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  3. Congo Red

Congo Red is an azo dye. Congo Red (CR) binding been used as a diagnostic test for the presence of amyloid in tissue sections.

For research use only. We do not sell to patients.

Congo Red Chemical Structure

Congo Red Chemical Structure

CAS No. : 573-58-0

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10 mM * 1 mL in DMSO
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Customer Review

Based on 1 publication(s) in Google Scholar

Top Publications Citing Use of Products

1 Publications Citing Use of MCE Congo Red

  • Biological Activity

  • Protocol

  • Purity & Documentation

  • References

  • Customer Review

Description

Congo Red is an azo dye. Congo Red (CR) binding been used as a diagnostic test for the presence of amyloid in tissue sections.

In Vitro

Congo Red histochemical stain may serve as a simple screening tool for investigating if the aggregates in mutant cells have misfolded β-pleated sheet secondary structures. Congo Red histochemical dye has the ability to bind specifically to crossed β-pleated sheet structures. Wild-type HSPB1 should maintain protein homeostasis by binding proteins in non-native conformations, thereby preventing substrate aggregation. The T139M mutant, however, fails in this function and results in an accumulation of misfolded proteins, which are targeted by Congo Red for intercalating between the β-pleated sheet structures. Congo Red histochemical stain may serve as a simple tool to investigate if the aggregates in mutant cells have misfolded β-pleated sheet secondary structures[1].

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

Clinical Trial
Molecular Weight

696.66

Formula

C32H22N6Na2O6S2

CAS No.
Appearance

Solid

Color

Pink to red

SMILES

O=S(C1=C2C=CC=CC2=C(N)C(N=NC3=CC=C(C4=CC=C(N=NC5=CC(S(=O)(O[Na])=O)=C6C=CC=CC6=C5N)C=C4)C=C3)=C1)(O[Na])=O

Shipping

Room temperature in continental US; may vary elsewhere.

Storage

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)

Solvent & Solubility
In Vitro: 

DMSO : 20 mg/mL (28.71 mM; Need ultrasonic; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO)

H2O : < 0.1 mg/mL (insoluble)

Preparing
Stock Solutions
Concentration Solvent Mass 1 mg 5 mg 10 mg
1 mM 1.4354 mL 7.1771 mL 14.3542 mL
5 mM 0.2871 mL 1.4354 mL 2.8708 mL
View the Complete Stock Solution Preparation Table

* 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.

  • Molarity Calculator

  • Dilution Calculator

Mass (g) = Concentration (mol/L) × Volume (L) × Molecular Weight (g/mol)

Mass
=
Concentration
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Volume
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Molecular Weight *

Concentration (start) × Volume (start) = Concentration (final) × Volume (final)

This equation is commonly abbreviated as: C1V1 = C2V2

Concentration (start)

C1

×
Volume (start)

V1

=
Concentration (final)

C2

×
Volume (final)

V2

In Vivo:

Select the appropriate dissolution method based on your experimental animal and administration route.

For the following dissolution methods, please ensure to first prepare a clear stock solution using an In Vitro approach and then sequentially add co-solvents:
To ensure reliable experimental results, the clarified stock solution can be appropriately stored based on storage conditions. As for the working solution for in vivo experiments, it is recommended to prepare freshly and use it on the same day.
The percentages shown for the solvents indicate their volumetric ratio in the final prepared solution. If precipitation or phase separation occurs during preparation, heat and/or sonication can be used to aid dissolution.

  • Protocol 1

    Add each solvent one by one:  10% DMSO    40% PEG300    5% Tween-80    45% Saline

    Solubility: ≥ 2 mg/mL (2.87 mM); Clear solution

    This protocol yields a clear solution of ≥ 2 mg/mL (saturation unknown).

    Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (20.0 mg/mL) to 400 μL PEG300, and mix evenly; then add 50 μL Tween-80 and mix evenly; then add 450 μL Saline to adjust the volume to 1 mL.

    Preparation of Saline: Dissolve 0.9 g sodium chloride in ddH₂O and dilute to 100 mL to obtain a clear Saline solution.
  • Protocol 2

    Add each solvent one by one:  10% DMSO    90% (20% SBE-β-CD in Saline)

    Solubility: ≥ 2 mg/mL (2.87 mM); Clear solution

    This protocol yields a clear solution of ≥ 2 mg/mL (saturation unknown).

    Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (20.0 mg/mL) to 900 μL 20% SBE-β-CD in Saline, and mix evenly.

    Preparation of 20% SBE-β-CD in Saline (4°C, storage for one week): 2 g SBE-β-CD powder is dissolved in 10 mL Saline, completely dissolve until clear.
In Vivo Dissolution Calculator
Please enter the basic information of animal experiments:

Dosage

mg/kg

Animal weight
(per animal)

g

Dosing volume
(per animal)

μL

Number of animals

Recommended: Prepare an additional quantity of animals to account for potential losses during experiments.
Please enter your animal formula composition:
%
DMSO +
+
%
Tween-80 +
%
Saline
Recommended: Keep the proportion of DMSO in working solution below 2% if your animal is weak.
The co-solvents required include: DMSO, . All of co-solvents are available by MedChemExpress (MCE). , Tween 80. All of co-solvents are available by MedChemExpress (MCE).
Calculation results:
Working solution concentration: mg/mL
Method for preparing stock solution: mg drug dissolved in μL  DMSO (Stock solution concentration: mg/mL).

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

The concentration of the stock solution you require exceeds the measured solubility. The following solution is for reference only. If necessary, please contact MedChemExpress (MCE).
Method for preparing in vivo working solution for animal experiments: Take μL DMSO stock solution, add μL . μL , mix evenly, next add μL Tween 80, mix evenly, then add μL Saline.
 If the continuous dosing period exceeds half a month, please choose this protocol carefully.
Please ensure that the stock solution in the first step is dissolved to a clear state, and add co-solvents in sequence. You can use ultrasonic heating (ultrasonic cleaner, recommended frequency 20-40 kHz), vortexing, etc. to assist dissolution.
Purity & Documentation
References
Cell Assay
[1]

HeLa cells are selected for these studies due to their large cytoplasmic volume. Cells transfected with mutant or wild-type HSPB1 constructs are grown on coverslips for 24 hr and then are stained with Congo red to determine if the aggregates display amyloidogenic properties. Briefly, cells are first fixed with 10% formalin for 10 min and stained with 1% Congo red for 5 min, followed by destaining with 0.01% potassium hydroxide in 50% ethanol. Coverslips are then passed through graded ethanol concentrations for dehydration and mounted in a mounting medium and examined by fluorescent microscopy under rhodamine filter[1].

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

References

Complete Stock Solution Preparation Table

* 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.

Optional Solvent Concentration Solvent Mass 1 mg 5 mg 10 mg 25 mg
DMSO 1 mM 1.4354 mL 7.1771 mL 14.3542 mL 35.8855 mL
5 mM 0.2871 mL 1.4354 mL 2.8708 mL 7.1771 mL
10 mM 0.1435 mL 0.7177 mL 1.4354 mL 3.5886 mL
15 mM 0.0957 mL 0.4785 mL 0.9569 mL 2.3924 mL
20 mM 0.0718 mL 0.3589 mL 0.7177 mL 1.7943 mL
25 mM 0.0574 mL 0.2871 mL 0.5742 mL 1.4354 mL
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Congo Red Related Classifications

Help & FAQs
  • Do most proteins show cross-species activity?

    Species cross-reactivity must be investigated individually for each product. Many human cytokines will produce a nice response in mouse cell lines, and many mouse proteins will show activity on human cells. Other proteins may have a lower specific activity when used in the opposite species.

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Congo Red
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HY-D0236
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