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What are the commonly used chemiluminescence immunoassays?
2019-03-21
来源：亚科官网
Chemiluminescent Labeling Immunoassay, also known as chemiluminescence immunoassay (CLIA), is an immunoassay instrument that directly labels antigens or antibodies with chemiluminescent agents. The chemiluminescence immunoassay analyzer consists of two parts, an immunoreactive system and a chemiluminescence analysis system. The chemiluminescence analysis system utilizes the catalysis of a chemiluminescent substance and the oxidation of an oxidant to form an excited state intermediate. When the excited state intermediate returns to a stable ground state, the photon (hM) is simultaneously emitted, and the luminescence is utilized. A signal measuring instrument measures the quantum yield of light. The immunoreactive system directly labels a luminescent substance (which generates an excited state intermediate under the excitation of a reactant) on an antigen (chemiluminescence immunoassay) or an antibody (immunochemiluminescence analysis), or an enzyme acts on a luminescent substrate.
1. Direct chemiluminescence immunoassay
An immunoassay method for directly labeling an antigen or antibody with a chemiluminescent agent. The commonly used chemiluminescent substance is an acridine ester compound acridinium ester (AE), which is an effective luminescent label which emits light by the action of a luminescent reagent (NaOH-H2O2), which strongly emits light in one second, glowing for fast flashing. Acridinium ester is used as a marker for immunoassay. Its chemical reaction is simple, rapid and requires no catalyst. The detection of small molecule antigens is based on competition method, the macromolecular antigen is sandwiched, the non-specific binding is low, and the background is low. The combination does not reduce the amount of light produced, thereby increasing sensitivity.
2. Chemiluminescent enzyme immunoassay
From the point of view of marker immunoassay, chemiluminescent enzyme immunoassay (CLEIA) should be an enzyme immunoassay, but the substrate of the enzyme reaction is a luminescent agent, and the procedure is identical to the enzyme-free analysis: labeling the biologically active substance with an enzyme, an immunological reaction is carried out (such as an enzyme-labeled antigen or antibody), and the enzyme on the immunoreactive complex acts on the luminescent substrate, emits light under the action of a signal reagent, and performs luminescence measurement using a luminescence signal meter. The currently used labeling enzymes are horseradish peroxidase (HRP) and alkaline phosphatase (ALP), which have their own luminescent substrates.
1) Horseradish peroxidase-labeled chemiluminescent enzyme immunoassay
The analysis system uses a horseradish peroxidase (HRP)-labeled antibody (or antigen) to form a solid phase baby antibody-test antigen-enzyme (HRP) after immunological reaction with the sample to be tested and the solid phase carrier in the reaction system. The antibody complex is labeled, followed by the addition of a luminol illuminant, H2O2, and a chemiluminescence enhancer to produce chemiluminescence.
2) Alkaline phosphatase-labeled chemiluminescent enzyme immunoassay
The alkaline phosphatase-labeled chemiluminescent enzyme immunoassay system uses an alkaline phosphatase-labeled antibody (or antigen) to form an immunophase baby antibody-test antigen after immunological reaction with the sample to be tested and the solid phase carrier in the reaction system. Enzyme (alkaline phosphatase)-labeled antibody complex, followed by the addition of an AMPPD illuminant, which cleaves the AMPPD by deactivating the phosphate group.
3. Electrochemiluminescence immunoassay
Electrochemiluminescence immunoassay is an electrochemiluminescent luminescent agent, a pyridinium-labeled antibody (antigen), with tripropylamine (TPA) as an electron donor, and a specific chemiluminescence reaction occurs in an electric field due to electron transfer, which includes electrochemistry and chemiluminescence two processes.
In the electrochemiluminescence immunoassay system, the magnetic microparticles are coated with an antibody (antigen) by a solid phase carrier, and the antibody (antigen) is labeled with a pyridinium, and the sample to be tested is immunoreacted with the corresponding antigen (antibody) in the reaction system. The magnetic microparticle-coated antibody-anti-antigen-tripyridinium-labeled antibody complex is formed, and the above complex is inhaled into the flow chamber while introducing TPA buffer. When the magnetic particles flow through the surface of the electrode, they are attracted by the electromagnet mounted under the click, and the unbound antibody and the specimen are washed away by the buffer, and at the same time the electrode is pressurized, and the electrochemiluminescence reaction is initiated to make the terpyridine. And TPA electron transfer on the surface of the electrode to produce electrochemiluminescence.
Related links: Classification and application of chemiluminescence immunoassay
Edited by Suzhou Yacoo Science Co., Ltd.
