ELISA, also known as Enzyme-linked Immunosorbent Assay, is a type of immunoassay that is used to identify proteins, antibodies, and hormones. It is used to measure the level of a specific target in the samples like the serum, cell culture supernates, saliva, and urine. It is used as a diagnostic tool in the fields of biotechnology and medicine.
The conventional ELISA uses chromogenic reporters and substrates to produce color changes to indicate the presence of specific antigens in the sample. But, now new assay techniques use fluorogenic, electrochemiluminescent, and quantitative PCR reporters to create quantifiable signals. If you need high-quality ELISA kits to perform this, you can go to this site.
Advanced reporters help in measuring multiple antigens in a single or cycle of assays and higher sensitivities. Many antibodies are used to identify the substances in the target. Also, it is used to measure antigen and antibody concentration. ELISA has four types named as direct, indirect, sandwich, competitive.
The main step that is detecting the antigen can be accomplished by directly or indirectly absorption to the assay plate. In direct ELISA, an immobilized antigen is detected by a conjugated antibody that binds to the target enzyme. Only one antibody is used here. Indirect ELISA is similar to direct ELISA with an additional second step in which an enzyme-antibody is bound to the first antibody.
ELISAs are run in 96 microplates that are coated with a capture antibody specific for the antigen. Sandwich ELISA requires pairs of matching antibodies, where each antibody is specific for a different antigen-molecule. Competitive ELISA is a surface-based assay where the surface is coated with immobilized antibodies and reacts with the molecule of interest.