Density Gradient ultracentrifugation

Density Gradient UC schemeDensity gradient ultracentrifugation (UC) is used for the isolation and purification of extracellular vesicles (EV) from cell culture media and biological fluids. Density gradient separation involves the centrifugation of a biological sample through a centrifugation medium of higher or graded density. When exposed to an elevated centrifugal force, sample components migrate through the medium and separate based on their buoyant density. This results in the purification of EV populations through separation from contaminating protein and/or protein-RNA complexes.
Sucrose is a commonly used density centrifugation medium, but has a high viscosity and is hypertonic, making it less ideal for the separation of osmotically-sensitive materials. Therefore, at LECR, iodixanol (OptiprepTM)-based gradients are performed, since iodixanol is capable of forming iso-osmotic solutions at all densities. As such, it will not osmotically stress biological sample components.

 

Reference: Van Deun, J., et al., The impact of disparate isolation methods for extracellular vesicles on downstream RNA profiling. J. Extracell. Vesicles., 3, 2014. (I.F. 2014 = NA) (ranking: NA) (new journal) (citations: >185)