Which among the following technology is based on the principle of antigen-antibody interaction ?

ELISA

ELISA (Enzyme-Linked Immunosorbent Assay) is based on the principle of antigen-antibody interaction.

ELISA is a highly sensitive technique used to detect the presence of specific antibodies or antigens in a sample. It relies on the specific binding between an antigen and an antibody, which forms the basis of its detection mechanism. In ELISA, an antigen or antibody of interest is immobilized on a surface. When a sample containing the corresponding antibody or antigen is introduced, if the target antigen or antibody is present, it will bind to the immobilized antigen or antibody on the surface. Then, a secondary enzyme-linked antibody is added, which binds to the antigen-antibody complex. This secondary antibody is tagged with an enzyme that produces a detectable signal (usually a color change) when a specific substrate is added, indicating the presence of the target antigen or antibody.

PCR (Polymerase Chain Reaction) and r-DNA (recombinant DNA) technology, on the other hand, do not primarily rely on the principle of antigen-antibody interaction. PCR is a method used to amplify specific DNA sequences, and r-DNA technology involves the manipulation and insertion of DNA sequences into other organisms. Both PCR and r-DNA technology are not specifically based on antigen-antibody interactions.