||What is Fetal Bovine Serum (FBS)?
FBS is a growth-promoting supplement used in tissue culture for virtually
all types of cells and is also known as foetal bovine serum, and fetal/foetal
calf serum (FCS) . FBS is a complex mixture of nutritional, growth,
hormonal, and attachment (anti-trypsin activity) factors that are essential
for cell propagation. These include a wide variety of proteins, lipids,
salts, minerals, and amino acids. Major proteins include albumin, fetuin,
fibronection, globulins, and transferrin. Furthermore, FBS also appears to
serve as a protective buffer against detrimental changes, such as pH
differences, heavy metals, proteolytic activity, and endotoxin. Other types
of sera include calf serum (CS), goat, and horse serum.
How is it processed?
Raw sera is collected by aseptic cardiac puncture at the abattoir by a
licensed veterinarian. It is quickly refrigerated, and after allowing
sufficient time (usually 24 hours) for clotting , the raw sera is
centrifuged to remove blood cells. It is then prefiltered (submicron
filtered), and finally sterile-filtered through a series of at least three
0.1 um filters. Processing is carefully performed at 4°C to minimize product
degradation, and the FBS is immediately frozen after processing.
Can FBS be used past its expiration date?
Possibly. While we guarantee FBS from five years from the date of
processing, it is most likely viable for several years past that, assuming
that it has been stored properly (at -20°C or below), and not subject to
multiple thawing/refreezing cycles. We recommend that you performance-test
the FBS before usage to confirm viability. If you do not have a protocol for
doing so, please contact us for one. In addition, while is not necessary
for unopened and properly stored FBS, you may also consider sterile
re-filtration (0.1 um) before performance-testing, especially if storage and
handling conditions are uncertain.
How can FBS be heat-inactivated?
Heat inactivation is generally used to inactivate component proteins in the
FBS which may interfere with immunological assays. Heat inactivation also
inactivates certain viruses and may reduce the mycoplasma titer. Insect
cells usually require heat-inactivated FBS. Thawed FBS may be
heat-inactivated by incubating it for 30 minutes in a 56°C water bath. The
FBS should not be agitated during this time. Cool before using on cells.
Should FBS be virus-filtered?
In general, normal processing using sterile filtration (0.1 um) will not
effectively remove viruses. Several companies have developed smaller pore
filters (40 nm) which they claim will remove viruses or reduce viral loads.
This is an option if you have virus concerns. Note that some larger proteins
(e.g., IgM) may also be removed by these smaller pore filters.
Why is there lot-to-lot variability?
As FBS is a complex mixture of biological products, there is extensive
lot-to-lot variation, even within the same donor herd.
Why are these specific cell lines tested?
We test on five cell lines-many more than our competitors. BHK-21 and COS-7 are
workhorse cell lines that are widely used in tissue culture. The HeLa cell
line is another widely used cell line that is also an excellent for
identifying high quality serum which supports better cell attachment and
growth. The L-292 cell line is very sensitive to toxins. Sf9 is an insect
cell line that requires high-quality FBS to generate a high baculovirus
titer. In summary, our performance testing is extremely comprehensive-only
the highest quality FBS will pass.
Why is your FBS is not working with my cells?
First, ensure that FBS is recommended for your cell line. For example, calf
serum (CS), and not FBS, is advised for NIH/3T3 cells. We recommend
consulting websites such as ATCC (www.atcc.org)
and DSMZ (www.dsmz.de)
for media requirements and culturing conditions for specific cell lines.
Tissue culture difficulties may be due to a wide variety of problems, such
as poor aseptic technique, and sub-optimal culturing conditions. Otherwise,
due to batch-to-batch variation, certain cell lines may require specific
growth and/or attachment factors that may not be present in any particular
lot of FBS.