Merck, 05500-25G, Alcian Blue 8GX

General description
Alcian Blue 8GX (Cl 74240), also known as Alcian Blue 8GN or Ingrain Blue 1, is a cationic, copper phthalocyanine dye. Four cationic guanidinium groups are attached to the ring system via thioether links, which form an insoluble pigment when broken by hydroxide ions or nucleophiles. The dye is basic, tetravalent, and blue in color due to its copper content. It forms salt linkages with the acid groups of acid mucopolysaccharides.
Application

• Alcian Blue 8GX is generally used for the demonstration of mucopolysaccharides and as a general microscopic stain.
• It is a heteroglycan stain for neutral, sulfated, and phosphated mucopolysaccharides and glycosaminoglycans in tissues such as cartilage and extracellular matrices.
• It has been used to discover novel insights into the short-term impact of food-relevant synthetic amorphous silica on the intestinal epithelium.
• It is suitable for amyloid staining, cystine following oxidation, and staining mast cells in polychromatic alcian blue-safranine methods.
• It is applicable as a microscopic stain for the detection of bacterial capsules, and mucin staining of cytological fine-needle aspirates.

Biochem/physiol Actions
Alcian blue staining can be combined with the Periodic acid-Schiff (PAS) reaction. Acid mucosubstances in tissues are stained selectively and counterstained most commonly with nuclear fast red. This can be combined with the PAS reaction to additionally visualize non-substituted polysaccharides, neutral mucopolysaccharides, muco- and glycoproteins, and glycol- and phospholipids, using an Acetic acid-Alcian blue solution as the stain. Carboxylated and sulfatic proteoglycans are selectively stained at a pH of 2.5. The differentiation between carboxyl and sulfate groups is only possible at pH 1.
Alcian Blue 8GX forms insoluble complexes with acidic glycosaminoglycans, thereby helping in the quantitative determination of glycosaminoglycans.
Features and Benefits

• Desired staining patterns can be obtained by manipulating pH and salt concentrations.