Tissue cells are inherently suicidal and they require growth factors that not only stimulate replication but are generally required to tell the cell not to undergo apoptosis. Remember that most cells (differentiated or not) know were they are because of local tissue chemical signals; be it adhesion molecules or secreted factors. Without continued stimulus by these factors cells are hardwired to undergo apoptosis because they then sense they are growing in the wrong place (hence in oncogenesis it is not just unregulated replication but molecular mechanisms of overcoming apoptosis for invasion and ultimately metastatic spread). Fetal bovine serum is awash with hormones, paracrine, endocrine and autocrine growth factors which support cells - somewhere in this mix is likely to be a factor supporting survival of your chosen cells. Generally cancer cells respond better to such factors and are not so fussy what the growth factor is!

It provides growth supplements for cells but in some cases it inhibits the growth of cells that are not in contact with serum in vivo like keratinocytes.On the other hand it may be toxic for some sensitive cells and it may be contaminated with mycoplasma and viruses.For more details on pros&cons of serum study the book on cell culture by Freshny.

in some experiments like cell cycle analysis experiments, we need to synchronize the cells, that is, bring them all to one phase of cell cycle. in that case serum free media may be used, which synchronizes cells in G1 phase...in many drug treatment studies also it is used. also for transfection...

Naveen, this situation generally depends on the type of experiment and especially the cell line you are using. While transfection, the medium has to be serum free completely as any FBS may hinder the entry of the plasmid or siRNA into the cell. But sometimes depending upon the cell line, long duration of transfection may lead the cells to stress which ultimately lead to negative transfection. In cases like this either the duration of transfection can be reduced or little FBS maybe added for the cell to survive the stress. :)

In addition to the other comments, consider that when you study proteins phosphorylation and signal trasduction, you will have a huge influence of serum on many pathways (e.g. EGF-R will phosphorylated as a consequence). On the other side most cell types will not grow without FBS. It always a balance between what you need to do to keep the cell in a happy mood and what you want to see.

FBS also protects the cells from shear stress. Alternatively, you could add lipids or pluronic instead.

Tissue cells are inherently suicidal and they require growth factors that not only stimulate replication but are generally required to tell the cell not to undergo apoptosis. Remember that most cells (differentiated or not) know were they are because of local tissue chemical signals; be it adhesion molecules or secreted factors. Without continued stimulus by these factors cells are hardwired to undergo apoptosis because they then sense they are growing in the wrong place (hence in oncogenesis it is not just unregulated replication but molecular mechanisms of overcoming apoptosis for invasion and ultimately metastatic spread). Fetal bovine serum is awash with hormones, paracrine, endocrine and autocrine growth factors which support cells - somewhere in this mix is likely to be a factor supporting survival of your chosen cells. Generally cancer cells respond better to such factors and are not so fussy what the growth factor is!

Be aware that Serum Free Medium is also a "label" for many cell medium providers (like Life technologies SFM series) meaning that you can culture the cell without adding FBS. This is mainly for easing protein purification by preventing the huge amount of albumins in the classical FBS containing media.

In agreement with Professor Pascal Fender's important point - we have only used serum free medium for short term culture when purifying secreted proteins form our target cells ......but for long-term propagation of the cells simple media with FBS is used.

Serum Free Medium is a medium where you have no Serum and is non-specific. It is a kind of medium where you can add the choice of your sera depending upon the requirement for a specific cell line.

FBS or Fetal Bovine Serum contains required growth factors and other necessary ingredients to facilitate sustained cell growth.

Alternatively Serum Free Media is very good for transfection purposes as it minimizes interference with the delivery vehicles. As mentioned in the previous answers, if your tranfsection is going to last long, it is always advised to use serum since absence of serum for a long time may subject the cells to stress and may hinder the transfection.

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Moreover cells growing in a Serum Free Medium tend to be more sensitive.

it is depend on the kin of the experiment and cell line u will use, in our lab we used to use serum free medium for short term kind of experiments, while for long term experiments we prefer to use FBS medium as the cells can could be affected.

Serum is a ill defined cocktail of various factors. As already mentioned, how you use it depends on the specific cell type you are dealing with. Some cells will grow in serum (such as fibroblasts, though not indefinitely) while others will differentiate (such as neural stem cells). In the latter case serum-free media supplemented with cocktails of specific cytokines is required to sustain self-renewal. In some cases, even if the cells can be propagated in serum, its usage should be avoided. For instance in brain tumors it has been shown that cultured resected gliomas expanded in serum lose their stemness signature, their capacity to form tumors in xenografts diminishes dramatically and their expression profile do not mimick anymore the original tumor (Lee et al. Cancer Cell 2006), therefore suggesting that serum propagated cancer lines might not be a good in vitro model to study the disease.

Dear Naveen,

I did my MSc project in vitro. As I know we always use media with 10% FBS. FBS provide media for growth of cells. FBS consist of some growth supplement for cells and without FBS cells are no able to growth normally.If you check the ATCC (atcc.org) website you found that cells need media (RPMI, DMEM, MEM,...) with 10% FBS. So FBS is really importatnt for cells.

Best,

Zahra

Historically, before fetal bovine serum (FBS) was introduced to cell culture, different “tissue extracts” or “embryoextracts” were used to achieve “artificial activation of the growth in vitro” :

Parker, R.C. 1961. Methods of Tissue Culture, 3rd ed. Hoeber-Harper, New York. Chapter VII

Paul, J. 1961. Cell and Tissue Culture, 2nd ed. Livingstone, Edinburgh and London. pp 69-72

They were of course not well defined, bur with confirmed stimulating of proliferating activity. These extracts supplied culture medium with lipids, proteins, metabolites, carbohydrates, purines and pyrimidines, etc. Despite of hormones and growth factors, they were also the potential source of energy supplies for dividing cells.

We should know, that serum, is not only a source of biologically active proteins (hormons, growth factors, ECM proteins, adhesion proteins), but serum is a great source of biologically active nucleic acids: miRNAs, mRNA DNA fragments, which circulate in blood, encapsulated in microparticles, exosomes or transfered by LDL and other proteins.

There is no good solution, the FBS supplementation makes good for cells, but you can never control the cellular environment. FBS depletion, makes cells starving, it will always change their morphology, when it is used for more than several hours. Thus, you can use artificially supplemented media, if you need to control the conditions. Sometimes it is not possible to eliminate FBS, so you must be aware about the bias.

Dear Researchers

thanks for your information, but my question is why we are adding FBS to serum free media, if serum is so vital why don't many recommend serum containing media directly, why we select serum free media and later add FBS in addition?

Serum free media (SFM) is recommended for some specific cell lines only. It can also be used for other cell lines for shorter duration as said by others in this above discussions. We can not use SFM when we have a requirement of healthy cells. FBS contains all the nutrients which requred for the overall cell growth. It depends on the protocol followed, scientist prefer accordingly. In case of adherent cell lines (eg. skeletal muscle cell lines) FBS helps in attachment to the base of flask or plate. SFM causes stress to the cells. I am working on skeletal muscle cell line, where I use SFM (gradually decreasing the concentraion of FBS in media) to produce some amount of stress to convert it into myotubes. Similarly FBS free or decreased concentration of FBS media can be used as per the protocol requirement. It is not always suggessted for SFM to all cell lines because FBS plays a vital role in cell growth.

Different cells have different needs. The media, free of serum can be added to different cells and then you can add the amount of serum that better works for your cell line. The same medium can be used for different cells, but different cells may need different types of serum, like goat, bovine or human serum. In some cases, you need serum free cultures, because the serum may interfeer with your results and then you have to add specific growth factors.

Well the answer to your question with additional information is simple: Serum free media is bought and then FBS is added since it is cheaper compared to buying a medium containing serum. People often prefer to buy basal medium and add ingredients of their choice, this not only cuts down the costs but also you have a more culture/cell specific medium at the end of the day.

I agree with Shashank's answer. By buying basal medium you can made "tailor-made" medium. Moreover, serum quality is variable from one origin to another then provider could not warrant reproducibility over time if serum would be added directly to the medium. The best solution is then that you choose your own serum and keep it frozen for a long time and you thaw aliquot on demand.

Dear Naveen

The attached PDF has valuable informations regarding your question.

Best regards

Dear Ramadan

Thanks for the attachment..its quite helpful and i recommend all others, who contributed in this discussion to read this article...

Dear Naveen

You are welcome. Best wishes and regards

Dear Naveen,

FBS is a source of vitronectin, an attachment factor. In lieu of serum, one can sometimes get away with using fibronectin, vitronectin or collagen coated plates + serum-free medium containing growth factors like EGF, insulin, transferrin selenium, etc.

Who knows if FBS increase the collagen type I production in fibroblast monolayer culture? 

In addition to growth factors, FBS helps in attaching cells to the surface before adding medium in primary culture.

@Ray Kruse iles, when you said that the cancer cell is respond much better than the cell to such factors and are not so fussy what the growth factor is. Does it mean that if we using the THP1 cell line are much better than using HEK cell line for the bioactivity assay ?

is it possible to use 15% FBS in DMEM for unhealthy cells ?

Debenjan, it depends on why the cells are unhealthy.

If unhealthy because of infection with virus, bacteria or mycoplasma, the culture is doomed-bleach and start over.

Cells might be unhappy because they don't like the serum lot you are using; using more would make them unhappier; try another lot?

Cells might be unhappy because they are few in number (clonal growth issues).  In that case, I would use 15-20% serum and not touch them for 1 week to allow colony expansion.

Hope this helps.

I think that we should keep two factors in our mind:

1. The characteristics and metabolic needs of your cells. (Some cells need small or higher quantities of specific growth factors that could be found in FBS to survive. Also, some cells could be cultured in a specific starvation protocol because they can survive without serum for a limited period of time)

2. The content of your serum-free media. (Many people add 0.1% - 1% FBS into their starvation protocol mainly as a carrier protein since without it low concentrations of growth factors will get absorbed by the plastic tubes and dishes. And if your media contains enough quantities BSA or other protein it would not be necessary)

I used before 15% FBS media for cell for propagating frozen cells. I found this could help unhappy cells to propagate fastly. After having your cells propagated , you can use 10%FBS media as usual.