What Is Fetal Bovine Serum-Function And Usage?



Wondering what even is fetal bovine serum? You have just landed on the right page then! Fetal bovine serum (FBS) is made from blood taken from a cow foetus during the slaughtering using a closed collecting system. The most popular serum supplement for eukaryotic cell in vitro culture is foetal bovine serum. This is because it contains fewer antibodies and more growth factors, making it more adaptable for use in a variety of cell culture applications.

The Fetal bovine serum contains a significant amount of the globular protein known as bovine serum albumin (BSA). Fetal bovine serum's wide range of proteins keeps cultivated cells in a condition where they can live, grow, and divide.

FBS is not a completely specified media component because it is a biological product, and as a result, its composition changes across batches. Serum-free and chemically defined media (CDM) have been created as a result of this to reduce the likelihood of the transfer of accidental agents. Because many cell lines still require serum to thrive and many serum-free media formulations can only support the growth of specific types of cells, the efficacy of serum-free media is constrained.

The meat industry produces FBS as a by-product. FBS is made from blood drawn in industrial slaughterhouses from cattle that also supply meat intended for human consumption, as is the case with the great majority of animal serum used in cell culture

FBS manufacturing

Blood is drawn from the bovine foetus after it has been taken from the dead cow as the initial step in manufacturing FBS. The blood is drawn aseptically into a blood bag or sterile container, where it is left to coagulate. The standard procedure for collection is a cardiac puncture, which involves inserting a needle into the heart. As a result, there is less chance that the surroundings or the foetus itself will contaminate the serum. The residual blood cells and fibrin clot are subsequently separated from the clear, straw-coloured serum using centrifugation. Before the additional processing is required to make the serum acceptable for cell growth, it is frozen.


Filtration is used in the second step of processing, often in the form of a chain of filters with three sterile 0.1-micron membrane filters serving as the final filter. A thorough Certificate of Analysis is provided together with the aseptically processed FBS, which has undergone rigorous quality control testing. The certificate provides comprehensive test findings as well as details on the serum's country of origin. Commercial suppliers issue different certificates of analysis, but they all typically contain the same information: filtration statement, country of blood collection, country of manufacture, cell growth performance testing, and microbial sterility testing, as well as screening for mycoplasma and virus, endotoxin, haemoglobin, IgG gamma-glut amyl transferase and total protein assays. FBS may also be examined for collection country.


concerns have been raised. The methods for collecting foetal bovine serum have been the subject of dispute. The comprehensive regulation and procedures used to guarantee that serum is obtained ethically are described in-depth in the literature that has been published by the International Serum Industry Association (ISIA). Although the act of killing the dam and the time that passes during the slaughter process before harvesting will cause the foetus to become unconscious or die before serum harvesting, it has been hypothesised that exposing live unborn calves to oxygen could cause them to become conscious before being killed, sparking an ongoing ethical discussion about the practice.

While the Industry Association acknowledges that some organisations have reservations, they contend that since all serum collections are conducted in registered slaughterhouses that are under the authority of the competent authority in the country of collection, it is highly unlikely that a problem would arise.

What Does Fetal Bovine Derum Do?

Fetal bovine serum (FBS) is most usually employed as the leading growth supplement in insect cell culture. It can create excessive foaming, interact with transfection chemicals, and is expensive, but it increases cell development and offers shear force protection crucial in shake and stirrer cultures.

What Is Fetal Bovine Serum Used For?

Due to the great sensitivity of cells cultured in vitro, the foetal bovine serum is commercially accessible from numerous suppliers. Customers typically test certain batches to ensure that they are suitable for their particular cell type. It is customary to adopt the cells to the new batch of material when switching from one batch to another, for instance by combining 50% of the old serum with 50% of the new serum and giving the cells time to adjust to the new material.

To maintain the stability of components like growth factors, a serum is frozen during storage. Some precipitation may be noticed when serum is thawed. This is a typical occurrence, and it has no negative effects on the serum's quality. By transferring the serum to sterile tubes and centrifuging for 5 minutes at 400 g, the precipitate may be eliminated. It is advised that the serum be defrosted in a refrigerator at 2-8 C to reduce the quantity of precipitation.

Why Is Fetal Serum Utilised Instead Of, Say, Adult Or New-Born Berum?

Compared to non-Fetal serum, the foetal serum has a higher concentration of growth hormones and a lower concentration of gamma globulins, or antibodies. These are crucial because growth factors promote cell survival and growth, whereas antibodies might adhere to cultured cells. Additionally, the prenatal serum has lower concentrations of complement proteins (complements) than adult or neonatal serum. These complements lyse cells in culture and interfere with immunoassays, which are both negative outcomes.

What Makes Serum And Plasma Different From One Another?

serum and plasma. Coagulation proteins are present in plasma but not in serum, which is how they vary from one another. Anticoagulants are typically added to the blood before centrifugation to make plasma, but the clotting proteins are left in place. Before extensive/progressive centrifugation or by allowing the blood to clot, the serum is prepared. As a result, a serum is devoid of fibrinogen and proteins related to clotting.


They are complement of 22 proteins that make up 99 per cent of the total protein content of serum and plasma in humans. Numerous proteins make up the remaining 1 per cent. At 50 mg/ml, albumin, the most prevalent serum protein, makes up around half of the total protein mass.

Categories of FBS

Donor Bovine Serum

Bovine donor serum is taken from healthy, living animals that are at least a year old. The donor cattle are meticulously chosen and kept in confined herds, guaranteeing total control over their upkeep, food, and health. All cattle must test zero-negative for Bovine Viral Diarrhoea (BVD) and Infectious Bovine Rhinotracheitis (IBR) before being admitted to the separated herd (BVD). The animals are not medicated or given sub-therapeutic doses of antibiotics; instead, they are employed solely in the production of donor bovine products such bovine serum. To ensure long-term stability and to maintain growth performance consistency throughout its shelf-life, serum products need to be stored and handled properly. Additionally, it is commonly preferred to heat inactivate serum in order to deactivate complement there.

New-born Bovine Calf Serum

Under strict collection and processing guidelines, new-born bovine calf serum is produced from examined, healthy bovine calves that are under 14 days old. In situations when low antibody concentrations are not crucial, it is employed for the routine maintenance of specific cell lines. Fetal Bovine Serum (FBS) can be replaced with New-born Calf Serum (NBCS), which is derived from 3- to 10-day-old calves (FBS). The complement system, antibodies, and other active enzymes are rendered inactive during the heat inactivation process.

Bovine Serum

Protein obtained from cows called bovine serum albumin. In laboratory research, it is frequently used as a reference for protein concentration.

The BSA precursor protein is 607 amino acids (AAs) long in its whole form. The precursor protein is separated from an N-terminal 18-residue signal peptide during secretion, leading to the first protein product's 589 amino acid residues. The mature BSA protein, which has 583 amino acids, is produced by cleaving an additional six amino acids.

Is It Necessary To Heat Inactivate Fetal Bovine Serum?

In the past, serum was heated to 56°C for 30 minutes to deactivate the complement system for immunoassays. However, the procedure is pricy and labour-intensive. As too high of a temperature or for too long of a period of time may damage some growth factors, the procedure must be strictly followed.

Since switching to foetal bovine serum, we have discovered that most cell lines do not require heat inactivated fetal bovine serum


So to conclude, considering the above factors the major drawback of FBS is the possibility of hazardous pathogens such as prions, viruses, Mycoplasma, or other unexplained zoonosis contaminating FBS/media and triggering severe immune reactions following MSC therapy is one of the main worries.


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  • Libny Auguste