The Basics of Fetal Bovine Serum Use in Cell Culture

Fetal bovine serum (FBS), also known as fetal calf serum, is used extensively by both academic biology and industrial researchers as a supplement to basal growth medium in cell culture applications. It is a rich source of proteins and growth factors that support cell growth in culture.

Serum is the amber-colored blood fraction remaining after the natural coagulation of the blood; it is typically further refined via centrifugation, which serves to remove remaining blood cells, coagulation fibrinogens, and low-solubility proteins.

Fetal bovine serum is derived from the blood of a cow fetus, which is drawn via a closed system of collection. Notably, FBS is the most widely used serum supplement for in vitro cell culture (for eukaryotic cells) [1,2].

Bovine serum is classified according to the age of the animal from which the blood was collected [3]:

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As a biological substance, FBS must be carefully taken care of and appropriately stored to avoid degradation. The most effective manner of storage is by keeping the sera frozen.

FBS should be:

• Stored at ≤–10°C
• Thawed between 2–8°C
• Stored and transported in consistent conditions to prevent deterioration

Because serum can be stored for extended periods of time, researchers and manufacturers will often use the same serum lot over a couple of years. However, since FBS is not chemically defined, when it comes time to replenish their supply, they try to source a similar lot with the same kind of specs as the product purchased before.

Thermo Fisher Scientific is committed to providing solutions that help ensure consistency from lot to lot, including FBS fingerprinting and the iMATCH Sera Lot Tool.

Fetal bovine serum used as a supplement in culture media primarily aids in:

• Supplying hormone factors for cell proliferation and growth
• Providing nutrients, trace elements, transport proteins, adherence, and extension factors
• Cultivating a suitable environment for growth with stabilizing and detoxifying factors
• Stimulating cell differentiation

Want to learn more about FBS and vaccines? View our guide to fetal bovine serum in vaccine production

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In addition to providing cells with many growth-enhancing factors (growth factors, hormones, nutrients, etc.), FBS can also protect cells from harmful disruptions, including:

• Large pH shifts
• Proteases
• Toxic agents
• Shear forces
• Agents that would typically break up monolayers of adherent cells (FBS acts to inactivate these agents)

Therefore, when FBS is used, cell growth is typically:

• Rapid
• Consistent and reproducible
• Lacking in undesirable changes in differentiation
• Not hampered by the introduction of detrimental contaminants

While other animal sera, such as horse serum, may be good for certain types of applications, FBS is more universal and can function across a variety of applications, streamlining supply needs.

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• Supply continuity
• Lot-to-lot consistency
• Reproducible results
• Price fluctuation
• Product integrity

Furthermore, researchers rely on FBS that is sterile, filtered, and free of mycoplasma. Thermo Fisher Scientific’s commitment to quality and consistency helps ensure that each lot of Gibco sera meets the needs and standards necessary for optimal cell culture performance and growth.

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Ringer's cell culture medium was developed by Sydney Ringer in 1882 and was the first instance of in vitro cultivation of animal tissue. Over the next few decades, scientific innovation led to the development of the first animal cell cultures, then synthetic media. The 1940s saw the establishment of cell lines, basal media, and research into protein-free media.

In the late 1950s, Theodore Puck first introduced the use of FBS in cell culture with the purpose of encouraging cellular proliferation. Additional studies revealed that, in addition to its ability to stimulate cell proliferation, FBS also contained a multitude of components essential to cell growth and viability (e.g., hormones, vitamins, growth factors, etc.) [5].

For several decades, the use of fetal bovine serum has been ubiquitous across laboratories worldwide. Its popularity has continued to lay in its indispensability as a supplement in cell and tissue culture applications.

To help ensure quality, safety, consistency, and regulatory compliance, Gibco FBS products undergo strict testing parameters, including being ISIA Traceability Certified and Fingerprinting Origin Guaranteed.

1. M Johnson. (2012) Fetal Bovine Serum. Mater Methods 2:117. 
2. Puri G, Chaudhary SS, Singh VK, et al. (2015) Effects of fetal bovine serum and estrus buffalo serum on maturation of buffalo (Bubalus bubalis) oocytes in vitro. Vet World 8(2):143–146. 
3. Definitions of Bovine Serum Types. International Serum Industry Association.
4. Fang CY, Wu CC, Fang CL, et al. (2017) Long-term growth comparison studies of FBS and FBS alternatives in six head and neck cell lines. PLoS One 12(6):e0178960. 
5. Subbiahanadar Chelladurai K, Selvan Christyraj JD, Rajagopalan K, et al. (2021) Alternative to FBS in animal cell culture - An overview and future perspective. Heliyon 7(8):e07686.