ABSTRACT
Immunosensors take advantage of the high selectivity provided by the molecular recognition of antibodies. The immuno-electrode responded to the corresponding saccharide in solution by a potential variation. M. Aizawa et al. reported two different types of immunosensors. The first was based on the measurement of the transmembrane potential across a membrane that incorporates an antibody. The other was designed on the basis of an enzyme-linked immunoassay. Immunosensors can be divided in principle into two categories: nonlabeled and labeled immunosensors. Nonlabeled immunosensors are designed so that the immunocomplex, that is, the antigen-antibody complex, is directly determined by measuring the physical changes induced by the formation of the complex. Nonlabeled immunosensors are based on several principles. Either the antibody or the antigen is immobilized on the solid matrix to form a sensing device. A sufficiently high selectivity may be obtained with nonlabeled immunosensors, although such problems as nonspecific adsorption onto the matrix-bound antibody surface remain unsolved.
