Polymer surface immobilization

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. 

With further understanding how molecular rotors interact with their environment and with application-specific chemical modifications, a more widespread use of molecular rotors in biological and chemical studies can be expected. Ratiometric dyes and lifetime imaging will enable accurate viscosity measurements in cells where concentration gradients exist. The examination of polymerization dynamics benefits from the use of molecular rotors because of their real-time response rates. Presently, the reaction may force the reporters into specific areas of the polymer matrix, for example, into water pockets, but targeted molecular rotors that integrate with the matrix could prevent this behavior. With their relationship to free volume, the field of fluid dynamics can benefit from molecular rotors, because the applicability of viscosity models (DSE, Gierer-Wirtz, free volume, and WLF models) can be elucidated. Lastly, an important field of development is the surface-immobilization of molecular rotors, which promises new solid-state sensors for microviscosity [145]. 

Choi J, Konno T, Matsuno R et al (2008) Surface immobilization of biocompatible phospholipid polymer multilayered hydrogel on titanium alloy. Colloids Surf B Biointerfaces 67 216-223... 

Kumar, P., Agarwal, S.K., and Gupta, K.C. (2004) N-(3-Trifluoroethanesulfonyloxypropyl)-anthraqui-none-2-carboxamide a new heterobifunctional reagent for immobilization of biomolecules on a variety of polymer surfaces. Bioconjugate Chem. 15, 7-11. 

Yan, M., Cai, S.X., Wybourne, M.N., and Keana, J.F.W. (1994) N-Hydroxysuccinimide ester functionalized perfluorophenyl azides as novel photoactivatable heterobifunctional cross-linking reagents. The covalent immobilization of biomolecules to polymer surfaces. Bioconjugate Chem. 5, 151-157. 

Amorphous Systems (Polymer and Surface Immobilized Catalysts and Inorganic Glasses)... 

Both the approaches discussed above are addressed to the desire for immobilization of the metal species, while the corrosive and volatile promoter must still be trapped and recycled. Recently, Webber et al. (28) have attempted to achieve immobilization of both the metal species and the promoter by attaching rhodium to a polymer functionalized with chlorinated thiophenol groups. This imaginative approach is presently plagued by both low reactivity and rhodium loss from the polymer surface. 

An alternative containment scheme is immobilization of active species on a surface" " or within a tethered polymer brush or network. ° Surface immobilization can achieve high surface utilization by locating mediators and biocatalysts within nanometers of conducting surfaces. Immobilization on polymer networks allows for dense packing of enzymes within electrode volumes at the expense of long-distance electron mediation between the enzyme active center and a conductive surface. Such mediation often represents the rate-limiting step in the overall electrode reaction. 

Zhao B, Brittain WJ (2000) Polymer brushes surface-immobilized macromolecules. Prog Polym Sci 25 677-710... 

Reservoir capacity is the ability of a polymer to hold solutes within its matrix. BiocompatibiUty is the relationship of a polymer surface with biological materials, specifically living cells. Ligand attachment is the technique of attaching active side chains to the backbone of a polymer. The most interesting example is the covalent immobilization of enzymes without deactivation. 

Integration of MIPs with the transducer surface (immobilization) is a foremost and arduous step of chemosensor fabrication. The polymer material must perfectly adhere to this surface, neither dispersing away nor peeling off in aggressive solvent solutions, under extreme pH or ionic strength conditions, or under analytical flow conditions. A range of methods is being used for immobilization of imprinted... 

Surface-functionalized polymers are also of interest for uses in biochemical reactors, and biomedical sensors. The immobilization of enzymes on a polymer surface is an important example. Numerous reasons exist for attempting to immobilize enzymes on the surfaces of polymers. For one thing, immobilization often enhances the length of time over which the protein maintains its catalytic activity, compared to the same... 

Fig. 17. Collagen immobilization onto the PAAc-grafted polymer surface with the use of carbodiimide...

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