Immobilization electrostatic

Fiq. 60. Schematic illustrating electrostatic immobilization of DNA to a carboxyl-modified Si(lll) surface. Reproduced with permission from Ref. (194). Copyright 2000, American Chemical Society. 

Fig. 7.n SEM images of the 3D macroporous functionalized macroporous zeolitic membrane zeolitic membrane used as a support for enzyme bioreactor was prepared via the LbL electrostatic immobilization by the LbL procedure. Images assembly of PEs and enzyme (catalase) on the 3D (A-D) are cross-sections of the membrane at macroporous membrane. (Reprinted from [59] different magnifications. A biomacromolecule- with permission of Wiley-VCH). 

Zhujun Z., Seitz W.R., A fluorescent sensor for aluminum(III), magnesium(II), zinc(II) and cadmium(II) based on electrostatically immobilized quinolin-8-ol sulfonate. Anal. 

Depending on the size of the probe, either covalent (Figures 10 and 11) or electrostatic immobilization (Figure 12) may be preferred. In general, oligonucleotides and DNA fragments of approximately 20 to 70 bases are amino-modified and bound covalently to the chip surface. Complete or partially complementary DNA of up to 5000 nucleotide bases is bound to the chip by electrostatic adsorption. 

Z.Q. Feng, S. Imabayashi, T. Kakiuchi, and K. Niki, Electroreflectance spectroscopic study of the electron transfer rate of cytochrome c electrostatically immobilized on the w-carboxyl alkanethiol monolayer modified gold electrode. J. Electroanal. Chem. 394, 149-154 (1995). 

Figure 8. Examples of electrostatic immobilization of POMs (a) on the surface of (Si/A102)" particles [107] and (b) within nanocage of on MIL-101 coordination polymer [126].

Electrostatic immobilization is often employed when cDNA is used for array production, as this material, usually a product of the polymerase chain reaction (PCR), is available in relatively large amounts at low cost. 

Figure 5.23 Synthesis of borate-modified silica and subsequent electrostatic immobilization of the constrained-geometry titanium catalyst [104],...

Mayva K S ef a/1998 On the deposition of Langmuir-Blodgett films of Q-state CdS nanoparticles through electrostatic immobilization at the air-water interface Thin Solid Films Z 2 300... 

Franchina J. G., Lackowski W. M., Dermody D. L., Crooks R. M., Bergbreiter D. E., Sirkar K., Russell R. J., and Rishko M. V, Electrostatic immobilization of glucose oxidase in a weak acid, polyelectrolyte hyperbranched ultrathin film on gold Fabrication, characterization, and enzymatic activity, A a/. Chem., 71(15), 3133-3139,1999. 

The authors also describe the use of 96 in a fixed-bed, continuous-flow process. A mixture of Af-tosyl diallylamine in CH2CI2 was circulated through the catalyst bed at 40 C over a 5-h period, resulting in complete conversion to product however, after washing the catalyst bed and repeating the process a second time, the conversion was only 79%. A third recycle resulted in no product formation at all. This reveals that catalyst leaching and/or stability were a major problem under the reaction conditions, and that the electrostatic immobilization was largely ineffective for the described continuous-flow application. 

Bromothymol blue is an acidic pH chromoionophore where acid to base change corresponds to its neutral to anionic form, respectively. For this reason it can be electrostatically immobilized on the surface on anion-exchanger resin like Amberlite IRA 401. 

Electrostatic immobilization employs similar complementarity. The fiber surface can be coated with a thin polyelectrolyte membrane, which interacts electrostatically with oppositely charged sensing materials. For example, a negative surface, such as sulfonated polystyrene, can be prepared to efficiently immobilize a positively charged dye. Similarly, cationic polymers can bind various anions. Ionic indicators or biological molecules (i.e., either cations or anions) can be immobilized by electrostatic interaction. 

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