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C6277

Sigma-Aldrich

Congo Red

Dye content, ≥85%, certified by the Biological Stain Commission, powder

Synonym(s):

Congo Red 4B, Cosmos Red, Cotton Red B, Cotton Red C, Direct Red 28, Direct Red R, Direct Red Y

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About This Item

Empirical Formula (Hill Notation):
C32H22N6Na2O6S2
CAS Number:
Molecular Weight:
696.66
Colour Index Number:
22120
Beilstein:
3894858
EC Number:
MDL number:
UNSPSC Code:
12171500
PubChem Substance ID:
NACRES:
NA.47
Pricing and availability is not currently available.

Product Name

Congo Red, certified by the Biological Stain Commission, BioXtra

grade

certified by the Biological Stain Commission

Quality Level

product line

BioXtra

form

powder

composition

Dye content, ≥85%

technique(s)

microbe id | staining: suitable

mp

>360 °C (lit.)

solubility

H2O: 10 mg/mL

application(s)

diagnostic assay manufacturing
hematology
histology

storage temp.

room temp

SMILES string

[Na+].[Na+].Nc1c(cc(c2ccccc12)S([O-])(=O)=O)\N=N\c3ccc(cc3)-c4ccc(cc4)\N=N\c5cc(c6ccccc6c5N)S([O-])(=O)=O

InChI

1S/C32H24N6O6S2.2Na/c33-31-25-7-3-1-5-23(25)29(45(39,40)41)17-27(31)37-35-21-13-9-19(10-14-21)20-11-15-22(16-12-20)36-38-28-18-30(46(42,43)44)24-6-2-4-8-26(24)32(28)34;;/h1-18H,33-34H2,(H,39,40,41)(H,42,43,44);;/q;2*+1/p-2/b37-35+,38-36+;;

InChI key

IQFVPQOLBLOTPF-HKXUKFGYSA-L

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Application

Congo red has been used for the staining of β amyloid peptides.[1][2][3]

Biochem/physiol Actions

Congo red is a benzidine-based anionic diazo dye.[4] 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 galactoglucomannans.[6]

Suitability

Certified for use as a counterstain for alum based hematoxylin and in the Highman or the Churukian modification of Puchtler′s amyloid stain.

Pictograms

Health hazard

Signal Word

Danger

Hazard Statements

Hazard Classifications

Carc. 1B - Repr. 2

Storage Class Code

6.1C - Combustible acute toxic Cat.3 / toxic compounds or compounds which causing chronic effects

WGK

WGK 3

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Certificates of Analysis (COA)

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Long-term treatment of thalidomide ameliorates amyloid-like pathology through inhibition of ?-secretase in a mouse model of Alzheimer's disease.
He P, et al.
PLoS ONE, 8, e55091-e55091 (2013)
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Journal of pediatric gastroenterology and nutrition, 68(4), 509-516 (2018-11-13)
Enteric bacterial pathogens cause diarrheal disease and mortality at significant rates throughout the world, particularly in children younger than 5 years. Our ability to combat bacterial pathogens has been hindered by antibiotic resistance, a lack of effective vaccines, and accurate
Efficient imaging of amyloid deposits in Drosophila models of human amyloidoses.
Berg I, et al.
Nature Protocols, 5, 935-935 (2010)
Quantifying amyloid beta-peptide (Abeta) aggregation using the Congo red-Abeta (CR-abeta) spectrophotometric assay.
Klunk WE, et al.
Analytical Biochemistry, 266, 66-66 (1999)
Eric K Chu et al.
Nature communications, 9(1), 4087-4087 (2018-10-07)
Bacterial biofilms represent an important medical problem; however, the mechanisms of the onset of biofilm formation are poorly understood. Here, using new controlled methods allowing high-throughput and reproducible biofilm growth, we show that biofilm formation is linked to self-imposed mechanical

Questions

1–3 of 3 Questions  
  1. looking for Congo Red stain, the one used in histopathology, but not sure which of the options is the best.

    1 answer
    1. The dry powder form allows for the preparation of Congo Red for various uses. The recommended dry dye for ordering is C6277 is currently undergoing BSC certification. Congo Red is a dye used for various staining procedures, mostly for staining of amyloid.

      Helpful?

  2. What is the Department of Transportation shipping information for this product?

    1 answer
    1. Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product.

      Helpful?

  3. Why does the SDS for Congo Red list carcinogen as an OSHA hazard, (Section 2) but in Section 11 on carcinogenicity, it states that there is no component identified as a carcinogen?

    1 answer
    1. The reason that there is not an OSHA listing for carcinogens on most of SDS that have a hazard of a carcinogen hazard is because that section of the SDS is specifically for the OSHA regulated carcinogens, also referred to as the OSHA 13. Congo red at this time is not specifically called out  as a carcinogen by the other 3 Organizations listed (IARC, NTP, ACGIH) either. Congo red is listed by the European Classification Labeling & Packaging (CLP) Regulation (which is a pretty definitive guide for hazard classification), as a carcinogen. No other organizations have had the time to classify this material at this time. This is why it is only listed as a carcinogen in section 2 and in section 15.

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