Serum is a vital ingredient that stabilizes and maintains good quality cell cultures by providing physiological and metabolic conditions that match in vivo biology. Fetal bovine serum (FBS) is the most widely used supplement in cultures because of its excellent growth-promoting ability. FBS provides a rich source of growth hormones, vitamins, trace elements, and proteins to cultured cells. In addition, FBS protects cultured cells by neutralizing potential toxic factors such as endotoxins, pH changes, and proteolytic activity.

FBS composition and quality significantly affect the health and behavior of cell cultures. Because serum is a biological product, manufacturers require stringent quality controls at the collection and distribution stages to develop an exceptional product. Serum manufacturers evaluate serum quality by testing osmolality and total protein content, and checking the presence of common contaminants.  

Cell culture is indispensable in biological research, but it is expensive because of the high price of FBS. One factor considerably driving FBS cost is the country of origin. Depending on the geographic regions, cattle used for serum harvesting may be at risk for diseases. The cost of sera originating from countries such as New Zealand and Australia is usually high because these countries have strict agricultural regulatory laws and animals are free of common diseases such as bovine spongiform encephalopathy and foot and mouth disease. In addition, methods to remove bacterial and viral contaminants without affecting serum integrity could increase the cost. For example, the best quality sera are passed through nanopore filtration systems in aseptic conditions and gamma-irradiated to minimize contaminants.  

Researchers engaging in general cell culture applications often overspend on high quality FBS that has gone through extensive quality checks. While FBS purity is crucial, cell lines have different growth condition needs that do not always necessitate the most expensive product. For example, transformed cell lines such as HEK and HeLa grow in low serum environments without the need for additional micronutrients coming from the serum, such as lipids, essential amino acids, selenium, and other trace elements. In contrast, embryonic stem cell and cardiomyocyte cultures require large quantities of excellent quality serum. Such discrepancies in the nutritional needs of different cell cultures warrant a detailed categorization of FBS products.

MilliporeSigma now offers a cost-effective FBS solution that aligns with industry quality standards. Their FBS offerings are categorized as FBS Classic, Premier, or Select. Each FBS selection category has guidelines that help researchers determine the optimal serum conditions for their cultures based on the required quality parameters, cell culture application, and country of origin. FBS Classic products are well-suited for general cell culture applications, and have undergone rigorous filtering and testing for common bacterial and viral contaminants. FBS Premier products are tailored for biomanufacturing labs that require thorough screening for the absence of specific contaminants. Finally, FBS Select products meet quality standards for specialized cell lines and cultures used to develop immunotherapeutics. This new FBS classification approach provides high-quality and cost-effective solutions to cell culture labs.