Enzyme-linked immunosorbent assay (ELISA) is a sensitive and commonly used laboratory technique employed to detect and measure the presence and concentration of specific proteins or antibodies in biological samples, such as blood or urine. It relies on the principle of antigen-antibody interaction to facilitate the detection of target molecules.
ELISA is performed by first coating a solid surface, such as a microplate or test tube, with a known antigen or capture antibody. The sample containing the target protein or antibody is then added to the coated surface and allowed to interact. If the target is present, it will bind specifically to the capture antibody or antigen immobilized on the surface.
The next step involves the addition of a detection antibody. This antibody is labeled with an enzyme, such as horseradish peroxidase or alkaline phosphatase, which can produce a colorimetric or fluorescent signal indicative of the presence of the target molecule.
After a specific incubation period, the excess antibodies and sample components are removed by multiple washes. Finally, a substrate that reacts with the enzyme label is added, resulting in a color change or the production of light. The intensity of the signal generated is directly proportional to the concentration of the target molecule in the original sample.
ELISAs are widely utilized in various fields, including immunology, clinical diagnostics, and pharmaceutical research. They offer high sensitivity, specificity, and scalability, enabling the detection and quantification of low-level analytes. These assays are valuable tools for disease diagnosis, monitoring the effectiveness of treatments, detecting antibodies in autoimmune disorders, screening for infectious agents, and evaluating the production of specific proteins in research settings.
