The history of immunology began with the study of Microbiology, established in the 18th century, and entered the classic development period from the 19th century to the mid-20th century. During this period, people's understanding of immune function entered the period of scientific experiment from the observation of human body phenomenon.
From the early to the middle of the 20th century, it entered the period of modern immunology. From the middle of the 20th century, it really entered the period of modern immunology. The detection of modern immunology has gone through the following processes.
The specific reaction of antigen and antibody is used to detect, and isotope, enzyme and chemiluminescence are used to amplify and display the detection signal. It is often used to detect protein, hormone and other trace substances. Immunodiagnosis plays a very important role in clinical diagnosis. The common immunotechnologies include radioimmunoassay, enzyme-linked immunosorbent assay, chemiluminescence, electrochemiluminescence and chemiluminescence of magnetic nanoparticles.
1. Principles of radioimmunoassay
The radiolabeled antigen and unlabeled antigen (to be tested) were competitively combined with insufficient specific antibodies, and the amount of unlabeled antigen was obtained by separating and measuring the radioactivity after reaction.
2. Principle of enzyme linked immunosorbent assay
Referred to as ELISA, its center is to let the antibody and enzyme complex binding, and then through the color to detect. The antigen or antibody can be bound to the surface of a solid carrier and keep its immune activity. To make an antigen or antibody linked with an enzyme to form an enzyme-linked antigen or antibody. The enzyme-linked antigen or antibody retains both its immune activity and the activity of the enzyme. Because of the high catalytic frequency of enzyme, it can greatly enlarge the reaction effect and make the determination method reach high sensitivity. ELISA can be used to determine antigen and antibody.
3. Principle of chemiluminescence Technology
The free energy released by the chemical reaction is used to excite the intermediate and make it return to the ground state from the excited state. When the intermediate returns to the ground state from the excited state, it will release equal level photons. Chemiluminescence has the specificity of fluorescence, at the same time, it does not need to excite luminescence, which avoids the influence of stray light of excitation light in fluorescence analysis, so as to improve the sensitivity, and avoid the environmental pollution and health hazards caused by radiation analysis. It is a very excellent quantitative analysis method.
4. Principle of electrochemiluminescence Technology
Electrochemiluminescence (ECL) is the result of the participation of electric field in chemiluminescence, which refers to the electrochemical reaction by applying a certain voltage: the TPA on the electrode surface releases electrons, and then releases protons to become free radical TPA *, at the same time, the divalent Ru (bpy) 3] 2 + releases electrons to become trivalent Ru (bpy) 3 + 3 +. There are still divalent Ru (bpy) 3] 2 + and tPA in the reaction system, so that the electrochemical reaction on the electrode surface can continue. In this way, the whole reaction process can be continuously cycled, and the detection signal is continuously amplified, so the detection sensitivity is greatly improved, so the ECL determination has the characteristics of high sensitivity.
5. Principle of chemiluminescence immunoassay with magnetic particles
It is a new analytical method that combines magnetic separation technology, chemiluminescence technology and immunoassay technology. The technology makes full use of the rapidity and automaticity of magnetic separation technology, the high sensitivity of chemiluminescence technology and the specificity of immunoassay. It plays an irreplaceable role in the field of biological analysis. At present, magnetic particle chemiluminescence immunoassay has been used in tubular chemiluminescence immunoassay and electrochemiluminescence immunoassay.
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