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Congo red solid and in water solution. Congo red is an organic compound, the sodium salt of 3,3′- ( [1,1′-biphenyl]-4,4′-diyl)bis (4-aminonaphthalene-1-sulfonic acid). It is an azo dye. Congo red is water-soluble, yielding a red colloidal solution; its solubility is greater in organic solvents.
Congo red is a direct diazo dye that stains amyloid deposits in tissue sections with apple green birefringence. Learn about the definition, pathophysiology, clinical features, interpretation and uses of Congo red stain for amyloidosis diagnosis.
Congo red, first of the synthetic dyestuffs of the direct type, that is, not requiring application of a mordant (a substance such as tannin or alum used to fix the colour to cotton fibres). Introduced in 1884, Congo red belongs to a group of azo dyes derived from benzidine.
Congo Red is the sodium salt of benzidinediazo-bis-1-naphthylamine-4-sulfonic acid; a diazo dye that is red in alkaline solution and blue in acid solution and used especially as an indicator and as a biological stain.
In 1884 Bottiger discovered that the diazo dye, Congo Red, coloured cotton without the necessity for pre-treatment with a metal salt (a so-called ‘mordant’). This finding led to the synthesis of related dyes which were referred to as the ‘direct’ dyes due to their ease of application.
Congo red is a benzidine-based anionic diazo dye. It is a histological dye which binds to many amyloid proteins and is used for the quantification of amyloid β-peptide aggregation. [5] Congo red also interacts with β-D-glucans, polysaccharides containing continuous β-(1→4)-linked D-glucopyranosyl units and some hemicellulosic ...
Jan 1, 2019 · Staining with Congo Red dye (CR) is one of the major methods used to detect the amyloid structure of protein aggregates. However, a series of experiments have shown that CR staining is insufficient for confirmation of the amyloid nature of protein aggregates.
