Comparison between chemiluminescence and enzyme-linked immunoassay
The basic principle of chemiluminescence method is to use chemiluminescence to measure the reactants, catalysts, sensitizers and inhibitors of chemiluminescence reactions, reactants, catalysts and sensitizers in the coupling reaction.
The basic principle of enzyme-linked immunoassay: ① make antigen or antibody bind to the surface of a certain solid phase carrier and maintain its immunological activity. ② The antigen or antibody is linked to an enzyme to form an enzyme-labeled antigen or antibody. This enzyme-labeled antigen or antibody retains its immunological activity while retaining the enzyme activity. During the measurement, the test specimen (the antibody or antigen therein) and the enzyme-labeled antigen or antibody are reacted with the antigen or antibody on the surface of the solid phase carrier in different steps. The antigen-antibody complex formed on the solid phase carrier is separated from other substances by washing, and finally the amount of enzyme bound on the solid phase carrier is in a certain proportion to the amount of the tested substance in the specimen. After adding the substrate for the enzyme reaction, the substrate is catalyzed by the enzyme to become a colored product. The amount of the product is directly related to the amount of the test substance in the specimen, so qualitative or quantitative analysis can be performed according to the depth of the color reaction. Since the catalytic frequency of the enzyme is very high, the reaction effect can be greatly amplified, so that the determination method reaches a high sensitivity.
Picture of chemiluminescence
The advantages and disadvantages of the two methods
Advantages: It uses the energy generated by the chemical reaction to excite and emit light. It has the advantages of simple instrument, low detection limit and wide linear range. It is widely used in chemical analysis. Compared with the fluorescence method, the chemiluminescence method does not require an external light source, thereby reducing light scattering, reducing the interference of noise signals, improving the detection sensitivity, and expanding the linear dynamic range.
Disadvantages: poor selectivity, will react to a series of compounds, rather than a single compound. Another disadvantage is that the emission intensity of chemiluminescence depends on various environmental factors. In different environmental systems, the curve of emission intensity and time has a large difference. Therefore, various external factors must be strictly controlled.
Advantages: 1. Enzyme-linked immunosorbent experiment technology that adsorbs the known antigen or antibody on the surface of the solid phase carrier, so that the enzyme-labeled antigen antibody reacts on the surface of the solid phase. This technique can be used to detect macromolecular antigens and specific antibodies.
2. Immunological detection technology has the advantages of fast detection speed, low cost, simple and portable instrument, high sensitivity and strong selectivity, and can be used for on-site inspection. It combines the amplification of the enzyme-catalyzed reaction with the high specificity and specificity of the antigen-antibody affinity reaction, and uses the enzyme-labeled antigen or antibody as the main reagent for immunoassay, so it has high sensitivity.
Disadvantages: 1. It is only an auxiliary method of diagnosis, and the specificity and sensitivity need to be improved.
2. The operation process is a bit tedious, the reaction takes time and cannot be done overnight.
HEPES, as a zwitterionic buffer, increases the osmotic pressure of the cell culture system by increasing the concentration of solution ions, maintaining normal cell morphology and function, and improving cell survival rate. Widely used in cell culture, especially under specific conditions such as tumor cell culture, it is crucial to maintain cell growth and function.