Commonly used cell staining methods in biological experiments

Staining is one of the most important steps in the preparation of biological microscope slides. First destroy the selective permeability of the cell membrane, and then use the dye to immerse the biological tissue in the dye, so that a certain part of the tissue cells is dyed with a different color or depth of color from other parts, resulting in different refractive indices for observation.

Commonly used cell staining methods are:

1. Simple dyeing method, commonly used basic dyes such as methylene blue for simple dyeing;

2. Gram staining method mainly includes four processes: crystal violet primary staining, iodine mordant staining, ethanol (or acetone) decolorization and safranine counterstaining;

3. Wright's staining method, Wright's dye solvent is mainly composed of eosin methylene blue;

4. Giemsa staining, the principle and results of Giemsa staining are basically the same as those of Reiter staining;

5. Cell immunofluorescence staining, the main principle of immunofluorescence staining is to use the specific binding between antigens and antibodies.

In addition, silver dyeing method is also more commonly used. When the tissue block is immersed in the silver nitrate solution, some tissue structures can directly reduce the silver nitrate, so that the silver particles are attached to it, and it is brown-black or brown-yellow. Some structures have no direct reducing ability to silver nitrate. If a reducing agent is added, silver nitrate can be reduced to precipitate and develop color.

There are physical and chemical methods for staining cells. The physical method is drying and flame fixation. The most commonly used chemical methods are formaldehyde, ethanol, acetone and acetic acid.

1. Azo coupling method: using artificially synthesized enzyme substrates, under the action of enzymes, a decomposition product is produced, and then combined with diazonium salts to cause azo coupling, which forms insoluble azo pigments, which proves that the enzyme The presence.

2. Benzidine method: The peroxidase in granulocytes and monocytes acts on hydrogen peroxide to release new ecological oxygen, so that colorless benzidine forms a blue precipitate.

3. Prussian blue method: intracellular and extracellular iron react with acidic potassium ferrocyanide to form blue ferric ferrocyanide precipitation.

4. Scheff reaction: Periodic acid oxidizes ethylene glycol group in intracellular carbohydrates to form acetaldehyde group, and the aldehyde group reacts with Scheff reagent to make colorless magenta to form red precipitate.

5. Metal deposition method: There are other physical methods, such as fat-soluble dye staining (to display lipids), fluorescence display, autoradiography, and in vitro staining, which are also commonly used in clinical hematological cytology diagnosis.