2.6.2. Cell Passage

When the cell density reached 80%, carefully absorb and discard the culture medium in the cell culture dish with a pipette gun on the ultraclean workbench, slowly add 3 mL sterile PBS from the edge of the dish with a pipette gun, absorb and discard PBS with a pipette gun, and wash twice. When most of the cells became round and separated from each other, an appropriate amount of complete medium containing fetal bovine serum was added to terminate the digestion. The single cell suspension was made by gently blowing and was centrifuged at 1000 rpm for 5 min, the medium was discarded, and the cells were resuspended by adding a complete medium containing fetal bovine serum. Then, it was divided into culture bottles for further culture and subcultured according to 1 : 3.