Chapter 13 The immobilization of immunoreactants on solid phases

The simple manipulations required to separate free antibody or antigen from immune complexes immobilized non-covalently on plastic solid phase are probably the most important reason for the rapid increase in popularity of enzyme immunoassay techniques. The desired traits of the solid phase are (1) high capacity for binding immunoreactants (high surface/volume ratio), (2) the possibility of immobilization of many different immunoreactants, (3) minimal dissociation, (4) negligible denaturation of immobilized molecule, and (5) the orientation of immobilized antibody with binding sites toward the solution and the crystalline orientation function (Fc) to the solid phase. Thus, the chapter discusses the immobilization of immunoreactants on solid phases. It also describes the use of plastics as solid phases. The covalent attachment of antibodies or antigens to plastic is also highlighted. While covalent coupling is obligatory for the coating of solid phases other than plastics, it may also be advantageous for plastics. Some of the methods for the covalent linkage of proteins are quite undemanding and convenient for the large-scale preparation of immunoreactant-coated solid phases. Such methods are also necessary for the attachment of antigens that are poorly adsorbed on plastic, such as native DNA, small oligopeptides, and haptens.