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CO2 Incubators: Mainstays of Cell or Tissue Culture

Carbon dioxide (CO2) incubators are mainstays in traditional biology labs engaging in cell or tissue culture. Incubators provide a stable environment designed to mimic a cell’s natural environment: pH of 7.2 to 7.5, temperature of 37°C, and

by Lab Manager
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Carbon dioxide (CO2) incubators are mainstays in traditional biology labs engaging in cell or tissue culture. Incubators provide a stable environment designed to mimic a cell’s natural environment: pH of 7.2 to 7.5, temperature of 37°C, and a relative humidity of about 95 percent. The CO2 concentration, about 5 percent, is controlled to match physiologic conditions and to maintain a constant pH.

Incubators are used wherever cells must be maintained, expanded, or cultured over periods ranging from a few hours to many weeks.

Deepak M. Mistry, manager for strategic development and marketing at Sanyo (Wood Dale, IL), notes that an upswing in biological therapeutics and stem cell research has created additional demand for high-performance CO2 incubators.

The need to validate incubator operations and cleaning for regulated work is a driving force behind the tight control over conditions inside incubators. Conditions inside an incubator change rapidly when someone opens the door to introduce or remove samples. In some cases, the health or viability of cells may be compromised. Sanyo and other companies use infrared sensors that automatically measure the CO2 concentration and initiate re-equilibration of gas concentration.

Linda CO2 Video

Maintaining cleanliness inside an incubator is of prime importance, particularly for units that house several cell lines at once or change over samples rapidly. Incubators, after all, provide ideal growth conditions not just for cells of interest but for invasive fungi, yeast, and bacteria.

Traditionally, disinfection is achieved via heat or ultraviolet (UV) light. Heat is effective, but energyintensive and stresses materials of construction. UV also works quite well, but only on line of sight: nooks and crannies not directly irradiated may remain contaminated.

Sanyo has pioneered the use of hydrogen peroxide gas for incubator disinfection. Gas permeates every surface area within the box and provides close to 100 percent kill of pathogens. The company claims that cycle time between removal of cells, cleaning, and introduction of new cells is about two hours after peroxide disinfection.

Maintaining the health of cultured cells used in research or biomanufacturing is of utmost importance—not just while they’re in the incubator, but during use and storage. “Since cell lines can take weeks or months to make, they’re very expensive,” Mistry says. “Users expect them to be viable for many months after they leave the incubator.”

BINDER (Bohemia, NY), sees increasing demand for tri-gas incubators – traditional CO2 devices that incorporate oxygen control. Oxygen normally ranges between 15 percent and 20 percent by volume; here O2 is as low as 0.2 percent.

The term “tri-gas” refers to separate hookups for CO2, nitrogen and oxygen.

BINDER specializes in hot air sterilization, which occurs at 180°C. “The next closest, decontamination at 140 degrees, doesn’t remove everything, while disinfection at 90 degrees just knocks down some organisms. You need at least 170 degrees to eliminate not just microorganisms and cells but DNA.”

Hot air sterilization practically eliminates condensation—a breeding ground for microorganisms— and does not require the use of HEPA filtration. HEPA units are expensive and are another potential source of contamination.

C Series

  • Provides hot air sterilization at 180 °C
  • Includes seamless, deep-drawn inner chamber made of stainless steel
  • Features unique BINDER technology (patented air jacket system, etc.)
  • Gives user reliable pH-stability thanks to the drift-free FPI infrared measuring system


GelJacket Series

  • Model 6016 is refrigerated and Model 6014 is non-refrigerated
  • Both models are 10 cu. ft. and feature proprietary active gel insulation technology
  • Incorporates an automatic built-in 90°C moist heat decontamination cycle
  • Includes gVapor™ controlled relative humidity technology, which eliminates the need for a water pan

Caron Products

Galaxy® Series

  • Three sizes, 14, 48 & 170 Liters
  • Multiple options, including high-temperature disinfection, copper interior, oxygen control for hypoxic and hyperoxic needs
  • Advanced and economical models available
  • Offered through Eppendorf North America in the US.

New Brunswick Scientific

Okolab H501-EC

  • Can be used with a single 35mm Petri dish, a glass slide, or chambered 57mm cover glass
  • Automatically adjusts the humidity of the gas stream to minimize evaporative losses
  • Includes simple operation – select your plate adapter and set the sample temperature
  • Allows users to easily regulate media pH levels with the built-in, manual CO2 controller.

Warner Instruments