Dextran crosslinked gel

Several types of crosslinked gels [e.g. dextrans (Sephadex), poly(acrylamide) (Bio-Gel P), and poly(acryloy Imorpholine) (Enzacryl)] are used for the separation of biopolymers by thin-layer chromatography. These materials must be swollen in an appropriate buffer/solvent system before spreading as a layer. Laboratory-made layers require modified equipment for their use and afford only modest performance characteristics. 

Sinibaldi [ref. 99] has investigated the hydrolysis polymerization of six metal ions, i.e., iron(III), zirconium(IV), aluminium(III), lanthanum(III), thorium(lV) and titanium(IV), by thin-layer method with dextran and polyacrylamide gels. An acetate buffer (0.5 M) was used as eluent, because the solution was found to eliminate the adsorption or precipitation of hydrolyzed sample solutions which were prepared by adding various amounts of NaHC03 to the solution of a metal ion. The hydrolyzed solution of iron(III) yielded two spots on highly crosslinked gels (Bio-Gel P-2 and Sephadex G-25), of which the faster moved with the speed of the completely excluded marker Blue Dextran, and also... 

Recendy Kaplan and Park studied chemically crosslinked dextran hydrogels for application in the controlled deliveiy of bioactive proteins (Kaplan and Park, 1995). Dextran was functionalized by reacting it with glycidyl acrylate to introduce reactive double bonds. Upon exposure to y-irradiation the functionalized dextran formed a crosslinked gel which could be degraded by dextranase. 

Sephadex, which can also be obtained in a variety of ion-exchange forms (see Table 15) consists of beads of a crosslinked dextran gel which swells in water and aqueous salt solutions. The smaller the bead size the higher the resolution that is possible but the slower the flow rate. Typical applications of Sephadex gels are the fractionation of mixtures of polypeptides, proteins, nucleic acids, polysaccharides and for desalting solutions. 

Dextran gels used as molecular sieves are formed by crosslinking dextrans with epichlorhydrin to give a semisynthetic polysaccharide with a well-defined pore size (Sephadex ). 

We have found that crosslinked dextran gel spheres (9) provide a useful model system with which to study agglutination. 

Dextran Gel Spheres. Crosslinked dextran gel spheres (Sephadex), grade G-200, were obtained from Pharmacia (Montreal). 

Oxidized starch loses its ability to gel, thereby making low Tfi dispersions. Glucose dialdehyde is a glucose oxidation compound used to crosslink agarose (linear) and dextran (branched) for their performance as adsorbents. Oxidized celluloses are a substitute for glues manufactured from animal by-products. 

The selection and chemical modification of the current generation of chemically and physically robust stationary phases with narrower particle and pore size distributions has been based on the developmental effort that has occurred over the past 20 years. Initially chemically modified, deformable polymeric gels were used, such as the crosslinked agaroses, dextrans, or acrylate-based copolymers, but more recently various classes of highly refined type I and type II silicas and other ceramic materials, or new classes of controlled porosity polymeric organic materials have found increasing application. 

Crosslinked dextran gels (for example, Sephadex ) have been used extensively for the purification and fractionation of various biological substances, including the recovery of proteins from liquid wastes and effluent streams.343"-347... 

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