Ficoll
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Ficoll is a neutral, highly branched, high-mass,
hydrophilic A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are n ...
polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wat ...
which dissolves readily in
aqueous An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, also known as sodium chloride (NaCl), in wat ...
solution Solution may refer to: * Solution (chemistry), a mixture where one substance is dissolved in another * Solution (equation), in mathematics ** Numerical solution, in numerical analysis, approximate solutions within specified error bounds * Solu ...
s. Ficoll radii range from 2 to 7 nm. It is prepared by reaction of the polysaccharide with
epichlorohydrin Epichlorohydrin (abbreviated ECH) is an organochlorine compound and an epoxide. Despite its name, it is not a halohydrin. It is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscibility, miscible with most p ...
. Ficoll is a registered trademark owned by GE Healthcare companies. Ficoll is part of Ficoll-Paque, which is used in
biology Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...
laboratories A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which science, scientific or technological research, experiments, and measurement may be performed. Laboratories are found in a variety of settings such as s ...
to separate
blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...
to its components (
erythrocyte Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood ce ...
s,
leukocyte White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera ...
s etc.). Ficoll-Paque is normally placed at the bottom of a conical tube, and blood is then slowly layered above Ficoll-Paque. After being
centrifuge A centrifuge is a device that uses centrifugal force to subject a specimen to a specified constant force - for example, to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby ...
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 and
granulocytes Granulocytes are cells in the innate immune system characterized by the presence of specific granules in their cytoplasm. Such granules distinguish them from the various agranulocytes. All myeloblastic granulocytes are polymorphonuclear, that ...
, which should be present in pellet form. This separation allows easy harvest of PBMCs. Note that some
red blood cell Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...
trapping (presence of erythrocytes and granulocytes) may occur in the PBMC or Ficoll-Paque layer. Major
blood clotting Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a thrombus, blood clot. It results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The process of co ...
may sometimes occur in the PBMC layer. Ethylene diamine tetra-acetate (
EDTA Ethylenediaminetetraacetic acid (EDTA), also called EDTA acid, is an aminopolycarboxylic acid with the formula . This white, slightly water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-solubl ...
) and heparin are commonly used in conjunction with Ficoll-Paque(TM) to prevent clotting and is used as a mononuclear cell separator. At one time, fairly early in the research for diabetes treatment by transplantation, Ficoll was used in an attempt to separate islets of Langerhans from enzyme (collagenase) digested human pancreatic tissue. The theory was that separated islets could then be used for transplantation into patients with
type 1 diabetes Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that occurs when the body's immune system destroys pancreatic cells (beta cells). In healthy persons, beta cells produce insulin. Insulin is a hormone require ...
. In practice, using Ficoll led to difficulty obtaining a pure enough preparation of islets, with enough islet recovery from the original tissue, for safe and effective islet transplantation in humans. Because Ficoll-Paque layering is a very slow process, devices that aid in the most time-consuming step, the overlay, have been developed. One such product is SepMate-50, a specialized tube containing a porous insert that forms a physical barrier between the Ficoll-Paque and blood sample. This allows the blood sample to be rapidly pipetted onto the insert, avoiding the need for overlaying it directly onto Ficoll-Paque. The SepMate insert also reduces the duration of the centrifugation step, and after centrifugation, the top layer containing plasma and PBMCs can be poured into a new tube. Other devices include a column containing a porous high-density
polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bott ...
barrier or "frit." These products allow 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. It is also possible to have the Ficoll-Paque separating system included in the
Vacutainer A vacutainer blood collection tube is a sterile glass or plastic test tube with a colored rubber stopper creating a vacuum seal inside of the tube, facilitating the drawing of a predetermined volume of liquid. Vacutainer tubes may contain addit ...
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.


See also

*
Percoll Percoll is a reagent consisting of colloidal silica particles used in cell biology and other laboratory settings. It was first formulated by Pertoft and colleagues, and commercialized by Pharmacia Fine Chemicals. Percoll is used for the isolatio ...


Notes


External links


Cell Separation Media, Methodology & Applications Handbook
{{Webarchive, url=https://web.archive.org/web/20081205061748/http://www.gelifesciences.com/handbooks , date=2008-12-05 Cell culture reagents Polysaccharides