Polyacrylamide beads

Suspension polymerization of water-insoluble monomers (e.g., styrene and divinylbenzene) involves the formation of an oil droplet suspension of the monomer in water with direct conversions of individual monomer droplets into the corresponding polymer beads. Preparation of beaded polymers from water-soluble monomers (e.g., acrylamide) is similar, except that an aqueous solution of monomers is dispersed in oil to form a water-in-oil (w/o) droplet suspension. Subsequent polymerization of the monomer droplets produces the corresponding swollen hydrophilic polyacrylamide beads. These processes are often referred to as inverse suspension polymerization. 

Bio-Gel P materials of Bio-Rad are polyacrylamide beads (45-90 fim in diameter) prepared from copolymerization of acrylamide and N,N -methylenebis-... 

Cuatrecasas, P. (1970). Protein purification by affinity chromatography. Derivatizations of agarose and polyacrylamide beads. J. Biol. Chem. 245, 3059-3065. 

Inman, J.K., and Dintzis, H.M. (1969) The derivatization of cross-linked polyacrylamide beads. Controlled introduction of functional groups for the preparation of special-purpose, biochemical adsorbents. Biochemistry 8, 4074-4082. 

Polyacrylamide beads are also available with a wide range of pore sizes and are prepared commercially in a manner similar to that described for poly-... 

Chromatographic separation of proteins on the basis of molecular size (or, more precisely, ease of diffusion) is readily accomplished by size-exclusion chromatography on dextran, agarose, or polyacrylamide beads. 

Carbodiimides are also used to coat glass beads or modified polyacrylamide beads with polyamines. Imunologically active species can also be joined to glass treated with 3-triethylsilylpropylamine using carbodiimides. ... 

Where sufficient antigen is available, e.g., a synthetic peptide, the monoclonal antibodies can be purified easily and quickly by affinity chromatography. Alternatively, purified preparations of monoclonal (e.g., MARK-1, ref. 5) or polyclonal antibodies to rat or mouse F(ab )2 can be used following their immobilization to crosslinked agarose or polyacrylamide bead supports. 

Ligands are coupled by amide bonds to polyacrylamide beads that have free carboxyl (Immunobeads) or amino groups (Affi-Gel 701 Bio-Rad). 

A considerable amount of experience has been gained with a wide variety of materials in the preparation of affinity media, for example, polystyrene beads, cellulose, Sephadex, bead form polyacrylamides, bead form agaroses, and glass beads. With such a wide range of supports available, it would be unwise to recommend any one support for all applications. However, the bead form agaroses display most of the... 

Further purification of the salt-precipitated extract is achieved by passage through Sephadex G-lOO in 0.1 M acetate buffer (pH 4.6) containing 0.2 M NaCl. The main hypocalcemic activity is associated with the descending limb of the last main protein peak. A later communication from the same laboratory (G4) describes the use of 0.1 M formic acid in place of the acetate buffer for the Sephadex G-lOO stage. A further gel filtration step on Sephadex G-lOO in 0.1 M formic acid—1M urea-0.2 M NaCl is then used, and salt and other contaminants are removed by two or more runs on polyacrylamide beads. The active material is finally eluted as a single symmetrical peak. 

T-independent immunogens (reviewed by Feldmann, 1974) usually have multiple copies of the same determinant and are, therefore, capable to react with several receptors on the same B cell ( capping ), which activates the cell. At high concentrations, T-independent immunogens may become polyclonal activators of B cells and act as mitogens of B cells. T-dependency may vary with the host haptenated polyacrylamide beads are T-independent in the mouse (Feldmann et al., 1974) and T-dependent in man (Galanaud, 1979). 

Heitzmann and Kroneis [131] have prepared C02-sensitive fluorescent membranes by soaking cross-linked polyacrylamide beads with a solution of HPTS in hydrogencarbonate and embedding them in silicone rubber (Figure 17-21). The response to CO2 was varied by adding different amounts of hydrogencarbonate, carbonate, and HPTS, all of which act as buffers. The polyacrylamide beads may be omitted, so that an emulsion of the HPTS-carbonate solution in silicone-rubber is obtained. 

Shen and Ryser developed daunorubicin-linked amino-ethyl polyacrylamide beads (Affi-gel 701) or poly(D-lysine) via an Af-cfr-aconityl spacer. The cis-aconityl linkage between drug and carrier was readily hydrolysed at pH 4 but not appreciably at pH 6. Poly(D-lysine) caused 90%... 

Anion and cation exchangers as well as gel filtration can be used to selectively purify mAbsj e.g., sephadex G series sepharoses 2B, 4B, 6B, CVL Sephacryl as well as a variety of agarose or polyacrylamide beads. 

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