Albumins are globular proteins commonly found in the bodies of all vertebrates. They are one of the longest-known and most studied groups of proteins. The word albumin is derived from the Latin word albus, which means white.
Serum albumin is the most abundant protein in the blood plasma of mammals. Human serum albumin (HSA) is made in the liver and secreted into our blood. Its high concentration in blood plasma is crucial for its primary functions, which include maintaining osmotic pressure to prevent oedema, transporting important molecules like hormones, vitamins, fatty acids and many different drugs, and contributing to the pH buffering capacity of the blood.
Albumin scavenges free radicals to prevent oxidative damage throughout our bodies, and the abundance of albumin in our bloodstream contributes to plasma viscosity, which is important for proper blood flow and circulatory dynamics. Albumin also has a role in wound healing, tissue regeneration and immune regulation. The versatility and abundance of albumin underscore its importance in maintaining health and homeostasis.
It has an exceptionally long circulatory half-life due to its ability to bind a key receptor inside cells (called the FcRn receptor), allowing it to be recycled back into the bloodstream after delivering its cargo to cells. Albumin also binds strongly to the glycoprotein 60 receptor (gp60) on the endothelial cell surface during internalisation into these cells, which can be exploited for drug delivery to tumour cells. The natural benefits of this multifunctional protein have made albumin valuable in a diverse range of medical applications.
What is albumin used for?
In medical research and manufacturing, albumin is widely used for:
- Pharmaceutical formulations: Albumin is often used as an excipient in pharmaceuticals. It stabilises drugs (especially protein therapeutics), enhances solubility, and can be used to extend the shelf-life of products.
- Drug delivery systems: Albumin can enhance the delivery of drugs to target sites in the body due to its natural transport properties and ability to bind to a variety of substances.
- Blood volume expanders: In medicine, albumin solutions are used as blood volume expanders in cases of severe blood loss, shock, or burns. These solutions help maintain blood volume and pressure.
- Culture medium supplement: In cell culture and tissue engineering, albumin is added to culture media as a supplement to enhance their performance by providing essential growth factors and hormones.
- Vaccine production: Albumin can be used in the manufacture of vaccines as a stabiliser, ensuring the vaccine’s effectiveness and longevity.
- Laboratory research: In scientific research, albumin is used as a standard in protein quantification assays and as a blocking agent in immunoassays to prevent non-specific binding.
- Diagnostic applications: Albumin is used in diagnostic kits and reagents. For example, tests for albumin levels in blood or urine can indicate various health conditions. It is also used for antigen and antibody stabilisation, and as a blocking agent.
- Nanotechnology: Albumin-based nanoparticles are being explored for use in targeted drug delivery, especially in cancer treatment, due to their biocompatibility and ability to carry drugs directly to tumour cells.
- Biomedical coatings: Albumin can be used to coat medical devices, such as stents and implants, to improve their biocompatibility and reduce the risk of rejection or infection.
- Tissue engineering and regenerative medicine: Albumin’s biocompatibility makes it suitable for tissue engineering applications. It can be used to create scaffolds that support the growth and differentiation of cells, which is crucial in regenerative medicine.
How is the albumin market evolving?
The global albumin market is set to grow over the coming years, driven in part by increases in liver disease, infections and cardiac surgery. While some of the increase in albumin requirement will be met by plasma-derived albumin, animal-derived albumins are at risk of losing ground to recombinant albumins. Recombinant albumins offer increased safety and consistency, higher performance, and improved regulatory compliance, with the highest quality recombinant albumins being produced by baker’s yeast, Saccharomyces cerevisiae. Some of the drivers for the increased use of recombinant albumins are cell and gene therapies, cell cryopreservation, drug delivery, biologics/vaccine formulations and biotechnology research.