Luminescence immunotechnology is a method that combines luminescence and immune responses to detect antigens or antibodies. It uses micro-multiplication technology with good sensitivity and specificity; the detection range is very wide, from traditional proteins, hormones, enzymes to drugs can be detected. Clinical applications are mostly automatic chemiluminescence immunoassay analyzer, automatic microparticle chemiluminescence immunoassay analyzer and automatic electrochemiluminescence immunoassay analyzer.
Chemiluminescence immunoassay technology is also called micro-multiplication technology, including two methods:
1. Competition law
The competition method is mostly used for the determination of small molecule antigen substances. Excess antibody coated with magnetic particles is added to the reaction cup and incubated with the antigen to be tested and the quantitative labeled acridinium ester antigen at the same time, so that the labeled antigen and the antibody (or the antigen to be tested and the antibody) combine to form a complex.
2. Sandwich method
The sandwich method is mostly used to determine the antigenic substances of macromolecules. The labeled antibody and the test antigen are combined with the coating antibody at the same time to generate a coating antibody—a complex of the luminescent antibody of the assay antigen.
The immunology analyzer uses certain chemical groups to label antigens or antibodies. The chemical group is oxidized to form an excited state, and in the process of returning to the ground state, it releases photons of a certain wavelength. The photomultiplier tube converts the received light energy into electrical energy, reflects the light measurement in digital form, and then calculates the concentration of the measured object.
This kind of immunoassay analyzer machine applies classical immunological principles, using monoclonal antibody reagents, magnetic particles as solid-phase carriers, alkaline phosphatase as markers, and luminescent agents using 3-(2'-helicaladamantane)-4-methoxy-4 -(3"-phosphoryl oxy)benzene-1,2-dioxetane (AMPPD). Small molecules are determined by the competition method or antibody capture method, while large molecules are determined by the sandwich method.
It is one kind of automatic immunoassay analyzer. The test specimen is mixed with the antibody-coated paramagnetic particles and the luminescent agent-labeled antibody in a reaction cup and incubated together to form a magnetic microbead-coated antibody-antigen-luminescent agent-labeled antibody complex.
When the magnetic particles flow through the surface of the electrode, they are attracted by the magnet installed under the electrode, and the free luminescent agent-labeled antibody is washed away by the buffer. At the same time, a voltage is applied to the electrode to make the luminescent marker ruthenium terpyridine [Ru(bpy)3]2+ carry out electron transfer on the surface of the electrode to produce electrochemiluminescence, and the light intensity is proportional to the concentration of the antigen to be tested. The immunosuppressive method is used for the detection of small molecular weight protein antigens; the sandwich immunoassay is used for the detection of large molecular weight substances.