Fetal Bovine Serum (FBS) is a widely used supplement in cell culture media, providing growth factors, hormones, and other molecules that support cell proliferation and viability. Gibco, a Thermo Fisher Scientific brand, is a common choice for researchers globally, known for its cell culture reagents.
The Gibco Standard for Quality
Gibco emphasizes rigorous quality control throughout FBS production, beginning with careful sourcing. Serum is obtained from government-approved facilities with healthy animals under veterinary supervision, using aseptic collection techniques to minimize contamination. This vertical integration, where Thermo Fisher Scientific oversees the collection process, helps ensure direct control over initial steps.
Manufacturing involves a closed system to prevent air exposure, which helps maintain low levels of endotoxin and hemoglobin in the final product. After collection, FBS is immediately packed on ice and shipped to audited processing facilities. It undergoes triple 0.1 µm filtration in clean rooms to ensure high sterility and purity. Gibco also prioritizes manufacturing FBS in its country of origin to prevent cross-contamination, and processed serum is never blended from different origins.
Common Gibco FBS Formulations
Gibco offers various FBS formulations, each designed for specific cell culture needs.
Standard FBS
Standard FBS serves as a general-purpose supplement suitable for a broad range of robust cell lines, such as HEK293, HeLa, and CHO cells, in routine cell culture. It provides nutrients and growth factors to support consistent cell growth and proliferation. This formulation is often chosen for foundational studies and basic research due to its reliability and widespread applicability.
Heat-Inactivated FBS
Heat-inactivated FBS undergoes a heating process, typically at 56°C for 30 minutes, to destroy complement proteins. Complement proteins can interfere with immunological assays or be toxic to sensitive cell types, making heat inactivation important for specific research applications. While not always required for all cell cultures, it is frequently used in immunological studies to prevent unwanted immune reactions.
Dialyzed FBS
Dialyzed FBS is processed to remove small molecules. This removal is achieved through a dialysis membrane, which allows smaller components to pass through while retaining larger proteins and growth factors. Researchers use dialyzed FBS in experiments involving isotopic labeling, specific metabolite studies, or when a defined low-molecular-weight environment is required.
Charcoal-Stripped FBS
Charcoal-stripped FBS is treated with activated charcoal to remove hormones, growth factors, and other lipophilic substances. This processing is useful for endocrinology research, hormone-signaling studies, or experiments where endogenous hormones could interfere. The charcoal binds these molecules, allowing for a more defined experimental environment.
ES Cell Qualified FBS
Embryonic Stem (ES) Cell Qualified FBS undergoes specific testing to support the growth of undifferentiated embryonic stem cells. This formulation is screened for parameters such as plating efficiency, colony morphology, and pluripotency to confirm its suitability for maintaining stem cell characteristics. It addresses the unique requirements of sensitive stem cell cultures, minimizing the need for extensive serum lot evaluation.
Critical Quality and Performance Metrics
Researchers rely on specific metrics, often detailed on a Certificate of Analysis (CofA), to assess FBS quality and performance. Low endotoxin levels are a primary concern, as endotoxins, which are components of bacterial cell walls, can trigger inflammatory responses and inhibit cell growth. Gibco aims for very low endotoxin concentrations, with some premium grades having levels as low as ≤1 EU/mL.
Low hemoglobin concentration is another indicator, suggesting proper collection and processing, minimizing red blood cell lysis. High-quality FBS has hemoglobin levels below 25 mg/dL, with premium products often at ≤15 mg/dL. FBS also undergoes extensive testing for the absence of mycoplasma and various viruses, including bluetongue and akabane viruses, ensuring biological safety. Lot-to-lot consistency is paramount, as variations between batches can affect experimental reproducibility.
Selecting the Right FBS for Your Cells
Choosing the appropriate FBS involves considering the specific cell line and experimental objectives. Robust cell lines, such as HEK293 or HeLa, may perform well with standard or “Value” grade FBS, which offers consistent growth for routine applications. However, more sensitive primary cells or fastidious cell lines often require Premium or Premium Plus FBS, characterized by lower endotoxin and hemoglobin levels, and more extensive testing.
The experimental goal also guides FBS selection. For instance, hormone-signaling studies necessitate charcoal-stripped FBS to avoid interference from endogenous hormones. Researchers working with stem cells will opt for ES Cell Qualified FBS to maintain an undifferentiated state. Lot testing is a widely recommended practice, where researchers obtain small samples from several FBS lots and test them on their specific cell lines before a large purchase. This confirms the chosen lot’s ability to support desired cell growth and experimental outcomes, improving reproducibility.
Serum-Free and Reduced-Serum Alternatives
The scientific community explores alternatives to traditional FBS due to concerns regarding lot-to-lot variability, ethical considerations, and the desire for more defined culture conditions. These factors drive the development of serum-free media (SFM) and reduced-serum options.
Serum-free media are formulated with specific nutritional and hormonal components, allowing cells to be cultured without animal serum, which increases consistency and simplifies downstream processing. Gibco offers its own lines of serum-free and chemically-defined media, some entirely animal-origin-free, reducing the risk of adventitious agents and improving reproducibility. These alternatives provide solutions for updating cell culture protocols, particularly for vaccine development, drug discovery, and cell therapy manufacturing.