Physiological conditions are optimal for the growth of primary cells, stem cells and 3D cultures. That’s why it’s important to make sure your incubator closely resembles these conditions as they are in vivo. Incubator parameters vary widely; and while you may not have control over all, there are a few factors you have some control over that will help you achieve optimal cell growth.
While cells will last for weeks at lower temperatures, they won’t survive longer than a few hours if exposed to higher than optimal temperatures. To ensure a steady temperature for your cells, it’s crucial to use an incubator that doesn’t overheat once it’s reached the set temperature. Fans will help in normalizing the temperature throughout the incubator and can speed up the recovery time after opening the door. You can also use a second temperature probe as a safety net, just incase your primary thermometer malfunctions.
In addition to temperature, ensure you keep an eye on humidity levels. If these are too low, water can evaporate quickly causing salt, mineral and solute concentrations to rise to potentially toxic levels. To maintain optimal humidity, avoid the use of a very strong fan, but do maintain a a constant airflow. External water sources are good at increasing humidity levels but a traditional pan will still do an effective job, albeit slower.
Carbon dioxide is present at a concentration of 5% in our lungs and this is often the concentration used in incubators. Different sensors for CO2 are available and modern infrared sensors use a silicone light source that maintains strength after intense use. These sensors recover CO2 concentration the quickest after the door has been opened, reducing the length of time your cells are in suboptimal conditions for.
Another gas that you need to control in your incubator is oxygen. Most cells are in hypoxic environments in vivo, which is why it’s important to maintain sub-atmospheric O2 levels in your incubator. If you want to maintain very low (<1%) O2 levels, you can use a sealed container with premixed gas.
Shut the door!
Gas mixtures, humidity and temperature all change quickly once the door is opened and take a long time to recover once it’s closed. Your organization can go a long way in ensuring that you maintain a constant environment in which your cells can thrive.
Want to learn more about optimal cell growth and harvesting of cells? Watch our on demand webinar Surface selection: Achieving Optimal Growth and Harvesting of Your Cells.