Alcian blue 8 GS (C.l. 74240)

Alcian blue is a dye used in histology to identify mucus-producing tumors, acidic mucins, and sulfated glycosaminoglycans (such as hyaluronic acid or chondroitin sulfate) at a low pH (1.0 to 2.5) to selectively stain cyan.

Due to the isothiouronium groups in solution, Alcian Blue is unstable at higher pH and room temperature, while the water-insoluble phthalocyanine Blue product produced by washing is stable at neutral or basic pH.

The absorption maximum of Alcian blue is between 600 and 610 nm (Alcian blue aggregates), and the rarer monomer form has an absorption maximum at 670 to 680 nm. Alcian blue also colors Suramin. With increasing ionic strength, coloring with Alcian blue is prevented, so that a characteristic salt concentration (critical electrolyte concentration, CEC) can be determined, beyond which coloring no longer takes place. Alcian green is created by mixing Alcian blue with Alcian yellow.

In histology, the derivative Alcian blue 8G (formerly 8GX) is mainly used for Alcian blue staining.

Alcian Blue is also used as a cationic aromatic adhesive for attaching thin slices embedded in glycol methacrylate. Alcian blue binds to cell membranes and can also be used to coat cells in preparation for electron microscopy. After the dye layer has been removed, the inside of the cell membrane can be viewed on it. Alcian blue can also be used as a substitute for polylysine for coating cell culture flasks for adherent cells.