Probumin^® Bovine Serum Albumin (BSA) Powders & Solutions - Frequently Asked Questions

Bovine Serum Albumin (BSA) is an essential life science product with a broad range of utility.  Albumin is one of the most extensively utilized proteins in the medical industry. Its availability, inherent stability, and ligand-binding capability make albumin essential in the development and production of many diagnostic tests. It is commonly used in laboratory and biotechnology applications, especially in cell culture and molecular biology experiments. BSA serves several important functions in these contexts:

• Blocking Agent: Bovine Serum Albumin (BSA) is often used as a blocking agent in assays such as enzyme-linked immunosorbent assays (ELISAs) and Western blots. It helps prevent nonspecific binding of antibodies or other proteins to surfaces like microplates or membranes.
• Stabilizer: Bovine Serum Albumin (BSA) can stabilize certain enzymes and proteins, helping to maintain their activity and structure in various experimental conditions.
  
• Carrier Protein: Bovine Serum Albumin (BSA) can serve as a carrier protein in biochemical experiments. For example, it may be used to carry small molecules or substances that need to be solubilized in aqueous solutions.
  
• Diluent: Bovine Serum Albumin (BSA) can be used as a diluent or buffer component to help maintain the pH and osmolarity of solutions during experiments.
  

BSA is a widely used reagent in the life sciences due to its stability, low cost, and compatibility with many biological systems. Researchers often use high-quality, purified BSA to ensure accurate and reproducible results in their experiments. Our BSA has three applications within Life Science: Laboratory Reagents, Cell Culture, and Diagnostics. In research labs, BSA is often used as a protein standard and Molecular weight standard. In Cell Culture BSA is used as a media additive, to transport nutrients, for cell protection & detoxification. In diagnostics, BSA is used as a buffer component, Stabilizer, Blocking, and coating.

IVD product developers and kit manufacturers who are looking for a BSA supplier with robust supply chain, strong regulatory and quality assurance support, technical and application support, and scalable quantities.

High-grade BSA (bovine serum albumin) is used in life sciences research, biotechnology, pharmaceutical and diagnostics. Many grades of BSA are available with users requiring high consistency, bulk quantities for manufacturing, and technical, application & QA support, typically seeking out reliable producers of high-grade BSA. Some users include:

• Research Laboratories: Academic and industrial research laboratories across a wide range of disciplines use high-grade BSA in various experiments and assays. This includes molecular biology, cell culture, biochemistry, and immunology labs.
• Biotechnology Companies: Companies involved in biotechnology and pharmaceutical research and development use high-grade BSA for the production and testing of biologics, vaccines, and diagnostic kits.
• Diagnostic and Clinical Laboratories: Clinical laboratories and diagnostic companies utilize BSA in IVD assays and tests for medical diagnosis and monitoring.
• Pharmaceutical Industry: Pharmaceutical companies use BSA for various applications, including formulation development, stability testing, and as a component of drug delivery systems.
• Vaccine Development: BSA is commonly used in vaccine development and production, helping to stabilize and preserve vaccine components.
• Protein Purification: In protein purification processes, BSA may be used as a stabilizer or carrier protein.
• Cell Culture: BSA is added to cell culture media to provide essential nutrients and stabilize the growth environment for cells in vitro.
• Immunoassays: BSA is used in immunoassays, such as ELISAs, as a blocking agent to reduce nonspecific binding of antibodies.
• Enzyme Studies: High-grade BSA is used in enzyme studies to stabilize enzymes and maintain their activity.

High-grade BSA is essential in these applications because it ensures the reliability and reproducibility of experimental results and product quality. Researchers and professionals working in these fields rely on the consistency and purity of high-grade BSA to maintain the integrity of their work.

Lateral Flow and Point-of-Care (POC), Immunofluorescence Assay, ELISA Kits, Blood Typing, and DNA/RNA amplification PCR. Bovine Serum Albumin (BSA) is a versatile reagent in assays, primarily used to block non-specific binding sites on surfaces, stabilize reagents, and maintain the consistency and reliability of the assay results. Its use helps improve the specificity and sensitivity of the assay, making it an essential component in many laboratory and diagnostic tests.

Higher grade Bovine Serum Albumin (BSA) like Probumin^® BSA is commonly used in assays, particularly in immunoassays like ELISAs (Enzyme-Linked Immunosorbent Assays) and serology systems to block non-specific binding sites and to stabilize or dilute reagents.

Bovine serum albumin is used as a blocking agent to prevent non-specific binding of antibodies or other proteins to surfaces like microplates or membranes. This is crucial because it helps reduce background noise and ensures that the assay is specific to the target molecule being detected. BSA can be used as a diluent to prepare standard solutions and sample dilutions. When preparing calibration standards or diluting samples, BSA-containing buffers help maintain the desired pH, osmolarity, and stability of the solutions. BSA can stabilize certain enzymes, proteins, and other biomolecules used in the assay. This helps maintain the activity and integrity of these reagents throughout the assay.

In quantitative assays like ELISAs, BSA can serve as a matrix for preparing standard curves. Known concentrations of the target analyte are mixed with BSA to create a series of standards with varying concentrations. These standards are then used to generate a calibration curve to quantify the target analyte in unknown samples. BSA can also be used as a control reagent in quality control and validation of assays. Control samples containing known concentrations of BSA are included to ensure that the assay is performing as expected.

It is important to reiterate that the quality of the BSA can have a significant effect on assay performance, so securing consistent batches of BSA from a reliable vendor is key once the assay is optimized in your application.

Probumin^® BSA is a commonly used bovine serum albumin for buffers, non-specific blocking, protein stabilization and other diagnostic applications. The high quality of our Probumin^® bovine albumin is demonstrated in the usage by companies throughout the world for the manufacture of numerous FDA- and EMA-approved biologics, medical devices, animal vaccines and diagnostic assays.

Merck’s production facility in Kankakee, IL operates under an ISO9001:2015 quality system and follows (EU) No. 142/2011 facility numbers in compliance with European regulations. Each lot of BSA is accompanied by a Certificate of Analysis and Certificates of Origin detailing complete product testing and specifications. Merck can provide an EDQM Certificate of Suitability upon request.

Probumin^®diagnostic grade BSA is highly purified and tested to meet strict quality and performance standards. This product is manufactured by a proprietary heat-shock purification process, using caprylic acid as an albumin stabilizer. It is processed to demonstrate undetectable levels of residual protease activity. This product may be used in development or as a raw material for IVD development, including immunoassays like ELISAs, where BSA is often used as a blocking agent and stabilizer for protein reagents requiring low IgG levels to improve assay specificity and sensitivity. Each lot of Probumin^® BSA is accompanied by a Certificate of Analysis and Certificates of Origin detailing complete product testing and specifications. Merck can provide an EDQM Certificate of Suitability upon request.

Probumin^® Bovine Serum Albumin Diagnostic Grade, 30% solution is a premade BSA product that may be used in development, or as a raw material for IVD development, including immunoassays like ELISAs, where BSA is often used as a blocking agent and stabilizer for protein reagents requiring low IgG levels to improve assay specificity and sensitivity. This product has been processed to demonstrate undetectable levels of protease activity.  This product eliminates the process of preparing a stock solution and is ready to implement into any workflow.  Probumin^® 30% solutions are aseptically filtered and packaged, manufactured by a proprietary heat-shock fractionation process.

Probumin^® BSA is offered in both powder and liquid formats.  Probumin^® 30% BSA solutions are ready for use in any manufacturing procedure by eliminating the need to prepare stock solutions from powder thus saving time, materials, labor, and product loss associated with reconstitution and filtration. 

See our complete Probumin^® BSA solutions offering.

Probumin^® BSA 30% solutions are high purity ready-to-use with no detectable IgG. The premade solutions eliminate the need to prepare stock BSA solutions from powder thus saving time and increasing consistency. The 30% solutions have large lot sizes to ensure product uniformity and minimize incoming material testing and qualification.

That depends on the scale. 

For small scale -

BSA Protocol from powder: preparing a 10% (100 g/L) stock solution of BSA from powder requires:
Dissolve 100 g BSA in 1 L of distilled H2O; to avoid clumping, dissolve by layering the powder on the surface of the liquid. Gently rock or swirl to mix thoroughly without foaming. Processing time: 30-45 minutes.   

BSA Protocol from solution: Starting from a premade 30% solution, measure 0.333L of 30% BSA solution and add to 0.667L distilled H2O to make 1L. Processing time: 5-10 minutes. 

Total time difference between starting from powder or liquid solution is about 30 minutes.

For large scale –

BSA Protocol From powder: preparing a large reagent formulation (900L) starting from powder requires: 

Add 90Kg of powder at a rate of <5Kg every 20 minutes to buffer by layering the powder over the liquid.  Dissolve overnight. Avoid foaming if mixing equipment is used. Processing time: 48 hours.

BSA Protocol From liquid:
Starting from 30% solution to make 900L of 10% BSA storage buffer – prepare base buffer of choice and bring to 600L; measure and add 300L of 30% BSA solution. Processing time: 30-45 minutes.

Total time difference between starting from powder or liquid solution is about 2 days.

Yes, Bovine Serum Albumin (BSA) are commonly used as a blocker and diluent. See these assay examples:

• Galectin-9 competition MesoScale discovery platform (MSD) assay using Probumin^® BSA: Schwartz D. et al. 2022. Characterization of sabatolimab, a novel immunotherapy with immuno-myeloid activity directed against TIM-3 receptor, Immunotherapy Advances, Volume 2 (1) ltac019, https://doi.org/10.1093/immadv/ltac019
• Supersensitive photon upconversion based immunoassay for detection of cardiac troponin I in human plasma Raiko, K. et al. 2021. Supersensitive photon upconversion based immunoassay for detection of cardiac troponin I in human plasma, Clinica Chimica Acta, Volume 523, Pages 380-385 ISSN 0009-8981, https://doi.org/10.1016/j.cca.2021.10.023. 

Yes, Probumin^® solutions are high-grade and consistently manufactured to produce stable cell culture.  In this research example, Probumin^® solution was used to culture a cattle disease organism, Leptospira borgpetersenii serovar Hardjo strain 203.

• Jennifer H. Wilson-Welder, J. et al. 2020. Bovine immune response to leptospira antigen in different novel adjuvants and vaccine delivery platforms, Vaccine, Volume 38(18) Pages 3464-3473, ISSN 0264-410X, https://doi.org/10.1016/j.vaccine.2020.02.086. 

It is good practice to secure BSA products from a well-known manufacturer (not just supplier) of serum. Merck’s Probumin^® bovine serum albumin is manufactured under ISO9001:2015 guidelines and rigorously tested during the process. Some of the more common quality testing specifications are listed below.

Purity Testing

• Purity is important in diagnostic applications since minor components can impact assay performance.

IgG Testing

• can cause interference in some immunoassays
• can be considered a contaminant, and
• is sometimes used by companies to judge purity of a BSA sample

Fatty Acids Testing

• Fatty Acids can sometimes interfere with immunoassays, causing false positive or negative results. Because the heat shock method adds caprylic acid (a fatty acid), this test assures the fatty acid was removed.

Endotoxin Testing

• Produced by Gram-negative bacteria, endotoxin can cause cell shock during cell or tissue culture. This test assures that toxins are not present and indirectly assures the absence of Gram-negative bacteria.

Adventitious Agents Testing

• Added assurance that the product is free of specific bovine viruses, mycoplasma and cytopathic effects, which adversely affect cells.

Protease Testing

• These are a group of enzymes that degrade/digest selected proteins. Customers designing tests for proteins that are sensitive to proteases want to ensure protease free BSA is used. PSA (prostate specific antigen) is an example of protein that is sensitive to proteases.

Bulk capabilities and custom pack sizes of Probumin^® BSA are available for your specific application. Complete the form to receive more information on what we have to offer.

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