In a 2012 report, Global Industry Analysts in San Jose, California forecast a growing market for carbon dioxide (CO2) incubators. That comes as no surprise given this technology’s laundry list of applicable fields, which includes cell and tissue culture, protein synthesis, and much more.
According to Charlie Villano, product manager for Eppendorf North America (Hauppauge, NY), “Cell-culture scientists are always trying to recreate in vivo conditions for optimal cell growth, recreating ‘in the body’ cell environments.” As an example, he talks about using CO2 incubators in “cell-based and tissuebased therapies, especially with the advances in personalized medicine.”
How a CO2 incubator gets used also changes as researchers face novel experimental challenges. One such challenge, noted by Villano, comes from working with suspensions of cells in a CO2 environment. In such cases, he says, “Customers are placing shakers inside of CO2 incubators instead of using spinner flasks, which are more aggressive and produce shearing forces and higher cell death than shaking in a standard shake flask inside of a CO2 incubator, especially with stem cells.”
Learning more about the most nurturing environments for growing cells drives changes in incubator technology. “Historically, cell culture has been performed with ambient air containing 19 percent oxygen with only control of CO2 levels required,” Villano explains. “Recently, cell-culture scientists have recognized that cells grow better under hypoxic conditions or physiological levels of oxygen that are below 10 percent.” That requires a CO2 incubator that includes oxygen control. Villano says, “Additional research with tumors in oncology requires conditions below 1 percent, with control of some CO2 incubators at levels of 0.1 percent O2 control.”
Other vendors see similar trends. For instance, Deepak M. Mistry, director of strategic development and marketing at Panasonic Healthcare Company of North America (Wood Dale, IL), says, “There’s more interest in multi-gas incubators.” He adds, “We’re seeing more people using CO2 incubators for stem cells and cell therapy, and that requires highly accurate maintenance of the CO2 and O2 levels.”
To keep those levels accurate, scientists often seek incubators with real-time monitoring. “This can include real-time detection of CO2 and pH, possibly even monitoring each cell plate,” Mistry says.
Keeping it cozy
Many users require more than one CO2 incubator. For instance, Marissa T. Cooke, the research operations manager who oversees the stem cell core and the McDevitt Laboratory at the Georgia Institute of Technology in Atlanta, says, “We use seven CO2 incubators.” When running so many devices, some features turn out to be crucial. As Cooke says, “Features that matter most are those that maintain sterility, such as nonreactive surfaces, easy-to-use decontamination cycles, etcetera.”
To keep an optimum environment for cells, other factors must also be maintained. For example, Villano recommends: “Customers should check CO2 and O2 levels with an independent analyzer or Fyrite tester on a periodic basis. With time, all incubators require calibration to maintain the correct measurement of chamber environments.” Temperature, when included as a controllable option, should also be tested.
Finding the right features
When searching for a new CO2 incubator, Villano recommends thinking beyond CO2 control by answering this list of questions:
- Will you also need to control O2 levels?
- Will you need to incubate cells at or near ambient conditions, requiring a cooling option to work at these temperatures?
- Are you looking for an easy way to minimize potential contamination issues by choosing an easyto- clean incubator together with a high-temperature decontamination cycle?
- Do you want to stack your incubators or select smaller, benchtop units to maximize lab space?
- Is it more efficient for you to dedicate a smaller incubator—say, a 14-liter one—to hypoxic conditions for difficult primary cells instead of dedicating a standard-size incubator for special cell applications?
- Do you need multi-doors to improve recovery time after openings, reduce gas consumption, and decrease the chances for contamination?
Mistry adds to the last point: “Do you put cells in and only open the incubator every five days or every hour? For more frequent opening, you need something that recovers quicker.” That is, a frequently opened incubator needs faster rates of rebalancing all the crucial environmental factors. In an incubator that stays closed more, it might not pay the user to spend the money for faster recovery rates.
As an additional point to consider, Villano suggests that users “select an IR sensor for more direct measurement of CO2 levels versus the older TC—thermal conductivity—that requires more periodic calibration.” Mistry adds, “The more sensitive the cells you’re working on, the more you need to look at the sensor technology. Ask the supplier to convince you what type of sensor would work best for you.”
Perhaps the trickiest part of researching incubators involves some soothsaying. As Mistry explains, “Being an end user myself back in the day, I would say that you should consider what you are doing now and what you will be doing five years from now.”
Plus, getting the best CO2 incubator for a particular application involves more than the kinds of cells that will be kept. It also depends on what devices hold the cells. Mistry says, “We did a customer study that showed that the same cubic capacity lets you keep more of some flasks than others, depending on the design.” So the shape of the cubic space impacts the overall capabilities of an incubator.
In a GMP environment, other factors come into play. “In this case, users benefit from a product that can be easily validated for temperature, gas levels, and so on,” Mistry says. For each instance, the best CO2 incubator provides the needed balance of features for today and tomorrow.
For additional resources on CO2 Incubators, including useful articles and a list of manufacturers, visit www.labmanager.com/incubators