Chemiluminescence immunoassay combines the high sensitivity of chemiluminescence and the high specificity of immunoassay. It has been widely used in clinical testing, drug analysis, environmental monitoring and other fields.
Chemiluminescence immunoassay (CLIA) is a type of immunoassay method that directly label antigens or antibodies with chemiluminescence agents. Acridine esters are ideal luminescent substrates, which can be oxidized by hydrogen peroxide to emit light in an alkaline environment.
Chemiluminescence Enzyme Immunoassay (CLEIA) is an enzyme-labeled immunoassay that uses chemiluminescence agents as substrates for enzyme reactions. After two-stage amplification of enzyme and luminescence, it has high sensitivity. Peroxidase is used as a labeling enzyme, luminol is used as a luminescent substrate, and a luminescence enhancer is added to improve sensitivity and luminescence stability. The applied labeling enzyme can also be alkaline phosphatase, the luminescent substrate is dioxetane phosphate, and the solid phase carrier is magnetic particles.
The immunoassay technology has two methods: one is the determination of small molecule antigenic substances by the competition method; the other is the measurement of antigenic substances of large molecules by the double antibody sandwich method.
The solid-phase magnetic powder particles used in this instrument are extremely small, with a diameter of only 1.0 μm. This greatly increases the coating surface area, increases the amount of antigen or antibody adsorption, speeds up the reaction, and makes cleaning and separation easier.
(1) Competitive reaction: Use an excess of antibody coated with magnetic particles, and add the antigen to be tested and the quantitative labeled acridinium ester antigen to the reaction cup for incubation. There are two types of binding of the immune response. One is to bind the labeled antigen and antibody to form a complex, and the other is to determine the binding of antigen and antibody.
(2) Double-antibody sandwich method: The labeled antibody and the test antigen are combined with the coating antibody to form a reaction form, that is, a complex of the coating antibody-determining antigen-luminescent antibody.
Electrochemiluminescence immunoassay (ECLI) is a specific luminescence reaction initiated by electrochemistry on the electrode surface, including electrochemistry and chemiluminescence. The label used in the analysis is the electrochemiluminescence substrate ruthenium terpyridine or its derivative N-hydroxysuccinamide (NHS) ester, which can be combined with antibodies or antigen molecules of different chemical structures through chemical reactions to produce labeled antibodies or antigens .
These four types have their own advantages and disadvantages. Regardless of which chemiluminescence principle is used, attention should be paid to selecting core materials, eliminating anti-interference factors, eliminating hook effects to the greatest extent and reducing instrument failure rate. In addition, if you have any questions or needs about the immunoassay analyzer, please feel free to consult Well Biotech Company.