Beads, immobilized

Yang, Q., Liu, X. Y., Umetani, K., Kamo, N. and Miyake, J. (1999). Partitioning of triphenylalkylphosphonium homologues in gel bead-immobilized liposomes chromatographic measurement of their membrane partition coefficients, Biochim. Biophys. Acta-Biomem., 1417, 122-130. 

The radioiodination procedure (see Note 9) described here uses IODO-BEADS, which contain the sodium salt of IV-chloro-benzenesulfonamide immobilized on nonporous, polystyrene beads. Immobilization of the oxidizing agent allows for easy separation of the latter from the reaction mixture. This method also prevents the use of reducing agents. 

The partition coefficients of triphenylalkylphosphonium homologs have been determined in gel bead-immobilized small or large unilamellar liposomes by chromatography [8]. It was claimed that the technique, immobilized liposome chromatography (ILC), is suitable for the determination of membrane partition coefficients of drugs. 

II.F.4 Binding on Silica Beads Immobilized Protein Fraction... 

The nucleic acid immobilization chemistry involved is detailed and presented together with the bead arraying or the bead immobilization systems, respectively. 

Another interesting bead immobilization technique is based on the entrapment of 1-100 pm-sized microspheres at an elastomer (PDMS polydimethyl siloxane)/air interface. Such a method enabled the immobilization of DNA bearing beads in an addressed manner (spotted) and with a high microsphere density, as can be seen in Fig. 3B. Compared to the methods presented above, this system permits the use of bead-assisted DNA immobilization with a large scale of bead coverage, since this chemical envelop is not used during bead immobilization. 

Ogbonna, J. C., Matsumura, M., and Kataoka, H. (1991) Production of glutamine by micro-gel bead-immobilized Corynebacterium glutamicum 9703-T cells in stirred tank reactor. Bioprocess Eng. 7, 11-18. 

Fig. 3.8 The gradient approach of Geissler et al.55 A PDMS stamp is used to ink a mixture of MHA (white) and ODT (black) onto a 2D array of silica beads immobilized on a gold substrate (1). Molecules are moving from the stamp to the gold surface with different speed (2). By reaching the gold, the molecules assemble into molecular rings whose composition creates a gradient from the inside to the outside (3)...

Laroche, C. and Gervais, R Unexpected thermal destruction of dried, glass bead-immobilized microorganisms as a function of water activity, Appl. Environ. 

Another unique silica-based approach to microscale DNA extraction currently underdevelopment utilizes a serpentine channel design, combined with an immobilized silica-bead solid phase and fluidic oscillation. This method, developed by Chung et al., relies on silica beads immobilized on the plasma-oxidized surface of the polymethylmethacrylate (PMMA) channels, instead of a packed-silica solid phase, as depicted in Figure 43.1c. Following bead immobilization, the solutions required for DNA binding, purification, and release are flowed back-and-forth through the device. This fluidic oscillation over the immobilized phase results in marked improvement of recovery and extraction efficiency over the same extraction methods with free beads. This method represents yet another variation of silica-based purifications that has been accomplished in microfluidic systems, exploiting previously optimized chemistries. In summary, the development of macroscale, commercial, silica SPE protocols has enabled the facile translation of DNA, and now RNA, extraction into microfluidic systems for a variety of applications. 

Alternatively, microchip technologies offer other platforms for HTS such as microarrays and microfluidic devices. Microarrays allow the simultaneous analysis of thousands of parameters within a single experiment and for this reason have become cracial tools in drug discovery and life sciences research. They consist of immobilized biomolecules spatially addressed on planar surfaces, microchannels or microweUs, or an array of beads immobilized with different biomolecules. Biomolecules commonly immobilized on microarrays include oligonucleotides, polymerase chain reaction (PCR) products, proteins, lipids, peptides, and carbohydrates. Currently, in situ synthesized microarrays can be purchased or... 

Staphylococcal enterotoxin B (SEB) is a potent bacterial protein toxin responsible for food poisoning, as well as a potential biological warfare agent. An afBnity probe has been prepared by inunobilizing anti-SEB antibody on the surface of paratol-uene-sulfonyl-functionalized magnetic beads. Immobilization and affinity capture procedures were optimized to maximize the density of anti-SEB IgG on the surface of magnetic beads and the amount of captured SEB. MALDI-MS detection of the emiched SEB from different matrices, such as cultivation media of S. aureus strains and raw milk samples (Schlosser et al. 2007). 

Reaction with glutaraldehyde-treated porous silica beads Immobilized on a particulate porous alumina... 

Because the presence of yeasts can represent a logistical bottleneck in postfermentation clarification, an alternative that has been studied is the use of immobilized microorganisms. Here, yeasts are trapped in calcium alginate beads or strands that are collectively packed into a synthetic mesh sleeve that is immersed into the juice/must. Relatively few yeasts (<10V mL) escape the encapsulation matrix (Yokotsuka et al., 1993) but yet conduct an active alcoholic fermentation. Yajima and Yokotsuka (2001) reported that concentrations of some undesirable volatile compounds (methanol, ethyl acetate, and acetaldehyde) were lower in wines made using Saccharomyces immobilized in double-layer beads. Immobilized yeasts... 

Figure 10.5 (a and b) Schematics of the intersectional view of microreaction chambers. Beads immobilizing enzymes were used as enzyme supporter in (a), and photoreactive polymer was used to immobilize enzymes in (b). (c) SEM image ofthe intersection ofthe... 

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