Enzyme-linked immunosorbent assay (ELISA) is a procedure of target antigen (or antibody) catch in samples with a particular antibody (or antigen), as well as goal molecule detection/quantitation working with an enzyme reaction using its substrate. In ELISA, many antigen-antibody mixes are used, consistently including an enzyme-labeled antigen or antibody, and enzyme activity is measured colorimetrically.
The enzyme activity is measured with a parasite that changes colour when altered by the enzyme. Light absorption of this product made after substrate addition is quantified and converted into numerical values. You can know more about high-quality ELISA mechanisms via https://www.bosterbio.com/protocol-and-troubleshooting/elisa-principle.
Based on the antigen-antibody mix, the assay is referred to as a direct ELISA, indirect ELISA, sandwich ELISA, competitive ELISA etc. ELISA is based on the notion of antigen reactions, representing the chemical interaction between electrons made by the B cells of both leukocytes and antigens. This particular immune response plays a significant function in protecting the body from germs such as toxins and pathogens.
Consequently, by harnessing this response, ELISA enables the sensitive and discerning quantitative/qualitative evaluation of antigens, such as proteins, peptides, nucleic acids, hormones, herbicides, and plant secondary metabolites. To detect such molecules, an antigen or antibody is tagged using enzymes, the so-called enzyme immunoassay, where alkaline phosphatase, horseradish peroxidase (HRP) and β-galactosidase are usually utilized.
The antigen from the liquid phase is immobilized on a solid phase, like a microtiter plate constituting stiff polystyrene, polyvinyl chloride, and polypropylene. Afterward, the antigen is permitted to respond with a particular antibody, which can be detected through an enzyme-labeled secondary antibody. The growth of color with a chromogenic substrate corresponds to the existence of the antigen.