Neutral Red
Neutral Red is a versatile cell-permeable dye widely used in biological research for cell viability assays, lysosome tracking, and pH indicator applications. This phenazine dye exhibits a color change from red to yellow as pH decreases, making it particularly useful for studying acidic compartments within cells.
Product Specifications
- Chemical Name: 3-Amino-7-dimethylamino-2-methylphenazine hydrochloride
- Molecular Formula: C15H17ClN4
- Molecular Weight: 288.78 g/mol
- Appearance: Dark green to brown powder
- Solubility: Soluble in water, ethanol, and methanol
- Absorption Maximum: 540 nm (pH 7.0)
- Emission Maximum: 640 nm
- Purity: ≥90% (HPLC)
| Parameter | Specification |
|---|---|
| Storage Temperature | 2-8°C (protect from light) |
| Shelf Life | 24 months from date of manufacture |
| Working Concentration | Typically 10-50 μg/mL in cell culture |
| pH Sensitivity Range | 6.8 (red) to 8.0 (yellow) |
| Extinction Coefficient | 46,000 cm⁻¹M⁻¹ at 540 nm (pH 7.0) |
Applications of Neutral Red
Neutral Red serves multiple purposes in biological research:
- Cell Viability Assays: Living cells actively take up and retain Neutral Red, while dead cells cannot.
- Lysosomal Tracking: The dye accumulates in acidic compartments like lysosomes.
- pH Indicator: Color changes indicate pH variations in cellular compartments.
- Toxicity Testing: Used in ecotoxicology to assess chemical impacts on cells.
- Photodynamic Therapy: Acts as a photosensitizer in some therapeutic applications.
Neutral Red FAQ
Q: What precautions should I take when handling Neutral Red?
A: Always wear appropriate personal protective equipment including gloves and eye protection. Avoid inhalation and contact with skin. Neutral Red may be harmful if swallowed and may cause eye irritation. Work in a well-ventilated area and follow standard laboratory safety protocols.
Q: How should I prepare a stock solution of Neutral Red?
A: Dissolve Neutral Red powder in sterile PBS or culture medium at a concentration of 1 mg/mL. Filter sterilize through a 0.2 μm filter. The stock solution can be stored at 4°C protected from light for up to 2 weeks. For cell viability assays, dilute to a final concentration of 50 μg/mL in culture medium.
Q: Why is Neutral Red used in cell viability assays?
A: Neutral Red is selectively taken up by viable cells through active transport mechanisms. The dye accumulates in lysosomes of living cells, while non-viable cells cannot retain the dye. After incubation, extraction of the dye from cells and measurement of absorbance provides a quantitative measure of cell viability proportional to the number of living cells.
Technical Considerations
| Application | Recommended Protocol |
|---|---|
| Cell Viability Assay | Incubate cells with 50 μg/mL Neutral Red for 2-3 hours, then extract with acidified ethanol (50% ethanol, 1% glacial acetic acid) |
| Lysosome Staining | Use 10-20 μg/mL solution for 15-30 minutes, then wash cells with PBS before imaging |
| pH Indicator | Prepare solutions at known pH values (6.5-8.0) to create standard curve for comparison |
Quality Assurance
Our Neutral Red undergoes rigorous quality control testing:
- HPLC purity verification (≥90%)
- Mass spectrometry confirmation of molecular weight
- Absorbance spectrum validation
- Biological activity testing in standard cell lines
- Endotoxin level testing for cell culture applications
Ordering Information
| Package Size | Catalog Number | Price |
|---|---|---|
| 1 g | NR-100 | $85.00 |
| 5 g | NR-500 | $350.00 |
| 25 g | NR-2500 | $1,500.00 |
For bulk orders or custom formulations, please contact our technical support team. Special packaging options are available for international shipping requirements.