Exosomes are extracellular vesicles (EVs) released by cells, which are present in biological fluids as well as cell culture conditioned media. To study exosomes, their purification with high recovery and high specificity levels is a crucial step. It is important to guarantee that the downstream applications are carried with intact pure exosomes.
How to purify exosomes?
Exosomes have specific biophysical properties (density, size, solubility, surface biomarkers, among others) that allow for a multitude of isolation methods. Different isolation techniques are available: ultracentrifugation, precipitation, density gradients, filtration, immuno-isolation, acoustics, or ion exchange chromatography. However, the preferred method is a combination of two powerful techniques, precipitation and size exclusion chromatography (SEC), which provide significant advantages.
What is size exclusion chromatography (SEC)?
SEC is a method to separate particles in solution based on their size. The chromatography column is packed with stable polymeric beads, creating a porous matrix. When the solution containing exosomes is added to the SEC column, the smaller particles will be trapped in the pores, while larger molecules do not enter the pores and elute first. As a result, different elution fractions will contain molecules of different sizes; first the large particles, followed by the smaller particles.
This technique is ideal to achieve highly purified samples in which exosomes are separated from other non-EV components, and it is compatible with both low and high initial sample volumes.
The Exo-spin™ technology combines precipitation and SEC techniques, making it a superior method for exosome separation and concentration, allowing for high specificity and high recovery of exosomes. Exo-spin™ is available in 5 different configurations represented with catalogue codes EX01, EX02, EX03, EX04, and EX05; specifically designed and optimized for different sample types and downstream applications. Try our Exo-spin™ exosome isolation in your research today. First have a look at the table below to select the one that suits you best!
* For cerebrospinal fluid (CSF) and human breast milk samples, validated protocols are available for EX01 only. The protocols are provided in the user guides.
† Highly concentrated exosome samples (e.g. 1x1012 particles/ml) other than blood can also be used.
Please note that the basic protocol requires precipitation followed by further purification with SEC columns. Nevertheless, in cases where exosome concentrations are high, the precipitation step may be omitted. Indeed, removing the precipitation step is essential for applications such as mass spectrometry.