ELISA, which stands for Enzyme-Linked Immunosorbent Assay, is a biochemical technique used to detect and measure the presence of specific proteins or antibodies in a sample. It is a widely used diagnostic test that can be performed on various samples, such as blood, urine, saliva, and even food samples. The ELISA technique can detect and quantify small amounts of proteins, making it a highly sensitive and specific tool in the field of medical diagnosis and research.
The ELISA technique works by using an enzyme-linked antibody to detect the presence of a specific antigen or antibody in a sample. The sample is first added to a well on a plate that has been coated with a specific antigen or antibody. If the antigen or antibody is present in the sample, it will bind to the coated antigen or antibody on the plate. Any unbound components of the sample are then washed away.
Next, a secondary antibody that is linked to an enzyme, such as horseradish peroxidase or alkaline phosphatase, is added to the well. This antibody will bind to any antigen-antibody complex that has formed on the plate. After another washing step, a substrate solution is added to the well. If the enzyme-linked antibody has bound to the antigen-antibody complex, it will react with the substrate, resulting in a color change that can be measured by a spectrophotometer.
The amount of color change is proportional to the amount of antigen or antibody present in the sample. Therefore, by comparing the amount of color change to a standard curve, the concentration of the antigen or antibody in the sample can be determined.
ELISA has a wide range of applications in medicine, such as the detection of HIV, hepatitis, and various types of cancer. It is also used in food science to detect the presence of allergens and pathogens in food samples. The ELISA technique has the advantages of being highly sensitive, specific, and relatively easy to perform, making it a valuable tool in many areas of research and diagnostics.
