Immobilization and Interaction of Biomolecules at the Solid-Liquid Interface : Applications to Solid-Phase Analytical Techniques

Abstract: The development of solid-phase-analytical techniques based on surface-concentration-measuring devices requires a stable and reproducible immobilization of biomolecules on well-characterized solid surfaces. This study reports on the immobilization of Immunoglobulin G, Protein A and Fibronectin on chemically modified silica surfaces. Reactive groups were introduced to the silica surfaces by chemical-vapour deposition of silane. The silanized surfaces were characterized by ellipsometry, contact angle measurements and scanning electron microscopy, which revealed smooth, stable and reproducible silane films of monolayer character. Immobilization by adsorption as well as covalent immobilization by the use of thiol-disulphide exchange reactions, thereby controlling the maximum number of covalent bonds to the surface, were studied. The immobilization was quantitated in a study applying both ellipsometry and radiotracer techniques. The amounts of immobilized proteins obtained from the radiolabeling experiments agreed well with those calculated from ellipsometric data. The results outline the possibilities of obtaining a controlled covalent binding of biomolecules to solid surfaces with an optimal stability and biological activity of the immobilized molecules.