Magnetic techniques for the isolation and purification of proteins and peptides
Ivo Safarik and Mirka Safarikova
Superparamagnetism is a phenomenon by which magnetic materials may exhibit a behavior similar to paramagnetism even when at temperatures below the Curie or the Neel temperature. This is observed in very fine particles, where the energy required to change the direction of the magnetic moment of a particle is comparable to the ambient thermal energy. At this point, the rate at which the particles will randomly reverse direction becomes significant.
Maghemite (Fe2O3, γ-Fe2O3) is a member of the family of iron oxides. It has the same structure as magnetite, that is, it is spinel Ferrite and is also ferrimagnetic. Maghemite can be considered as an Fe(II)-deficient magnetite.
Ferrites are electrically non-conductive ferrimagnetic ceramic compound materials, consisting of iron oxides such as Hematite (Fe2O3) or Magnetite (Fe3O4) plus other metal oxides. In saturated state they conduct a magnetic flux very well and have a high magnetic permeability, which allows them to store stronger magnetic fields than iron, and are known as ceramic magnets. (from wikipedia)agarose
Agar is a heterogeneous mixture of two classes of polysaccharide: agaropectin and agarose . Although both polysaccharide classes share the same galactose-based backbone, agaropectin is heavily modified with acidic side-groups, such as sulfate and pyruvate. The neutral charge and lower degree of chemical complexity of agarose make it less likely to interact with biomolecules, such as proteins. Gels made from purified agarose have a relatively large pore size, making them useful for size-separation of large molecules, such as proteins or protein complexes >200 kilodaltons, or DNA fragments >100 basepairs. Agarose can be used for electrophoretic separation or for column-based gel filtration chromatography.
Chitosan is a linear polysaccharide composed of randomly distributed ß-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit).
Carrageenans (pronounced [ˌkærəˈgiːnəns]) are a family of linear sulphated polysaccharides extracted from red seaweeds.
There are three main commercial classes of carrageenan:
Kappa – strong, rigid gels. Produced from Kappaphycus cottonii
Iota – soft gels. Produced from Eucheuma spinosum
Lambda – form gels when mixed with proteins rather than water, used to thicken dairy products. The most common source is Gigartina from Southern Europe.
Purified forms of alginate are used in antacid preparations such as Gaviscon®, Bisodol®, Asilone®, and Boots Own® tablets. Alginate is used extensively as a mold-making material in dentistry and prosthetics, and in textiles. It is also used in the food industry, for thickening soups and jellies. Calcium alginate is used in burn dressings that promote healing and can be removed painlessly.
Also, due alginate’s biocompatibility and simple gelation with divalent cations, it is widely used for cell immobilization and encapsulation.
magnetically stabulized fluidised beds (MSFB)
Preparation of magnetically susceptible polyacrylamide/magnetite beads for use in magnetically stabilized fluidized bed chromatography
magnetic solid phase extraction (MSPE)
Magnetic solid-phase extraction
Authors: Safarkova M.1; Safark I. http://dx.doi.org/10.1016/S0304-8853(98)00566-6
Magnetic solid phase extraction of non-ionic surfactants from water
Magneto-Archimedes levitation and its application
One of the most remarkable characteristics of magnetic levitation is that there is only one position in which an object is stably levitated. When a levitating object in magnetic fields is moved away from a position of equilibrium, a restoration force is at work. This stable point is determined by its volume magnetic susceptibility and density. Therefore, different substances levitated in the field have different equilibrium positions of levitation and can thus be separated. http://www.riken.go.jp/lab-www/library/publication/review/pdf/No_44/44_159.pdf