Many adherent cell cultures will cease proliferating once they become confluent (i.e., when they completely cover the surface of cell culture vessel), and some will die if they are left in a confluent state for too long. Adherent cell cultures therefore need to be routinely passaged, that is, once the cells are confluent, a fraction of the cells need to be transferred to a new cell culture vessel. Suspension cells will exhaust their culture medium very quickly once the cell density becomes too high, so these cultures similarly require regular passaging.
IMPORTANT: Although regular passaging is necessary to maintain
animal cell cultures, the procedure is relatively stressful for adherent
cells as they must be trypsinized. We do not recommend passaging adherent
cell cultures more than once every 48 h.
1. Harvest the cells, either by trypsinization (adherent cell cultures) or by centrifugation at 200 x g for 5 min (suspension cell cultures). Resuspend the cells in an appropriate volume of prewarmed growth medium containing serum.
Tip- The volume of medium used to resuspend the cells depends on the spl