Structure, Function, Orientation, Characterization and Immobilization of Antibodies for Immunosensor Development

Abstract

Immunosensors are a class of biosensing devices that use different bioreceptors such as antibodies, adhirons and aptamers. Antibodies are widely used key molecules for the detection of various analytes as they have a specific analyte binding site. According to recent research, the disulfide linkage located at the hinge region of an antibody can be used for generating half-antibody fragments. Other than this, the generated free-SH group can be used to offer oriented immobilization with the freely available antigen binding site that leads to an increase in accessibility for antigens and a decrease in variable interaction kinetics. Immunosensor capabilities i.e. selectivity and specificity, depend upon the orientation of antibodies and can be categorized based on the appropriate detection principle. These include surface modification with self-assembled monolayers, three-dimensional substrates and molecular imprinting, covalent binding (including targeting amine, carboxyl group, thiol coupling and carbodiimide linkage). Stability depends on bio affinity towards biotin–streptavidin interaction, material binding peptides, directed immobilization through DNA, protein binding peptides, metal affinity, and aptamers. Different transducing mechanisms are employed in the immunological development of biosensors; the preferred developments are based on optical and electrochemical immunosensing principles. In distinction to immunoassay, recent transducer technology allows the label-free quantification and detection of immune systems.