For researchers working with cell and tissue cultures, reproducibility is an ongoing concern. An incubator system can help remove a few important variables.
Incubation is essential to cell and tissue culture, but it can introduce various uncertainties researchers should understand. Credit: unoL/Shutterstock
The issue of scientific reproducibility looms large among researchers. Experimental results that cannot be replicated can lead to manuscript rejections, bruising comments from reviewers, and a lot of headaches.i
While the problem is endemic to all of science, few groups are more affected than the biologists and pre-clinical researchers who spend their days coaxing unpredictable cell and tissue cultures toward replicable results.
"Anybody who's done mammalian cell and tissue culture — especially using very delicate cells like stem cells or primary cells — understands how difficult it is to just get consistency from batch to batch, and from experiment to experiment," says Carl Radosevich, Senior Manager of Scientific Applications at PHC Corporation of North America (PHCNA), a life sciences company.
A number of variables impact cell and tissue culture, from reagent and cell-line selection to experimental design and validation strategies.ii One that frequently goes overlooked is the incubator.
Just as no-one chooses to live with the uncertainty of a leaky roof or temperamental air conditioner, cells and tissues in culture prefer stable conditions. A reliable incubator insulates against the environmental perturbations that might undermine experimental work.
A sanctuary for cell culture
The core parameters for a given cell culture are derived from simple physiological principles, such as ideal temperature, sterility and pH. But unlike in the natural world, cells in culture are much less resilient to deviations. Changes of just a few degrees from human body temperature of 37°C can greatly influence protein production or affect the rate of growth for most mammalian cell lines. Similarly, the relatively high carbon dioxide levels in an incubator — typically five percent versus <0.05 percent for the outside world — are essential for maintaining a roughly neutral pH of 7.4. If carbon dioxide levels drop, the culture medium can quickly become more alkaline and inhospitable. Just a few hours in such conditions can lead to cell death.iii
Stable conditions are relatively easy to maintain in a sealed incubator, but that environment is disturbed every time a researcher opens the door. Cell-IQ incubators, from PHCNA, are designed to respond quickly and precisely to most fluctuations in conditions. Their dual-infrared sensors can accurately detect carbon dioxide levels without being influenced by temperature or humidity — variables that can foil other incubator sensor systems. The sensors are coupled to a microprocessor controller that can restore ideal conditions within two minutes, without overcompensating.
Beyond culture conditions, contamination is also a nagging concern for researchers. A 2015 study determined that 11 percent of cell culture-derived sequencing datasets contained evidence of Mycoplasma,iv bacterial parasites that can starve cells of nutrients and affect cell vital functions.
Cell-IQ systems offer a variety of countermeasures to keep such contamination at bay. The inner surfaces of Cell-IQ incubators are composed of InCu-saFe® — an alloy of stainless steel and copper. While the steel lends durability and resists oxidative degradation, Radosevich says, "There's this germicidal copper element. If a Mycoplasma bacterium hits that, it will be killed naturally."
Additionally, Cell-IQ systems expose circulating air to ultraviolet light to kill off unwanted intruders, and they can perform an active hydrogen peroxide vapor decontamination cycle, which can sterilize the incubator chamber within just three hours.
For reliable experimental results, no technology can replace good training and careful laboratory protocols, but a trustworthy incubator can help. "When the cells are in their home, we don't want that home to be another variable," Radosevich says.
To learn more about how incubator technology can reduce the variables inherent in cell and tissue culture, visit the dedicated page at PHC Corporation of North America.
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Olarerin-George, Anthony O, and John B Hogenesch. "Assessing the prevalence of mycoplasma contamination in cell culture via a survey of NCBI's RNA-seq archive." Nucleic acids research
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