Non-covalent interaction-based immobilization

Since immunosensors usually measure the signals resulting from the specific immu-noreactions between the analytes and the antibodies or antigens immobilized, it is clear that the immobilization procedures of the antibodies (antigens) on the surfaces of base transducers should play an important role in the construction of immunosensors. Numerous immobilization procedures have been employed for diverse immunosensors, such as electrostatic adsorption, entrapment, cross-linking, and covalent bonding procedures. They may be appropriately divided into two kinds of non-covalent interaction-based and covalent interaction-based immobilization procedures. 

An adsorptive immobilization is a non-covalent coupling method on solid supports that is based on electrostatic, Van der Waals interactions, hydrogen bonds, and hydrophobic interactions of the reactants. 

This paper reviews the present status of affinity separation of cells based on the biospecific interaction of cellular receptors with proteinaceous ligands immobilized on a solid-phase matrix. Special emphasis was placed on the development of new matrix materials for immuno-affinity chromatography of lymphocyte subpopulations. Our newly developed matrix of poly(2-hydroxyethyl methacrylate)/polyamine graft copolymer offered novel advantages in (1) elimination of non-specific adsorption of lymphocytes and (2) simple immobilization procedure of ligand protein through non-covalent adsorption. This matrix allowed a rapid separation of preparative quantities of pure and vital lymphocyte subpopulations (IgG-positive and -negative cells) in excellent yield. 

Proteins non-covalently adsorbed or covalently linked on solid-phase matrices have many applications in the wide area of science and technology (1 2). Indeed, in the field of separations science and technology, affinity selection based on the biospecific interaction of biomolecules with proteinaceous ligands immobilized on a solid-phase matrix has been widely noted as the separation method with highest selectivity, and is commonly utilized for separation and purification of biopolymers including proteins and nucleic acids (3,4). ... 

The use of hydrophobic interactions for the non-covalent immobilization of catalysts is another possible concept for attachment of catalysts. The concept is based on hydrophobic interactions between commercially available reversed-phase silica gel and a hydrophobic anchor attached to catalysts. 

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