Mucin stain solution (azur A method)

There are many methods for staining mucus, such as AB-PAS staining, HID-AB staining and standard Alcian blue staining, etc. Most of these methods use the principle of alcian blue (cationic dye) that can combine with acidic groups. Alcian blue forms insoluble complexes with anionic groups such as carboxyl and sulfate groups contained in tissues.

Azure A mucin stain solution (Azure A method) uses the metachromatic property of Azure A. After staining, the color of the tissue or tissue components is obviously different from the original color of the dye complex and can form a sharp contrast. After staining, the section processing is very important for the stability of metachromatic staining, and ethanol is preferably used for preservation.