Ficoll
Encyclopedia
Ficoll is a neutral, highly branched, high-mass, hydrophilic polysaccharide
which dissolves readily in aqueous
solution
s. Ficoll radii range from 2-7 nm. It is prepared by reaction of the polysaccharide with epichlorohydrin
. Ficoll is a registered trademark owned by GE Healthcare companies.
Ficoll is part of Ficoll-Paque which is used in biology
laboratories
to separate blood
to its components (erythrocytes, leukocytes etc.) Ficoll-Paque is a registered trademark owned by GE Healthcare companies. Ficoll-Paque is normally placed at the bottom of a conical tube, and blood is then slowly layered above Ficoll-Paque. After being centrifuge
d, the following layers will be visible in the conical tube, from top to bottom: plasma and other constituents, a layer of mono-nuclear cells called buffy coat
(PBMC
/MNC), Ficoll-Paque, 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-Paque layer. Major blood clotting may sometimes occur in the PBMC layer. Ethylene diamine tetra-acetate (EDTA
) and heparin are commonly used in conjunction with Ficoll-Paque(TM) 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-Paque layering is a very slow process, devices that aid in the most time-consuming step, the overlay, have been developed. One of these devices includes a column containing a porous high-density polyethylene
barrier or "frit." This product allows blood to be layered on much more quickly without mixing polysaccharide and blood. An example of such a product is the "Accuspin System Histopaque-1077" sold by Sigma Aldrich. The cost of this product is significantly higher than basic Ficoll and Ficoll-Paque products. Another such device, which was recently developed in 2009, aids significantly in the overlay process without the high cost of a porous high-density polyethylene barrier. By dividing the conical tube into two compartments, it overlays blood by slowly leaking blood from the top compartment to the bottom compartment along the walls of the conical tube. An example of such a device is the "BioSep Overlay System" sold by M Biosciences. It is also possible to have the Ficoll-Paque 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.
Polysaccharide
Polysaccharides are long carbohydrate molecules, of repeated monomer units joined together by glycosidic bonds. They range in structure from linear to highly branched. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure,...
which dissolves readily in aqueous
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
solution
Solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
s. Ficoll radii range from 2-7 nm. It is prepared by reaction of the polysaccharide with epichlorohydrin
Epichlorohydrin
Epichlorohydrin is an organochlorine compound and an epoxide. This is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscible with most polar organic solvents. Epichlorohydrin is a highly reactive compound and is used in the production of glycerol, plastics,...
. Ficoll is a registered trademark owned by GE Healthcare companies.
Ficoll is part of Ficoll-Paque which is used in biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
laboratories
Laboratory
A laboratory is a facility that provides controlled conditions in which scientific research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories...
to separate blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
to its components (erythrocytes, leukocytes etc.) Ficoll-Paque is a registered trademark owned by GE Healthcare companies. Ficoll-Paque is normally placed at the bottom of a conical tube, and blood is then slowly layered above Ficoll-Paque. After being centrifuge
Centrifuge
A centrifuge is a piece of equipment, generally driven by an electric motor , that puts an object in rotation around a fixed axis, applying a force perpendicular to the axis...
d, the following layers will be visible in the conical tube, from top to bottom: plasma and other constituents, a layer of mono-nuclear cells called buffy coat
Buffy coat
The buffy coat is the fraction of an anticoagulated blood sample after density gradient centrifugation that contains most of the white blood cells and platelets.-Description:...
(PBMC
PBMC
A peripheral blood mononuclear cell is any blood cell having a round nucleus. For example: a lymphocyte, a monocyte or a macrophage. These blood cells are a critical component in the immune system to fight infection and adapt to intruders. The lymphocyte population consists of T cells , B cells...
/MNC), Ficoll-Paque, and erythrocytes & granulocytes which should be present in pellet form. This separation allows easy harvest of PBMC's. Note that some red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
trapping (presence of erythrocytes & granulocytes) may occur in the PBMC or Ficoll-Paque layer. Major blood clotting may sometimes occur in the PBMC layer. Ethylene diamine tetra-acetate (EDTA
EDTA
Ethylenediaminetetraacetic acid, widely abbreviated as EDTA , is a polyamino carboxylic acid and a colourless, water-soluble solid. Its conjugate base is named ethylenediaminetetraacetate. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ligand...
) and heparin are commonly used in conjunction with Ficoll-Paque(TM) to prevent clotting.
Ficoll can also be used to separate islets of Langerhans
Islets of Langerhans
The islets of Langerhans are the regions of the pancreas that contain its endocrine cells. Discovered in 1869 by German pathological anatomist Paul Langerhans at the age of 22, the islets of Langerhans constitute approximately 1 to 2% of the mass of the pancreas...
from pancreatic tissue. The separated islets can then be used for transplantation into patients with type 1 diabetes
Because Ficoll-Paque layering is a very slow process, devices that aid in the most time-consuming step, the overlay, have been developed. One of these devices includes a column containing a porous high-density polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
barrier or "frit." This product allows blood to be layered on much more quickly without mixing polysaccharide and blood. An example of such a product is the "Accuspin System Histopaque-1077" sold by Sigma Aldrich. The cost of this product is significantly higher than basic Ficoll and Ficoll-Paque products. Another such device, which was recently developed in 2009, aids significantly in the overlay process without the high cost of a porous high-density polyethylene barrier. By dividing the conical tube into two compartments, it overlays blood by slowly leaking blood from the top compartment to the bottom compartment along the walls of the conical tube. An example of such a device is the "BioSep Overlay System" sold by M Biosciences. It is also possible to have the Ficoll-Paque separating system included in the Vacutainer
Vacutainer
Vacutainer is a brand of test tubes specifically designed for venipuncture, which was developed in 1947 by Joseph Kleiner.In phlebotomy the word “vacutainer” has come to be used as a genericized trademark to describe any vacuum-based blood collection vial, regardless of brand. Becton Dickinson...
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.