator should contact the hospital and the cord blood bank in advance before delivery to ensure the timely and smooth collection of cord blood. 1.Storage of umbilical cord blood stem cells There are two methods commonly used for storage of umbilical cord blood stem cells. One is rapid cooling amorphous curing, which is a rapid or ultra-rapid cooling method that enables the sample to be vitrified at a non-toxic low concentration, and the vitrified method of ultra-low temperature preservation has the advantages of simplicity, speed and efficiency. Studies have confirmed that umbilical cord blood stem cells can also be cryopreserved by the vitrification method. Another method is the slow cooling method, in which the collected cord blood is placed in a freezing solution containing antifreeze (usually glycerol or dimethyl sulfoxide), programmed to cool down to -80°C, and then placed in liquid nitrogen, which has a correspondingly higher cooling rate and is less likely to form ice crystals inside the cells, thus causing less damage to the internal structure of the cells, especially to the cell membrane. Usually, umbilical cord blood stem cells are stored in a refrigerator at -80℃ for a short period of time, while they can be stored in liquid nitrogen at -196℃ for a long period of time. Some studies have shown that there is no significant change in the cell activity and recovery rate of umbilical cord blood stem cells frozen in liquid nitrogen for 6 months, 1 year and 2 years. 2.Recovery of umbilical cord blood stem cells Usually, the frozen cells are taken out from liquid nitrogen, thawed quickly in a water bath at 40℃, centrifuged and the supernatant is carefully discarded, and then serum-containing medium is added for testing or culture. Autologous cord blood stem cell banking is the preservation of autologous cord blood stem cells from infants. After collection, part of the autologous cord blood is used for genetic diagnosis to detect and record all the genetic information and genetic defects of the child, such as susceptibility genes for certain tumors or diseases, etc. It is kept as a personal “biological file” to provide health care advice for the child later in life. The remaining cord blood will be cryopreserved for future use not only by the baby itself, but also by relatives related to the baby. Preserving umbilical cord blood is like saving the seeds of life that can be used to rejuvenate a dying life at some point in the future.