Download Neutral Red Cell Culture Tested Product Number - Sigma

Neutral Red
Cell Culture Tested
Product Number N4638
Storage Temperature 2-8 °C
Product Description
Molecular Formula: C15H17ClN4
Molecular Weight: 288.8
CAS Number: 553-24-2
C.I. Number: 50040
1
λmax : 539-544 nm (50% ethanol, 0.5% acetic acid)
1
Synonyms: toluylene red, basic red 5
Neutral Red is a weak cationic azine dye that is used
extensively as a nuclear stain in a variety of biological
stain applications. It is a pH indicator as well,
changing color from red to yellow over the pH range
1,2
6.8-8.0.
It is also incorporated into bacteriological
growth media.
This product is often used for supravital staining of
fresh peripheral blood. It can also be used for staining
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Nissl granules of neuroglial cells. However, this stain
in not as permanent as another dye, Cresyl Violet
acetate, for this application. Buffered 0.5% Neutral
Red solutions are used as a counterstain for Naphthol
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AS acetate esterase, peroxidase and iron stains.
Solutions can also be used to stain plankton for
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viability. Using 1 part Neutral Red to 10,000 parts
sea water, dead cells were stained red and live cells
remained unchanged. In addition, aqueous solutions
of Neutral Red (0.1% in saline, pH 6.5) can be used as
3,6
a fluorescent stain for lipids . Lipids will fluoresce
blue-geen or yellow, depending on their composition.
It has been used also as a Twort's stain for parasites
8
in combination with Light Green SF, as a general
histological stain for embryonic tissue in combination
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with Janus green, and for demostrating hydrolysis of
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fats. It can also be used in conjunction with Luxol
Fast Blue for staining tissues embedded in glycol
methacrylate: myelin sheaths stain blue, connective
tissue stain blue to light purple, and nuclei and
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cytoplasmic basophilic structures are red.
Neutral Red is most commonly used for cytotoxicity
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assays to determine cell viability. The dye readily
penetrates cell membranes of viable cells by diffusion
and accumulates in the lysosomes. After the cells are
allowed to incorporate the dye, they are briefly washed
or fixed. The incorporated dye is then released from
the cells and quantitated spectrophotometrically. The
change in the level of dye incorporation reflects an
increase or decrease in the number of viable cells or
their physiological state. This indicates the degree of
cytotoxicity caused by the test material, making it
possible to distinguish between viable, damaged, or
dead cells. This assay forms the basis for the In Vitro
Toxicology Kit, Product Code TOX-4.
Precautions and Disclaimer
For Laboratory Use Only. Not for drug, household or
other uses.
References
1. Sigma-Aldrich Handbook of Stains, Dyes, and
Indicators, Green, F. J., Aldrich Chemical Co.
(Milwaukee, WI: 1990), p. 504.
2. Conn's Biological Stains, 9th ed., Lillie, R. D.,
Williams and Wilkins (Baltimore, MD: 1977),
p. 378.
3. Staining Procedures, 4th ed., Clark, G., ed.,
Williams and Wilkins (Baltimore, MD: 1981),
pp. 142-143.
4. Atlas of Cytochemistry & Immunochemistry of
Hematologic Neoplasms, Sun, T., et al., American
Society of Clinical Pathologists Press (Chicago, IL:
1985).
5. Crippen, R. W., and Perrier, J. L., The use of
Neutral red and Evan's blue for live-dead
determinations of marine plankton. Stain Technol.,
49(2), 97-104 (1974).
6. Kirk, P. W., Jr., Neutral red as a lipid
fluorochrome. Stain Techol., 45(1), 1-4 (1970).
7.
8.
Borenfreund, E., and Puerner, J. A., Toxicity
determined in vitro by morphological alterations
and neutral red absorption. Toxicol. Lett. 24(2-3),
119-124 (1985).
Twort, F. W., An improved neutral red, light green
double stain, for staining animal parasites, microorganisms and tissues. J. State Med. (London),
32, 351-355 (1924).
9.
Faris, H. A., Neutral red and janus green as
histological stains. Anat. Rec., 27, 241-244 (1924).
10. Knaysi, G. Further studies on the use of basic
dyes for measuring hydrolysis of fats. J. Dairy Sci.,
25, 585-588 (1942).
CMH/RXR 5/06
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