Acridine orange, C.I. 46005, is a cationic fluorescent nucleic-acid dye used for differential staining and analysis of DNA and RNA. Its interactions with nucleic acids produce fluorescence responses that vary with nucleic-acid structure, dye concentration, pH, and the local molecular environment.
Synonyms: Acridine orange hydrochloride; C.I. 46005; C.I. Basic Orange 14; 3,6-bis(dimethylamino)acridine hydrochloride.
Chemical purity is ≥95%, and this grade is free of inorganic salts. The listed λmax is 494 ± 4 nm; this spectral specification should not be interpreted as a complete fluorescence excitation/emission pair.
Key Properties
- Cationic fluorescent nucleic-acid dye
- C.I. number: 46005
- CAS Number: 65-61-2
- Chemical purity: ≥95%
- Molecular weight: 301.83 g/mol
- Melting point: 284–287°C
- λmax: 494 ± 4 nm
- Free of inorganic salts
- Physical form: dark orange solid
- Catalog number: 04539
- Package size: 1 g
- Storage: below 0°C
Applications
DNA & RNA Staining
Acridine orange is used in fluorescence-based nucleic-acid staining of DNA and RNA. Its spectral response depends on nucleic-acid association and staining conditions, allowing differential analysis in appropriately validated fluorescence methods.
Fluorescence Microscopy
Acridine orange is used in microscopy workflows for visualization and analysis of nucleic acids. Dye concentration, pH, sample preparation, and optical configuration should be kept consistent when fluorescence intensity or spectral behavior is compared between samples.
Flow Cytometry
Acridine orange staining has been used in flow-cytometric research methods for simultaneous assessment of cellular DNA and RNA content. Instrument settings, staining conditions, and sample preparation should be defined for the specific analytical method.
Nucleic-Acid Gel Analysis
Acridine orange has also been used in research methods for analysis of single- and double-stranded nucleic acids in polyacrylamide and agarose gels.
Staining & Spectral Considerations
- The listed λmax of 494 ± 4 nm is a spectral specification and should not be treated as a complete fluorescence excitation/emission pair
- Acridine orange binds both DNA and RNA and should not be treated as an inherently RNA-specific dye
- Fluorescence response varies with nucleic-acid structure, dye concentration, pH, and molecular environment
- Use consistent staining and optical conditions when making quantitative comparisons
Observed fluorescence characteristics depend on the staining protocol and sample environment. Excitation and emission settings should therefore be selected for the specific assay rather than inferred solely from the listed λmax.
Application Tips
- For the RNA-focused staining method associated with this grade, use a 2% acridine orange solution containing 1% lanthanum acetate in 15% acetic acid
- Keep dye concentration, pH, and staining time consistent when comparing fluorescence between samples
- Maintain consistent microscope or flow-cytometer acquisition settings for quantitative workflows
- Validate fluorescence interpretation under the conditions of the specific staining method
Handling & Storage
- Store below 0°C in a cool, well-ventilated location
- Handle in a chemical fume hood or with effective local exhaust ventilation
- Wear protective gloves, safety glasses, and suitable protective clothing
- Avoid breathing dust and minimize direct skin contact
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FAQ
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1. What is acridine orange used for?
Acridine orange is used as a fluorescent nucleic-acid stain in research involving DNA and RNA, including fluorescence microscopy, flow cytometry, and nucleic-acid analysis methods.
2. Does acridine orange stain both DNA and RNA?
Yes. Acridine orange interacts with both DNA and RNA. Its fluorescence response varies with nucleic-acid structure, dye concentration, pH, and staining conditions, so it should not be considered inherently specific for RNA.
3. What does the 494 ± 4 nm λmax mean?
The listed λmax is 494 ± 4 nm. It should not be interpreted as a complete fluorescence excitation/emission pair because acridine orange fluorescence depends on its molecular environment and assay conditions.
4. Can acridine orange be used for flow cytometry?
Yes. Acridine orange has been used in flow-cytometric research methods for measuring cellular DNA and RNA. Staining conditions and instrument settings should be defined for the specific method.
5. What package size is available and how should acridine orange be stored?
Catalog 04539 is available in a 1 g package and should be stored below 0°C. For larger quantities, use the bulk-quote option.
Safety & Documentation
Handle acridine orange with appropriate laboratory ventilation and personal protective equipment. Avoid inhalation, ingestion, and direct skin exposure. Refer to the current Safety Data Sheet (SDS) for complete hazard, handling, storage, and disposal information.
