Stem cells are a type of cells and have the commonalities of cells. Under the deep low temperature of -196℃, the life activities of cells almost stopped. Cells still have normal biological activity after cryopreservation and recovery. Chris Bibris of Charlotte, North Carolina, who had his sperm frozen in 1987, and his 33-year-old wife, received intracytoplasmic sperm injection in May 2008. The personnel used the sperm frozen by Bibris 21 years ago to perform in vitro fertilization with his wife's healthy eggs, and it was successful at one time; a domestic conference reported that the umbilical cord blood hematopoietic stem cells after cryopreservation for 16 years can still be resuscitated. The activity rate can reach 80% The above, cultured after resuscitation, can be used for clinical transplantation. These cases show that cells still have normal biological activity after being revived after being frozen for a long time. Stem cells, as a type of cells, also have this characteristic. As for how long stem cells can be stored, further data is needed to confirm , but there is no problem with keeping it for 22 years.
