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M2128 Sigma

Thiazolyl Blue Tetrazolium Bromide


Synonym: 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide, MTT, Methylthiazolyldiphenyl-tetrazolium bromide



Frequently Asked Questions

Frequently Asked Questions are available for this Product.


1, 5, 10 g in glass bottle

100, 250, 500 mg in glass insert


Thiazolyl Blue Tetrazolium Blue (MTT) may be used in measurement of cell proliferation. MTT produces a yellowish solution that is converted to dark blue, water-insoluble MTT formazan by mitochondrial dehydrogenases of living cells. The blue crystals are solubilized with acidified isopropanol and the intensity is measured colorimetrically at 570 nm. MTT has been used as a histochemical/cytochemical reagent and for the detection of NAD. ADP-linked enzyme systems in tissue cannot be detected with MTT, due to binding of the cation by the cyanide trap used. MTT is rapidly reduced to the formazan, which chelates with nickel, copper, and cobalt; the cobalt chelate has been used in oxidative systems.

Thiazolyl Blue Tetrazolium Bromide has been used for the following assays:
• Proliferation assay.
• TNF (tumor necrosis factor) bioassay.

Price and Availability

Tissue Diagnostics

All labs need water

Biomedical Applications
Safety & Documentation

Safety Information

Signal word 
Hazard statements 
Precautionary statements 
NONH for all modes of transport
WGK Germany 

Frequently Asked Questions

Which document(s) contains shelf-life or expiration date information for a given product?
If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis. These documents are located on the product detail page under Useful Links & Tools. Click on the following link to search for a Certificate of Analysis. Please click the following link to see the details on our Product Dating Information.
What can be used to make a solution of Thiazolyl Blue Tetrazolium Bromide (MTT)?
We test the solubility of MTT in water at a concentration of 5 mg/mL.  For the MTT viability assay, we dissolve Product No. M5655 at a concentration of 5 mg/ml in RPMI-1640 without phenol red. This medium is available as a powder (Product No.R8755) or liquid (Product No. R7509). MTT can be solubilized in any culture media or balanced salt solution that does not contain phenol red as a pH indicator.
How can I store solutions of Thiazolyl Blue Tetrazolium Bromide (MTT)?
Reconstituted MTT solution is stable for at least 6 months when stored frozen (-20 °C). Storage of reconstituted MTT solution at 2-8°C for more than 2 weeks may cause decomposition and yield erroneous results.
What can be used to solubilize MTT formazan (the product of the Thiazolyl Blue Tetrazolium Bromide - MTT reaction)?
Mitochondrial dehydrogenases of viable cells cleave the tetrazolium ring of the MTT, yielding purple MTT formazan crystals. These crystals are not soluble in aqueous solutions; they may be dissolved in acidified isopropanol (0.1 N HCl in anhydrous isopropanol). If this does not lyse the cells, Triton X-100 can be added to the acidified isopropanol. A typical working concentration is 10% Triton X-100 (i.e., 1 volume of 100% Triton X-100 + 9 volumes of acidified isopropanol).
Why is a reference wavelength used for data analysis of Thiazolyl Blue Tetrazolium Bromide (MTT)?
The reference wavelength (630-690 nm) is used to adjust for the optical variation in the wells of the plate.  It also corrects for dust and fingerprints that can be present.  The assay is read at 570 nm.  The reference wavelength needs to be far enough away from the assay wavelength so as not to affect those values.
What type of multi-well plate should be used for the Thiazolyl Blue Tetrazolium Bromide (MTT) assay?
It is recommended that flat bottom multi-well plates be used for the MTT assay. The use of tissue culture treated plates is only important if necessary for good cell growth.  If cells are grown in larger plates, the supernatant after cell lysis can be transferred to a 96 well plate for reading.
How do I get lot-specific information or a Certificate of Analysis?
A Certificate of Analysis is available by lot number and can be obtained through our Advanced Search Option: http://www.sigmaaldrich.com/catalog/AdvancedSearchPage.do
How do I find price and availability?
There are several ways to find pricing and availability for our products.  Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers. 
What is the Department of Transportation shipping information for this product?
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, or search here. 
My question is not addressed here, how can I contact Technical Service for assistance?
Use the option to the right to "Ask a Question" by email of a Technical Service Scientist.
Is the MTT assay quantitative?
The MTT asay is a method to assess cell viability.  This assay is a semiquantitative assay. The assay is used to compare the viability changes in treated cells to untreated cells. The absorbance is indicative of the cell number. The higher the absorbance, the greater the number of viable cells present. Most researchers compare the absorbance of the two samples as a ratio (ABS treated cells/ABS untreated cells) to get a fold increase/decrease in cell number.      
How can Thiazolyl Blue Tetrazolium Bromide be used for staining dehydrogenase in tissue sections?
Products M2128 or M5655, Thiazolyl Blue Tetrazolium Bromide can be used for staining dehydrogenase in tissue sections. See the method below.   Reagent Preparation MTT (2 mg/ml distilled water) 2.5 ml 0.2 M Tris buffer, pH 7.4 2.5 ml 0.5 M cobalt chloride 0.5 ml 0.05 M magnesium chloride 1.0 ml Distilled water 2.5 ml The pH of this solution is adjusted to 7.0 if necessary. Aliquot and store at -20°C until required.   Sample Preparation Cut cytostat sections at 5 to 7 microns. Do not fix.   Method: 1. Incubate sections in appropriate incubation solution at 37°C for 30-60 minutes. 2. Transfer sections to 15% formol saline, 15 minutes. 3. Wash in distilled water 4. Counterstain in 2% methyl green if required. 5. Wash in distilled water. 6. Mount in glycerin Jelly.   Results Enzyme: Black formazan deposits with MTT   Source:  Bancroft and Gamble, Theory and Practice of Histological Techniques, Fifth Edition. Churchill Livingstone, London, 2002, page 610.
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Protocols & Articles


Recycling Micro-Assay of β-NAD and β-NADH

1. OBJECTIVE To standardize a procedure for the recycling micro-assay of β-NAD and β-NADH at Sigma-Aldrich Saint Louis.
Keywords: Sonication

Peer-Reviewed Papers


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