Poly immobilization

Multienzyme electrodes can increase sensitivity from micromolar to nanomolar detection levels (53,57). In this case the substrate is converted to a detectable product by one enzyme, then that product is recycled into the initial substrate by another enzyme resulting in an amplification of the response signal. For example, using lactate oxidase and lactate dehydrogenase immobilized in poly(vinyl chloride), an amplification of 250 was obtained for the detection oflactate (61). 

The Zincke reaction has also been adapted for the solid phase. Dupas et al. prepared NADH-model precursors 58, immobilized on silica, by reaction of bound amino functions 57 with Zincke salt 8 (Scheme 8.4.19) for subsequent reduction to the 1,4-dihydropyridines with sodium dithionite. Earlier, Ise and co-workers utilized the Zincke reaction to prepare catalytic polyelectrolytes, starting from poly(4-vinylpyridine). Formation of Zincke salts at pyridine positions within the polymer was achieved by reaction with 2,4-dinitrochlorobenzene, and these sites were then functionalized with various amines. The resulting polymers showed catalytic activity in ester hydrolysis. ... 

The target was immobilized on monodisperse macroporous poly ((A-methyl)aminoethyl methacrylate-co-methyl methacrylate-co-ethylene di-... 

The mixture of deprotected amino acid derivatives in solution was then immobilized onto a polymeric solid support, typically activated 5-)xm macroporous poly(hydroxyethyl methacrylate-co-ethylene dimethacrylate) beads, to afford the chiral stationary phases with a multiplicity of selectors. Although the use of columns... 

Poly (p-nitrophenyl acrylate)-coated wide-pore glass (WPG) was also used as an activated carrier for the immobilization of biospecific ligands and enzymes, A detailed description of properties of these sorbents and catalysts as well as some specific features of their functioning is given in Sect. 6. 

Porous glass (PG) modified with covalently adsorbed poly(p-nitrophenyl acrylate), as described in Sect. 4.1, turned out to be a highly suitable carrier for immobilization of various biospecific ligands and enzymes. When the residual active ester groups of the carrier were blocked by ethanolamine, the immobilized ligands when bound to the solid support via hydrophilic and flexible poly(2-hydroxyethyl acrylamide). The effective biospecific binding provided by the ligands... 

Immobilization of A and B blood group oligosaccharide haptens and preparation of immunoadsorbents with specificity to anti-A and anti-B antibodies has been carried out with the use of poly acrylate-coated PG (WPG-PA) [124]. Prespacered A and B-trisaccharide-fl-aminopropylglycosides were used for the synthesis. WPG-PA (1 g) quantitatively binds both haptens (2 pinole) whereas some other activated affinity supports (for example, CNBr-Sepharose 4B) do not. On the other hand, glycidoxypropyl-silica binds prespacered haptens completely but these materials reveal no specific adsorptivity. 

It should be noted that by immobilizing the metal complex catalysts on carbochain polymers it is possible to prepare polymer-polymer compositions using PVC, PMMA, poly(vinyl acetate), etc., as the polymeric fillers [286-287]. 

It is not surprising then that the first reported surface mediated reaction made use of vicinal dihalides. In addition to poly-p-nitrostyrene immobilized metallo-porphyrins and viologens were found to be catalytically active. Recently,... 

Chen H, Zhang Z, Chen Y, Brook MA, and Sheardown H. Protein repeUant silicone surfaces by covalent immobilization of poly(ethylene oxide). Biomaterials, 2005, 26, 2391-2399. 

The next two examples illustrate more complex surface reaction chemistry that brings about the covalent immobilization of bioactive species such as enzymes and catecholamines. Poly [bis (phenoxy)-phosphazene] (compound 1 ) can be used to coat particles of porous alumina with a high-surface-area film of the polymer (23). A scanning electron micrograph of the surface of a coated particle is shown in Fig. 3. The polymer surface is then nitrated and the arylnitro groups reduced to arylamino units. These then provided reactive sites for the immobilization of enzymes, as shown in Scheme III. 

FIGURE 3 Scanning electron micrograph (1200x magnification) of the surface of a porous alumina particle coated with poly(diphenoxy-phosphazene). Surface nitration, reduction, and glutaric dialdehyde coupling immobilized enzyme molecules to the surface. (From Ref. 23.)... 

Allcock, H. R., and Kwon, S., Covalent linkage of proteins to surface-modified poly(organophosphazenes) Immobilization of glucose-6-phosphate dehydrogenase and trypsin, Macromolecules. 19, 1502, 1986. 

There are several reasons why these cements are bland. Acid irritation is probably minimal. Poly(acrylic acid) is a weak add and, in addition, because of its high molecular weight will not readily diffuse along dentinal tubules and is also immobilized by phosphatic material in these tubules. Moreover, once set these cements rapidly become neutral. 

Immobilized lipase Covalent binding on poly- Olive oil hydrolysis... 

A semi-interpenetrated network was obtained by bulk polymerization of 2-hydroxye-thyl methacrylate incorporated in DMF treated PET films by solvent-exchange technique, followed by treatment of films in e-lectrical discharges. Heparinization was accomplished by reacting glutaraldehyde with heparin and poly(2-hydroxyethyl methacrylate) present on the surface of modified polyester films. The immobilization of heparin was indirectly evidenced by chromatographying the silylated hydrolyza-tes of heparinized PET films and heparin, respectively. In vitro experiments demonstrated the enhanced thromboresistance of heparinized films. 

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