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Congo red is water-soluble, yielding a red colloidal solution; its solubility is greater in organic solvents. The use of Congo red in the textile industry has long been abandoned, primarily because of its carcinogenic properties, [1] but it is still used for histological staining .
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.
Jan 1, 2019 · Staining with Congo Red (CR) is a qualitative method used for the identification of amyloids in vitro and in tissue sections. However, the drawbacks and artefacts obtained when using this dye can be found both in vitro and in vivo.
Congo red is a reactive agent that changes color from red to dark blue in acidic environments where the pH is less than 3. Acid producing mucosa turns blue within a few minutes, whereas non–acid-producing mucosa remains red.
Congo Red. Congo Red is a linear molecule that is widely used as a staining reagent in the histopathological diagnosis of amyloid fibrils, as it binds with these fibrils and produces a characteristic yellow-green birefringence under polarized light. AI generated definition based on: Carbohydrate Polymers, 2021
Feb 26, 2020 · It not only stains such proteins red, but undergoes a striking color change to green (birefringence) as the angle of polarized light is changed, a phenomenon also realized around this time. Congo Red is still used for that purpose today, actually, even though we have numerous other techniques to distinguish proteins in tissue samples.
Sep 8, 2014 · “Congo red” is not the name of a famous African explorer, but a dye that dates to 1883. It was synthesized by P. Böttiger as a textile dye, but it subsequently became more important as a pH indicator. It colors aqueous solutions blue below pH 3.0 and becomes red above pH 5.0.
