What are the benefits and disadvantages of using heat-inactivated FBS in cell culture?
- Heating inactivates complement. Active complement can participate in cytolytic events, contract smooth muscle, release histamine from mast cells and platelets, and activate lymphocytic and macrophage cells. Applications where heat-inactivated serum is recommended include immunological studies and culturing of embryonic stem cells (ESCs), insect cells, and smooth muscle cells.
- Heat inactivation helps to achieve bottle-to-bottle and lot-to-lot stability by neutralizing many factors that can vary largely from lot to lot.
- There aren't necessarily disadvantages to heat inactivation of FBS, but there is some evidence that suggests there may be no added benefit to it unless you are carrying out immune studies.
Note: Heat inactivation is performed in a 56 degrees C water bath for 30 min with swirling every 10 min or so for heat distribution and to lower the degree of protein aggregation/flocculant precipitation. Note: If the time or temperature is exceeded, the serum may thicken to a gel. If this occurs, the serum is no longer usable. Unnecessary heat inactivation can take up time and potentially lead to wasted reagents if a mistake is made during the protocol1.
1. Pellerin, et al., Bioengineering, published in 2021.
Find additional tips, troubleshooting help, and resources within our Mammalian Cell Culture Basics Support Center.
If my FBS arrives partially thawed, can I still use it?
Our studies have shown that short-term storage of thawed FBS at 4 degrees C for up to 28 days causes no decrease in growth or viability performance. FBS stored at 4 degrees C for longer periods of time should be evaluated on a case-by-case basis should this storage condition be necessary.
Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.
Sometimes I notice flocculence in serum. What could it be?
Flocculence may appear in FBS for a variety of reasons. The most common reason is the denaturation of serum lipoproteins. You may observe fibrin, one of the clot-forming proteins present in serum, after the serum has been thawed. This should not affect product performance. To remove the flocculence, transfer the serum to sterile tubes and centrifuge the material briefly at 400 x g. Then filter the resulting supernant along with your media. Do not attempt to filter serum containing flocculence, it may clog filters.
Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.
Why does material precipitate in FBS upon storage in the refrigerator?
Gibco FBS is not pre-aged. When stored at 2 to 8 degrees C, the possibility exists for various proteins and lipoproteins in serum (e.g., cold agglutinins, fibrinogen, vitronectin, etc.) to aggregate, and form either perceptible material or observed turbidity. This should not affect serum performance. We recommend that you store FBS at -20 degrees C and avoid repeated freeze-thaw cycles.
Find additional tips, troubleshooting help, and resources within our Cell Culture Support Center.
