Incubators, also called carbon dioxide (CO2) incubators, are key equipment for biological and medical laboratories. They enable the necessary environmental control and isolate cell cultures from external conditions and contamination. Control focuses on three major factors:
Normal temperature for the human body, 37 degrees Celsius, is an optimum temperature for most cell cultures, although some might require different temperatures. Cells must stay within a narrow temperature range — a few tenths of a degree — to avoid conditions that threaten the cell culture or create a significant delay in growth and impact on schedules.
- Relative Humidity
Relative humidity (RH) levels in the incubator prevent growth medium desiccation. RH can be as low as 75 to 80 percent. More commonly, RH must remain above 90 percent.
- Carbon Dioxide (CO2)
Different cells grow best in environments with pH values that typically range from 7.0 to 7.7. Growth medium includes a pH buffer, often CO2-bicarbonate-based, to keep conditions stable. Chemical reactions in the medium can alter the pH. Control of atmospheric CO2 levels helps maintain steady growth-medium pH.
There are two main technologies for measuring CO2 — infrared (IR) and thermal conductivity. This paper compares them and examines which technology might be best for a given laboratory.