Direct Red 80  (Synonyms: Sirius Red)

Direct Red 80 (Sirius Red) is a polyazo dye used principally in staining methods for collagen and amyloid. Direct Red 80 does not release benzidine upon degradation and is safer than many traditional direct dyes^[1].

Direct Red 80 (Sirius Red) has two important uses in histopathology: staining collagen from solution in saturated aqueous picric acid and staining amyloid from an alkaline solution. Stained structures are red^[1].
Confocal laser microscopy (CLM) is also used to evaluate collagen production and distribution after Direct Red 80 staining. Direct Red 80 is not specific for the different types of collagen. Samples are washed in dH₂O, pretreats for 40 min with a solution of 0.2% phosphomolybdic acid (PMA) and incubates for 30 min in a solution consisting of 0.1% Direct red 80 diluted in saturated aqueous picric acid. Finally each sample is washed in 0.01 M HCl for 2 min. PMA is used to make colourless cytoplasm and HCl is used to remove non-specific staining^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

1373.07

C₄₅H₂₆N₁₀Na₆O₂₁S₆

2610-10-8

Solid

Brown to reddish brown

O=C(NC1=CC2=CC(S(=O)(O[Na])=O)=C(/N=N/C3=CC=C(/N=N/C4=CC=C(S(=O)(O[Na])=O)C=C4)C=C3S(=O)(O[Na])=O)C(O)=C2C=C1)NC5=CC6=CC(S(=O)(O[Na])=O)=C(/N=N/C7=CC=C(/N=N/C8=CC=C(S(=O)(O[Na])=O)C=C8)C=C7S(=O)(O[Na])=O)C(O)=C6C=C5

Room temperature in continental US; may vary elsewhere.

4°C, sealed storage, away from moisture and light

*In solvent : -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light)

* Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.
Storage method and period of stock solution: -80°C, 6 months; -20°C, 1 month (sealed storage, away from moisture and light). When stored at -80°C, please use it within 6 months. When stored at -20°C, please use it within 1 month.

• [1]. Dapson RW, et al. Certification procedures for sirius red F3B (CI 35780, Direct red 80). Biotech Histochem. 2011;86(3):133-139.  [Content Brief]