Low cell viability can occur due to various factors during cell culture, such as suboptimal culture conditions, contamination, or issues with passaging. Here are some potential causes and solutions to improve cell viability:
- Culture medium:
- Ensure that the culture medium is appropriate for the specific cell type and provides all necessary nutrients, growth factors, and supplements.
- Check that the medium is not expired, contaminated, or improperly stored. If in doubt, prepare a fresh batch of medium.
- Incubation conditions:
- Verify that the incubator’s temperature, CO2, and humidity levels are stable and within the appropriate range for the cell type. For most mammalian cells, this is 37°C, 5% CO2, and 95% humidity.
- Regularly calibrate and maintain the incubator to ensure accurate and consistent conditions.
- Passaging and cell handling:
- Avoid over-trypsinization, which can damage cells; instead, use the minimum trypsin-EDTA exposure necessary for cell detachment.
- Make sure to neutralize trypsin using serum-containing medium or a trypsin inhibitor after detaching cells.
- Handle cells gently during passaging and avoid excessive pipetting, as mechanical stress can affect cell viability.
- Seeding density:
- Adjust the seeding density during subculture to provide more room for cell growth and avoid over-confluence, which can negatively affect cell viability.
- Note that some cells may have an optimal seeding density for survival and growth, so test different densities to find the best conditions for your cell line.
- Contamination:
- Regularly check for signs of contamination, such as changes in medium color, turbidity, or unusual cell morphology.
- Practice strict aseptic techniques and maintain a clean working environment to minimize the risk of contamination.
- If contamination is detected, discard the affected cultures and start with a new, uncontaminated vial of cells.
- Cell line-specific factors:
- Consider that some cell lines may be more sensitive or require specific culture conditions, such as additional growth factors or specialized media formulations.
- Review the literature and consult cell line-specific guidelines for any special requirements.
By addressing these factors and maintaining proper cell culture practices, you can improve cell viability and ensure the success of your experiments.
