How can I dissociate my cells from the cell culture plates when I cannot use trypsin?

In most cases, EDTA will detach the cells as efficiently as trypsin, and afterwards the cells will be less sensitive (e.g., to pipetting) as they are following dissociation using trypsin. CHO cells can be detached with EDTA very efficiently.

Recommended protocol:

  1. Remove the culture medium
  2. Wash the cells with PBS buffer (without calcium and magnesium)
  3. Remove the PBS completely
  4. Add PBS containing 5 mM EDTA (pH 7.6)
  5. Incubate for 5–15 min
  6. Use a 1 mL pipette to resuspend the cells until the aggregates are dissociated

Make sure that the PBS buffer does not contain any divalent ions. Also, pipetting the cells rigorously to dissociate the cell aggregates does not pose a problem.