Surface Chemistries
ICx Nomadics Recommendation for Kinetic Analysis Applications - We recommend two dimensional surface chemistry for kinetic applications as the interpretation of kinetic constants is simplified.
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Gold Only Surface
Sensor provided with gold coated glass surface with no further modification to facilitate the attachment of user-developed functional chemistry.
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COOH1
The COOH1 surface is a two dimensional carboxylated coating suitable for a wide variety of biomolecular interactions. This surface has proven to resist non-specific binding better than any other coating by taking advantage of the chemical properties of polyethylene glycol (PEG). Coupling of ligands to this surface is normally achieved via amine coupling (EDC/NHS chemistry) but alternative methods such as thiol coupling, disulfide exchange and hydrazide coupling may also be employed.
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COOH2
The COOH2 surface is a short carboxylated polysaccaride coating suitable for a wide variety of biomolecular interactions. This surface is similar to COOH1 in charge potential but is more favorable in some applications as polysaccaride has different characteristics. The same coupling chemistries can be used with the COOH2 surface as with COOH1 surface.
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COOH 5
The COOH5 surface is a hydrogel-based sensing surface that enables higher ligand capacity. It is composed of a biocompatible hydrophilic polysaccharide in a three-dimensional matrix. Carboxyl groups naturally present on the polysaccharide allow for ligands to be covalently linked via amine containing groups utilizing coupling techniques similar to those of the COOH1 surface. Ligands can be coupled in excess of 20kRU’s allowing binding interactions to be observed for small molecules and for ligands that exhibit low binding activity.
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BioCap
The BioCap surface is a two dimensional coating that utilizes the high affinity biotin – avidin interaction as the basis for ligand immobilization. A deglycosylated variant of avidin is covalently coupled to the BioCap surface; making it ideal for the capture of biotinylated reagents including peptides, oligonucleotides, proteins and sugars in a non-reversible manner.
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VesCap
The VesCap surface is a two dimensional chemistry for the immobilization of vesicles. Liposomes, unilamellar vesicles and even crude membrane preparations may be conveniently immobilized in a single step. A hydrocarbon chain is presented on this surface as an ‘anchor’ to hold the hydrophobic portion of the membrane to the surface. Components embedded in the vesicles will continue to diffuse and this property makes this surface ideal for membrane bound receptor studies.
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HisCap
The HisCap surface is a two dimensional chemistry for the reversible immobilization of His-tagged ligands. This surface is ideal for capture of polyhistidine-tagged recombinant proteins. Immobilized proteins may be removed by exposure to free imidazole allowing the surface to be re-coated and reused.
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HiCap
The HiCap surface is a three dimensional polysaccaride chemistry that is ideal for amine coupling of small peptides, drugs and other small molecules that possess amine groups. Such biomolecules show negligible preconcentration and must be exposed to the surface at high concentrations. This surface is uncharged and confers high resistance to non-specific binding. Very high binding capacities may be achieved using standard coupling chemistries such as CDI.
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AvHiCap
The AvHiCap surface is a three dimensional polysaccaride coating utilizing biotin to capture avidin-conjugated ligands. It is non-charged thereby limiting non-specific binding and making this surface ideal for acidic proteins. This surface consists of a large polysaccaride hydrogel and is useful where high binding capacity is required.
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AvCap
The AvCap surface is a two dimensional coating utilizing biotin to capture avidin-conjugated ligands. It can reversibly bind a full monolayer of protein via the strong affinity that exists between biotin and the four binding sites of avidin, streptavidin and their derivatives. Avidin bound to a planar layer of biotin can be used to capture another biotinylated ligand using one of the other available sites. A solution of guanidine-HCl may be used to denature the protein leaving the surface-bound biotin residues free to recapture fresh conjugates.
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COOH 3
The COOH3 surface is identical to the COOH1 surface but is engineered to possess a far lower density of carboxylic acid groups. This lower capacity surface is tailored for kinetic applications where low binding capacity is required, but its greatest strength is in the reduced non-specific binding that results from the reduced electrostatic potential.