Cell Culture Media Selection: From Basal to Beyond

Cell culture media options today are wide-ranging and variable in order to cater to the most finicky cell types. The good news: the most commonly used cell culture media are often suitable for the most frequently used cell lines. Here is a look at some common cell culture media formulations, along with expert advice on media choices and supplements.

The choice of media composition is ultimately dependent on cell type, but most media include the basic ingredients needed by cells—amino acids, vitamins, glucose/carbohydrate source, inorganic salts—and a buffer, and often a pH indicator dye. Common basal media that contain these ingredients in different proportions include Minimal Essential Medium (MEM), Dulbecco’s Modified Eagle’s Medium (DMEM), and Roswell Park Memorial Institute-1640 (RPMI-1640).

Sreethu Sankar, Product Manager at Proteintech Group, notes that “the most commonly used media formulations are DMEM and RPMI-1640, as most of the cells that ATCC sells are recommended to grow in these media.” Such media are used to grow mammalian and other cell types with supplements that may include proteins, lipids, trace elements, antibiotics, and serum.

These general-purpose media are widely available and compatible with most cell types with the appropriate supplementation. More complex media for specific needs may include other factors such as pyruvate, ascorbic acid, potassium nitrate, or trace elements such as selenium, along with additional amino acids, vitamins, and inorganic salts. Examples include Iscove’s Modified Dulbecco’s Medium (IMDM), and Ham’s F-10, Ham’s F-12, and McCoy’s 5A media. “The classical media formulations are suitable for a variety of common laboratory cell lines and applications,” says Ann Rossi Bilodeau, Senior Bioprocess Applications Scientist at Corning Life Sciences. “When testing media, MEM and RPMI-1640 are good starting points for adherent and suspension cells, respectively.” However, each cell type has its own requirements, so consult the relevant literature to identify the best culture media for each.

Most cell types grown in basal media require supplementation with serum, an ill-defined mixture of proteins and other factors derived from animal blood. However, serum can introduce contamination into cultures, and experimental variability. “Although serum alternatives can mitigate variability and contamination risk, it can be difficult to achieve the same complement of growth factors, hormones, attachment proteins, and undefined elements that contribute to faster cell growth rates in vitro with serum-containing media,” explains Bilodeau. As a result, there is increasing interest among cell biologists in serum-free and reduced-serum culture conditions.

Animal-free media products are increasingly available for clinical research and applications. FUJIFILM Irvine Scientific’s most common media, like their entire BalanCD product line, are designed “to support large-scale commercialization of biotherapeutics while also being suitable for early-stage culture development, mostly to support the discovery of new drug candidates and support researchers studying biological mechanisms or cell biology,” says Tom Fletcher, R&D Director of Process Sciences at FUJIFILM Irvine Scientific. “Because we operate using the popular engineering phrase—“begin with the end in mind”—we try to make using our media as simple as possible, so the transition from early development to scale-up is seamless.”

Media for different stages

Many types of cells thrive in one type of media no matter what the stage of culture, whether seeding, expansion, splitting, or harvest. Other cell types might require modification or supplementation of their standard media for important steps of culture. “For example, removal of serum during the first 24 hours following transient transfection, or addition of Rho-associated, coiled-coil containing protein kinase (ROCK) inhibitors during subculturing of pluripotent stem cells,” says Bilodeau. “And still other applications may require different media altogether to induce or maintain a specific physiology, such as multi-lineage differentiation of pluripotent stem cells.”

Even though different stages of a culture’s development might require different media, there can be advantages to using as few formulations as possible. Reducing the need to switch media also means less handling of cells, and therefore fewer opportunities to introduce contamination or errors. “The ideal case would be to have the same medium for all stages, but there is also a case for purpose-built media,” says Fletcher. “For example, some researchers use an intensified process to get as much out as possible from their equipment and materials, so we developed very nutrient-rich feed formulas that support intensified bioprocessing.”

Specialized media and additions

Bilodeau notes that—after meeting cell growth requirements—factors guiding the choice of media should include your research objectives, and any downstream assay requirements. “As an example, media formulation is often tailored to inducing or maintaining specific cell physiology for primary cells, 3D cell culture, and disease modeling applications,” she says. In some instances, specific additions to media are required for maintaining cell type. “More than the basal media, the defining components are growth factors and other additives that promote cell growth and differentiation,” says Sankar. “For example, stem cells require basic fibroblast growth factor in order to keep them in the undifferentiated state.”

Interest in 3D organoid cultures as a model for human tissues in drug testing and disease research has also seen the development of specialized media formulations. “A considerable amount of [research] is going into formulating media for 3D organoid differentiation and cryopreservation,” says Sankar. “While freezing down 3D organoids, the ratio of cryoprotectant to serum/media is of [the utmost] importance, as variations in this ratio can affect the structure and viability of organoids.”

More tools are also emerging for labs that grow cells in suspension. Currently, FUJIFILM Irvine Scientific is developing media for these cultures, in contrast to adherent and primary cells, which typically require more handling. “We have developed formulas that are part of our BalanCD product lines, for HEK293 or CHO cells, that require less handling and are easier to manage and control, making scaling easier,” says Fletcher. Today’s common cell types will thrive in the media available now, and the list of options for specialized applications continues to grow.