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Cell Counting Kit 8 (CCK-8)
Cell Counting Kit 8 (CCK-8) is a colorimetric assay used to quantitate cell proliferation, cell viability and cytotoxicity.
Product Description
CCK-8 utilizes the enzymatic activity of live cells to reduce a colorless compound into an orange dye, formazan. The amount of formazan produced, as determined by absorbance (λ460 nm), is directly proportional to the number of live cells in the sample.
Key Features
- Faster results with improved water solubility compared to MTT assays
- Higher sensitivity compared to MTS or WST-1 assays, enabling detection of live cells at low densities
- Lower cytotoxicity compared to XTT based assays, reducing the noise in the data due to assay components
- Excellent stability allowing for long assays (24 - 48 hours)
- Convenient workflow with a single-component, mix-and-read format
- Enhanced accuracy compared to MTT assays, as it targets total dehydrogenase instead of mitochondrial dehydrogenase activity
Assay Principle
Metabolically active cells are known to produce dehydrogenase enzymes. Under neutral pH conditions and with the aid of an electron acceptor known as 1-methoxy phenazine methosulfate, NADPH-dependent cellular enzymes operate across the cell membrane to mediate the reduction of the colorless, cell-impermeant WST-8 tetrazolium salt. This yields an orange-colored formazan dye which is soluble in cell culture media or aqueous buffers, exhibiting strong absorption at 460 nm. This absorbance is directly proportional to the number of live cells present in the samples, serving as a reliable indicator of cell viability.
What is the difference between CCK-8 and MTT?
CCK-8 assays rely on total cell dehydrogenase activity to reduce WST-8 to an orange formazan dye, which is monitored at λ 460 nm.
MTT assays rely on mitochondrial dehydrogenase activity to reduce MTT to a purple formazan dye, which is monitored at λ 562 nm.
CCK-8 assays are less toxic, more sensitive and more water soluble than MTT assays.
MTT assays rely on mitochondrial dehydrogenase activity to reduce MTT to a purple formazan dye, which is monitored at λ 562 nm.
CCK-8 assays are less toxic, more sensitive and more water soluble than MTT assays.
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What is the difference between CCK-8 and CellTiter-Glo?
CellTiter-Glo is a luminescence assay that relies on production of oxyluciferin from exogenous luciferin, catalyzed by luciferase in the presence of ATP from metabolically active cells.
CCK-8 is a colorimetric assay that relies on production of formazan from WST-8, catalyzed by endogenous cellular dehydrogenase in the presence of NADPH from metabolically active cells.
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CCK-8 is a colorimetric assay that relies on production of formazan from WST-8, catalyzed by endogenous cellular dehydrogenase in the presence of NADPH from metabolically active cells.
What is the formula for CCK-8?
CCK-8 uses WST-8 as the primary reagent for detecting cell viability.
The chemical name of WST-8 is 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium monosodium salt.
The molecular formula for WST-8 is C20H14N6NaO11S2+.
The SMILES of WST-8 is COC1=C(C=CC(=C1)N+[O-])[N+]2=NC(=NN2C3=CC=C(C=C3)N+[O-])C4=C(C=C(C=C4)S(=O)(=O)O)S(=O)(=O)[O-].[Na+].
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The chemical name of WST-8 is 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H tetrazolium monosodium salt.
The molecular formula for WST-8 is C20H14N6NaO11S2+.
The SMILES of WST-8 is COC1=C(C=CC(=C1)N+[O-])[N+]2=NC(=NN2C3=CC=C(C=C3)N+[O-])C4=C(C=C(C=C4)S(=O)(=O)O)S(=O)(=O)[O-].[Na+].
What is the OD value of CCK-8?
CCK-8 is a colorimetric assay. The assay results can be read using an absorbance spectrophotometer. The resulting optical density (OD) value is proportional to the number of viable cells. The maximum OD value for CCK-8 occurs at 460 nm.
Is CCK-8 light sensitive?
CCK-8 should be stored so as to minimize light exposure. The recommended storage condition is < -15 °C.
| Catalog | Size | Price | Quantity |
|---|---|---|---|
| 22772 | 1000 Tests | Price | |
| 22773 | 10000 Tests | Price |
Storage, safety and handling
| H-phrase | H303, H313, H333 |
| Hazard symbol | XN |
| Intended use | Research Use Only (RUO) |
| R-phrase | R20, R21, R22 |
| Storage | Freeze (< -15 °C); Minimize light exposure |
| UNSPSC | 12352200 |
Instrument settings
| Absorbance microplate reader | |
| Absorbance | 460 nm |
| Recommended plate | Clear bottom |
Contact us
| Telephone | |
| Fax | |
| sales@aatbio.com | |
| International | See distributors |
| Bulk request | Inquire |
| Custom size | Inquire |
| Technical Support | Contact us |
| Request quotation | Request |
| Purchase order | Send to sales@aatbio.com |
| Shipping | Standard overnight for United States, inquire for international |
Page updated on October 13, 2025