Ficoll
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Ficoll is a neutral, highly branched, high-mass, hydrophilic polysaccharide which dissolves readily in aqueous solutions. Ficoll radii range from 2-7 nm. It is prepared by reaction of the polysaccharide with epichlorohydrin. The term "Ficoll" is a registered trademark owned by GE Healthcare Bio-Sciences AB.[1]
Ficoll columns are used in biology laboratories to separate blood to its components (erythrocytes, leukocytes etc.) Ficoll is normally placed at the bottom of a column, and blood is then slowly layered above the ficoll. After being centrifuged, the following layers will be visible in the column, from top to bottom: plasma and other constituents, mono-nuclear cells (PBMC/MNC), ficoll, and erythrocytes & granulocytes which should be present in pellet form. This separation allows easy harvest of PBMC's. Note that some red blood cell trapping (presence of erythrocytes & granulocytes) may occur in the PBMC or ficoll layer. Major blood clotting may sometimes occur in the PBMC layer. Ethylene diamine tetra-acetate (EDTA) is commonly used in conjunction with ficol separation to prevent clotting.
Ficoll can also be used to separate islets of Langerhans from pancreatic tissue. The separated islets can then be used for transplantation into patients with type 1 diabetes
Because Ficoll layering is a very slow process, similar products which include a column containing a porous high-density polyethylene barrier or "frit" have been developed. These products allow blood to be layered on much more quickly without mixing the Ficoll-like polysaccharide and blood. An example of such a product is the "Accuspin System Histopaque-1077" sold by Sigma Aldrich. It is important to note that the cost of these products is significantly higher than basic Ficoll products. It is also possible to have the Ficoll separating system included in the vacutainer used to collect the blood. Such vacutainers increase the convenience and safety of collecting blood products, but cost 50 times as much as the basic vacutainer.
[edit] Notes
- ^ Ficoll. United States Patent and Trademark Office. Retrieved on February 15, 2007.
