· Possible Cause: Cells are overly trypsinized. Suggested Solution: Reduce trypsinization time or trypsin concentration.
· Possible Cause: Poor cell state. Suggested Solution: Use new cells.
· Possible Cause: Mycoplasma contamination. Suggested Solution: Discard the culture if it has been detected to have mycoplasma contamination, or use mycoplasma elimination reagent.
· Possible Cause: No attachment factors in medium. Suggested Solution: For serum-free culture, be sure attachment factors are contained or use coated culture vessels.
· Possible Cause: No carbon dioxide (CO2) exists in the incubator. Suggested Solution: Monitor carbon dioxide (CO2) pressure and change the CO2 tank timely.
· Possible Cause: Temperature fluctuation in the incubator. Suggested Solution: Monitor temperature in the incubator.
· Possible Cause: Too high toxicity of transfection reagents; Too high passage number of cells; Low purity of plasmids. Suggested Solution: Use transfection reagents of low toxicity or change medium timely after transfection; Use cells of low passage number; Use plasmids of high quality.
· Possible Cause: Big cell damage during thawing or cryopreservation. Suggested Solution: Use new cells.
· Possible Cause: Incorrect osmotic pressure of medium. Suggested Solution: Check the osmotic pressure of complete medium. Most mammalian cells can tolerate osmotic pressure of 260-350 mOsmol/kg and most insect cells can tolerate osmotic pressure of 340-380 mOsmol/kg.
·Possible Cause: Excessive toxic metabolites accumulate in the medium. Suggested Solution: Change fresh medium.