Linker chemistry

Flowever, the focus of the major part of the chapters lies on the couphng chemistry used for DNA immobilization. Successful immobihzation techniques for DNA appear to either involve a multi-site attachment of DNA (preferentially by electrochemical and/or physical adsorption) or a single-point attachment of DNA (mainly by surface activation and covalent immobihzation or (strept)avidin-biotin linkage). Immobilization methods described here comprise physical or electrochemical adsorption, cross-linking or entrapment in polymeric films, (strept)avidin-biotin complexation, a surface activation via self-assembled monolayers using thiol linker chemistry or silanization procedures, and finally covalent coupling strategies. 

The high purity (>95%) of the released product from resin 14 prompted us to investigate the potential of radical release as a traceless linker concept. To our knowledge, thermolytic radical fragmentation of covalent bonds is a mechanism of bond dissociation that has not been exploited so far for linker chemistry and for solid-phase transformations. Cleavage yields, determined by releasing nonvolatile products, were found to be higher than 90%. 

In 1996, Gauglitz and coworkers coated surfaces with various amino-and carboxy-substituted polymers [198], The polymers tested were branched poly-(ethyleneimine), a,co-amino-functionalized PEG, chitosan, poly(acrylamide-co-acrylic acid) and an amino-modified dextran. The amino-substituted polymers were immobilized on glass by first immobilizing an aminosilane, followed by succinic anhydride/A-hydroxysuccinimide linker chemistry. Poly(acrylamide-co-acrylic acid) was directly coupled to an aminosilanized surface. When probed with 1 mg mL 1 ovalbumin solution, nonspecific adsorption was lowest for the dextran derivative. Notably, nonspecific adsorption increased in most cases when a hydrophobic hapten (atrazine) was coupled to the polymer-modified surface. 

There are also a number of new dye-modified analogues for use in FRET analysis. A new four colour set of FRET dideoxy 5 -triphosphate terminators has been developed involving a rigid, linear ET cassette linker chemistry, and formulated with Thermo Sequenase II DNA polymerase. An alternative approach for a four colour set of FRET dyes has been reported where the dyes are incorporated into ODNs as phosphoramidite derivatives. ... 

Design of a ligand-drug conjugate linker chemistry... 

Fig. 7 Ellman s safety catch linker chemistry used for the synthesis of glycodendrons in a DNA synthesizer [85]...

Metal-Ion Cross-Linker Chemistry. The most commonly used metal-ion cross-linkers are titanates, zirconates, and borates. Titanate and zirconate gels display significantly different properties than borate gels, and these differences indicate the different nature of the cross-linking for the two types of ions. For example, gels produced by transition metal ions are more thermally stable than borate gels and do not recover viscosity after exposure to shear. 

Bradley A J, Murad K L, Regan K L, et al. (2002). Biophysical consequences of linker chemistry and polymer size on stealth erythrocytes Size dose matter. Biochim. Biophys. Acta. 1561 147-158. 

Abiotic linker chemistry Protease resistance Catalysis Alternative conformational profiles... 

The choice of a linker/anchor compound determines the fate of the peptide products. Stable amide/ester bonds such as with the Ala- Ala spacer Protocol 3) result in an array of immobilized peptides. Conventional linker chemistry can be incorporated to yield cleavable peptides in different formats. Esterification reactions are problematic in this open reactor system in such cases, a preformed amino add linker compound should be used. Such linkers should allow a solid phase bound deprotection/pre-purification followed by a mild final release reaction. Several options have been described (23-25). More sophisticated and superior amino membranes are now available from several sources (ABIMED, AIMS, Jerini, PerSeptive). 

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