Relative Humidity in Xvivo System Incubators
New Concepts and Practices with the Risk-based Approach
We are all taught to do cell biology in room air conditions with room air CO2 incubators. This is technology that hasn’t changed in 60 years. We filled up a big pan with water inside, and then spent a lot of time dealing with the literal fallout: condensation problems, and the microbial swamp in the pan. We had to lug that swamp out to empty it, disinfect it, autoclave it, refill it, and repeat.
Xvivo System Incubators are not in room air, but in a closed system, and allow extremely fine control of gases and relative humidity (RH). You don’t need that big pan full of water. You might not need much water at all.
In fact, too high RH in a closed system can:
- Saturate the filters and waterlog the sensors
- Cause sensor readings to be inaccurate
- Contribute to microbial growth risk
It can also cause water to condense all over the glovefront, which prompts large-scale cleaning, resulting in increased risk of disinfectant fumes to your cells and increased risk of degradation of gloves and other plastics.
Use Water Wisely
Rather than filling up the pan, place small dishes of sterile water in the pan on the bottom shelf.
Start with 1 or 2 dishes (100mm culture dishes) and see how long the water lasts. If you need more, add another dish.
Your infusion rate of dry gases from the tanks and the frequency of door opening events will determine how long it lasts. Use the pan to catch spills rather than as a pool. With a capped bottle of sterile water kept in the corner of the processing chamber, you can top off the dishes when you routinely handle your cells.
Some customers prefer to use more media in their cultures (due to evaporation) rather than have the risks associated with higher chamber RH levels.
Whenever applicable, we recommend customers perform feasibility studies on their process to determine the lowest RH needed.
The Xvivo Has Controls to Automatically Limit RH
Always keep the relative humidity limit controls for incubators and processing chambers ON.
Set the RH limit controls to:This allows the Xvivo to control the humidity by infusing fresh, dry gases.
65% in incubator chambers
50% in processing chambers
Damage from water accounts for more than half of all service calls.
This risk-based use of controlled relative humidity works with the Xvivo System to reduce gas usage, reduce microbial growth risk, and reduce risks to equipment and cells.
About the Author
Alicia D Henn, PhD, MBA
Alicia Henn has been the Chief Scientific Officer of BioSpherix, Ltd for two years. Previously, she was a researcher at the Center for Biodefense Immune Modeling in Rochester, NY. Alicia obtained her PhD in molecular pharmacology and cancer therapeutics from Roswell Park Cancer Institute in Buffalo, NY and her MBA from the Simon School at University of Rochester in Rochester, NY.