Immobilization polyvinyl alcohol

J. Xu et al. [283] have shown that immobilization of enzymes can be done using a specially designed composite membrane with a porous hydrophobic layer and a hydrophilic ultrafiltration layer. A polytetrafluoroethylene (PTFE) membrane with micrometer pores as an excellent hydrophobic support for immobilization was employed for the porous hydrophobic layer, and a biocompatible material of polyvinyl alcohol (PVA) which provided a favourable environment to retain the lipase activity was used to prepare the hydrophilic... 

The first section, Chemical Reactions on Polymers, deals with aspects of chemical reactions occurring on polymers—aspects relating to polymer size, shape, and composition are described in detail. One of the timely fields of applications comprises the use of modified polymers as catalysts (such as the immobilization of centers for homogeneous catalysis). This topic is considered in detail in Chapters 2, 3, 8, 9, and 11 and dealt with to a lesser extent in other chapters. The use of models and neighboring group effect(s) is described in detail. The modification of polymers for chemical and physical change is also described in detail in Chapters 2 (polystyrene) 4 (polyvinyl chloride) 5 (polyacrylic acid, polyvinyl alcohol, polyethyleneimine, and polyacrylamide) 6 (polyimides) 7 (polyvinyl alcohol) 8 (polystyrene sulfonate and polyvinylphosphonate) 10 (polyacrylamide) and 12 (organotin carboxylates). 

Mass transfer rates for skirted bubbles in polyvinyl alcohol solutions have been measured by Guthrie and Bradshaw (G9) and Davenport et al (D4). When a skirt is present the transfer rate increases, but not in proportion to the increase in surface area. Davenport attributes this to the accumulation on the surface of the skirt of surface-active impurities which immobilize the interface and reduce the transfer rate. Presumably transfer rates from skirted bubbles or drops in very pure liquids would be appreciably higher than from fluid particles without skirts. 

Work at the EPA Gulf Breeze Laboratory has demonstrated the potential usefulness of encapsulation in the bioremediation of PAHs. A model system has been developed in which a pure culture capable of degrading fluoranthene (strain EPA505) has been successfully encapsulated in polyurethane foam and polyvinyl alcohol (Baker et al., 1988). The capsules can be stored for several months at 4 °C with only minimal loss of viability. Upon addition of the capsules to moist soil, fluoranthene mineralization commenced in approximately the same way as observed when fresh bacterial cells were added to the soil. These results are shown in Figure 5.7a. Since the same inoculation size was used in all flasks during this experiment, the results suggest that the immobilization process does not significantly affect microbial activity. 

Ester Synthesis Catalyzed by Mucor miehei Lipase Immobilized on Magnetic Polysiloxane-Polyvinyl Alcohol Particles... 

Acetylcholineesterase and choline oxidase Co-immobilized enzyme (AChE and ChO) on 7 pm diameter carbon-fiber electrode entrapped with polyvinyl alcohol quaternized stil-bazole. Sensor was used as an amperometric detector for ACh. Linear response in the range 0.1-1 mM of ACh. Response time was 5 s. [83]... 

Immobilized HRP on gemini surfactant-polyvinyl alcohol composite film The immobilized HRP presented good bioelectrocatalytic activity to the reduction of H202, N02 , 02, and trichloroacetic acid. For H202 the catalytic current was linear to its concentration (0.195-97.5 M) [45]... 

Liu L, Zhao F, Liu L et al (2009) Improved direct electron transfer and electrocatalytic activity of horseradish peroxidase immobilized on gemini surfactant-polyvinyl alcohol composite film. Colloid Surf B Biointerf 68 93-97... 

Higher hydrolytic stability is exhibited by capillaries based on vinyl coatings as primary anchor group, where, in the second step, vinyl acetate is polymerized and subsequently hydrolyzed with sodium methylate in methanol [6]. Such capillaries are stable up to a pH value of 10. Polyvinyl alcohol has also been thermally immobilized onto the capillary surface [7]. With such stable layers in the acidic and neutral region no measurable EOF is present and the stability of the capillaries is very good. 

Bulmus et al. (1997) demonstrated the modified PMMA mono-size microbeads for glucose oxidase immobilization, in which PMMA substrate was washed with 10% (w/v) NaOH followed by 50% (v/v) ethanol. Freshly cleaned PMMA was then immersed in a solution of 1 g/L polyvinyl alcohol for 20 min, followed by oxidation reaction with a solution of 1% NaI04 for 1 h at room temperature. The amino functionality was then added by using a solution of 10% (w/v) hexamethylene diamine in 100 mM borate buffer pH 11.5, for 2 h (123) (shown in scheme 8.5). 

Quinoprotein glucose dehydrogenase and recombinant tyrosinase from Streptomyces antibioticus were immobilized on polyvinyl alcohol and coupled to a Clark oxygen electrode. LOD was 5 nM for dopamine (10a), L-dopa (10b) and adrenaline (epinefrine, 15a). An electroimmunological biosensor for p-cresol was developed, based on the... 

Tungstophosphoric acid immobilized in polyvinyl alcohol hydrogel beads as heterogeneous catalyst... 

Entrapment has been applied primarily to biomolecules for biosensor fabrication (table 8.3). Essentially, the molecule to be immobilized is formulated with the components of a membrane or film prior to laying down the membrane or film, or is added after the membrane or film is in place on the transducer. In the latter case, the molecule to be entrapped diffuses into the membrane or film. Typical films/matrices used for entrapment include starch, polyacrylamide, silicone rubber, polyvinyl alcohol, and polyvinyl chloride. 

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