Oriented immobilization of antibodies and its applications in immunoassays and immunosensors

The immobilization of antibodies on solid-phase materials has been used in many areas such as purification, diagnostic immunoassays and immunosensors. Problems associated with the loss of biological activity of the antibodies upon immobilization have been noticed in many cases. One of the main reasons for such loss is attributed to the random orientation of the asymmetric macromolecules on support surfaces. In this paper, the approaches for achieving oriented coupling of antibodies to increase the antigen binding capacity are reviewed. Some issues such as steric hindrance caused by neighbouring antibody molecules, the distance between an antibody and the support surface and the use of antibody fragments are dealt with. Some applications of the oriented immobilized antibodies in immunoassays and immunosensors are examined.