ELISA - ELISA assay technology has been used for decades as a reliable method of detecting and quantitating proteins, antibodies and other biomolecules by using an antibody-antigen reaction. An enzyme-linked immunosorbent assay (ELISA) is one of the simplest, most sensitive and versatile immunoassays. ELISAs are commonly used as diagnostic tools in medicine as well as for screening and quality control/quality assurance testing in many industries
ELISA is a fast, effective and inexpensive way to screen samples for the presence of antibodies or antigens. The method uses a capture antibody that binds to the target antigen, and an enzyme conjugated with an antibody that binds to the capture antibody in order to detect it. Generally speaking, ELISA is used to detect a wide range of compounds including proteins, peptides, hormones and enzymes.
ELISA is a technique that detects and quantitates antigen-specific antibodies in serum. ELISA stands for enzyme-linked immunosorbent assay, which refers to the use of an enzyme (horseradish peroxidase or alkaline phosphatase) coupled with an antibody to detect a specific antigen.
The ELISA is one of the simplest, most sensitive and versatile immunoassays. It involves three major steps:
ELISAs are commonly used as diagnostic tools in medicine as well as for screening and quality control/quality assurance testing in many industries. An ELISA is a fast, effective, and inexpensive way to screen samples for the presence of specific antibodies or antigens. The enzyme-linked immunosorbent assay (ELISA) is a technique that detects and quantitates antigen-specific antibodies in serum. To accomplish this goal, a conjugate must be formed between an antibody (or antigen) with a carrier protein (such as bovine serum albumin or Tween 20). After incubation with the test sample, it's washed to remove any non-specifically bound material; then the conjugates will bind to any remaining analyte in solution through their specific binding sites on either end of their attached antibodies. The final step involves treating this mixture with an enzyme substrate (such as 3,3',5,5'-Tetramethylbenzidine) that produces colored products when it reacts with peroxidase enzymes present on both sides of the ELISA plate (one side for each conjugate). This allows us to determine how much analyte we have present by measuring how much color there is on each spot where one should be present!
During an ELISA, an antigen must first be immobilized to a solid surface such as a microtiter plate well. There are many ways that this can be accomplished. One method is through covalent bonds, which are molecules that link together and form chemical bonds between the surface of the well and the antigen. Another method is through non-covalent interactions between the antigen and its binding partners on the well surface.
Antibodies are special proteins that bind to a particular antigen, or target. Antigens are molecules on the surface of bacteria, viruses and other microorganisms that can trigger an immune response in humans. The antibody is selected to match the type of antigen present in your sample. When added to your sample containing the antigen, it binds tightly and remains bound if present in high concentrations. The addition of a second reagent called a substrate results in production of colored product that can be read by eye or by instrumentation such as a fluorometer (it looks like an audio speaker).
ELISA is an immunoassay that uses antibodies to detect and quantify proteins (antigens) in a sample. ELISA is based on the principle of competitive binding. An antibody, specific for the antigen to be detected, is coated onto a solid phase (typically a microtiter plate), along with the antigen of interest; then the sample containing the protein being tested is added. If there are any proteins present in the sample, they compete with labeled antibodies for binding sites on the antigen; since each well has only one type of label, this competition can be judged by comparing absorbance at 405nm after incubation for varying times.
In contrast to other immunological techniques ELISA does not require radiolabels or fluorescent dyes for detection and quantitation, which reduces risks associated with exposure to radioactivity or hazardous chemicals/waste disposal issues. ELISA is a fast, effective and inexpensive way to screen samples for the presence of specific antibodies or antigens. ELISA is one of the simplest, most sensitive and versatile immunoassays
ELISAs are a powerful tool for detecting and quantifying antigens. ELISA is one of the most sensitive immunoassays available today and therefore has been adopted as the standard method for many different types of assays, including diagnostic testing. ELISA can be used to detect antigens in serum or other body fluids, but also in tissue homogenates or culture supernatants from bacterial cultures.