Bifunctional linkers

Immobilization of these clusters on Pt(hkl) surfaces, employing bifunctional linkers with one pyridyl- and one thiol-based anchoring group, was achieved [334, 335]. The terminal pyridyl anchor ensures a strong chemical bond to the... 

It is also worthwhile to outline at this place the immobilization procedure that was used for the preparation of type I CSPs A bifunctional linker with a terminal isocyanate on one side and a triethoxysilyl group on the other end (3-isocyanatopropyl triethoxysilane) was reacted with the native cinchona alkaloids quinine and quinidine and subsequently the resultant carbamate derivative in a second step with silica [30], Remaining silanols have been capped with silane reagents, yet, are less detrimental for acidic solutes because of the repulsive nature of such electrostatic interactions. CSPs prepared in such a way lack the hydrophobic basic layer of the thiol-silica-based CSPs mentioned earlier, which may be advantageous for the separation of certain analytes. 

Bifunctional linkers bearing functional groups like thiols, disulfides or phosphines are widely used for covalent binding between Au NPs and biomolecules. For example, Au NPs stabilized with a functionalized polysiloxane shell have been used for covalent binding to biomolecules [152]. 

Ringsdorf and coworkers used monolayer techniques for the creation of lipid functionalized streptavidin layers.252,253 In their pioneering work, a monolayer of biotinylated phospholipids initially created a two-dimensional docking matrix for the immobilization of streptavidin. In an effort to further expand this system while maintaining control over its structure, bis-biotinylated bifunctional linkers were employed. Addition of these linkers to concanavalin A created a new protein-based bidentate linker. Upon addition to the monolayer of the lipid-functionalized streptavidin a second biotilynated protein layer was created. Upon the further addition of streptavidin, they achieved in a step-by-step construction process well-defined alternating protein triple layers of streptavidin and concanavalin A (Figure 7.37b). A similar approach has more recently been used to crosslink... 

Our group has developed a method based on the immobilization of one reaction partner and each library member, the potential catalyst, on the same bead [20], This can easily be accomplished by means of a bifunctional linker that carries on one end the reactant A and on the other end the library member (Figure 5.4.7). If the reaction partner B is labeled with, e.g., a dye, a fluorophore, or radioactivity a reaction between A and B leads to the covalent attachment of the marker to those beads that carry catalytically active library members. These beads are then readily detected with a low-power microscope. 

FIGURE 7.4 Automated synthesis utilizing the bifunctional linker gives access to ready-to-use oligosaccharide constructs that are useful for various biomedical applications. 

Organic ligands added to sol solutions can be used to control NC growth and size dispersities. " This approach, analogous to the method described for metal NCs in Section 2.1, employs bifunctional linkers to tether metal salts to the sol-gel network to improve the homogeneity of the sample. Silica precursors mixed with 3-aminopropyltriethoxysilane (APTES) and cadmium nitrate were allowed to gel. Following oxidative treatments, the resulting CdO particles were converted to CdS upon exposure to H2S, as shown in equation (4). The size distribution of particles was much narrower under these conditions than when APTES was omitted from the reaction. 

Figure 13. (a) Formation of mixed SAM on Au electrode, (b) immobilization of Fc-D, (c) immobilization of thiolated capture probe with bifunctional linker (succinimidyl 4-(/V-maleimidomethyl)cyclohexane-l-carboxylate (SMCC)), (d) hybridization with target, (e) hybridization with biotinylated detection probe, (f) association with avidin-alkaline phosphatase, (g) description of the process of the electrocatalytic reaction of />-aminophenol (p-AP) via electronic mediation of ferrocenyl dendrimer (Adapted from Ref. [160])... 

The extracted GSLs were briefly treated by ozone and heated in neutral buffer to release free-reducing glycans that can be permethylated for MS analysis or conjugated to a bifunctional linker for HPLC separation and microarray study. Like other methods based on (1-elimination, this method is also not suitable for sphinganine and phytosphingosine GSLs that lack the C=C bond. 

TABLE 1 Comparison of Three Bifunctional Linkers Used for Microarray Preparation ... 

Kris, R.M. Eelder, S. High Throughput Assay System Using Multi Array Plate Screen, Nuclease Protection, Oligonucleotide Anchors, Bifunctional Linkers, and Mass Spectrometry, PCT Int. Appl. (2000), 111 pp., WO 0037684 Al 20000629. 

Gemtuzumab ozogamicin is a humanized lgG4, kappa antibody conjugated with a cytotoxic antitumor or antibiotic, calicheamicin via a bifunctional linker. It has a MW of 151-153 kDa. 

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