Description
Hydrogel surfaces, particularly carboxymethyl dextran hydrogels, offer many advantages when used as a SPR sensor chip surface. Carboxymethyl dextran surfaces are very stable and resistant to non-specific binding of biomolecules. The dextran layer is in the form of a highly flexible non-cross-linked brush-like structure extending 100 to 200 nanometers from the surface. The flexible nature of the dextran contributes to the accessibility of binding sites on an immobilized ligand. Biomolecules are easily coupled to the surface using a variety of techniques similar to those used in affinity chromatography. Large amounts of protein, up to 50 ng/mm3, can be immobilized on carboxymethyl hydrogel surfaces due to the 3-dimensional nature of the hydrogel layer. This is important for experiments where a low molecular weight analyte binds to a surface immobilized protein.