For sales & orders : / For techical support :
: +86-23-67567091
Cell Counting Kit-8, CCK8 Cell Viability Assay Kit

Catalog #BAR1006
Size500 T
In stockYes
Datasheet MSDS

1. CCK8 is WST-8 based cell viability assay kit which was widely used for cell proliferation and cytotoxicity assay.
2. WST-8(2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium) is reduced by dehydrogenases of cell mitochondria, combined with PMS electron mediator, and yield a water-soluble formazan. The faster of the cell proliferation, the deeper of the color. The greater of the cell cytotoxicity, the lighter of the color.
3. WST-8 is better than MTT, XTT, MTS. WST-1 and in particular WST-8 are advantageous over MTT in that they are reduced outside cells, combined with PMS electron mediator, and yield a water-soluble formazan. Finally, WST assays can be read directly (unlike MTT that needs a solubilization step), give a more effective signal than MTT, and decrease toxicity to cells (unlike cell-permeable MTT, and its insoluble formazan that accumulate inside cells). WST-8 is more stable and sensitive than XTT and MTS, which can ensure the stable and high sensitive results. In addition, compare to WST-1, WST-8 is also more sensitive and stable than WST-1, and can be easily dissolved.
4. This kit can be used for cytokines induced cell proliferation assay, anticarcinogen induced cell cytotoxicity assay or drug induced cell growth inhibition assay.
5. This kit is a one-bottle solution, without premixing any components. All assays can be proceeded in one 96-well plate without wash, cell collecting and additional formazan dissolution. For this, it can be used to detect samples in bulk. In addition, since WST-8 has no toxicity to cells, after coloration, the plate can be read repeatedly, end user have the flexible detection time to choose the optimal one further in this way.   
6. Phenol red and serum do not influence the performance of this kit.
7. This kit can be enough for 500 assays.

 Kit Components
Components Size Storage Instruction
CCK8 Cell Viability Assay Kit 500 T  Store at 4°C in dark for one year, or -20°C in dard for two years


1. Collect the logarithmic phase cells, adjust cell suspension concentration, add 100 μl into each well of the cell cultured plate, adjust the cells density to 1000-10,000 cells per well (Add the sterile PBS into the edged wells of the plate).
2. Seed cells in a 5% CO2 incubator at 37℃ until cells bespread well bottom for one floor (Cells number for each well should be determined by cells’ size and breed speed). Add concentration gradient drug, theoretically, add drug after cells adhere, or 2 hours or half of a day, add 0-10 μl of the drug per well. It is recommend to set 5 wells to analyze in duplicate.
3. Add 10 μl of CCK-8 into each well. (Considering the ratio 1:10). Choose the wells without cells as the control wells.
4. Incubate for 0.5-4 hours, usually 1 hour is enough. The incubation time response to the situation of cell’s type and concentration. End user can try to read the O.D. Values after incubation 0.5 hour, 1 hour, 2 hours and 4 hours respectively to choose the optimal time for future assays.
5. Read O.D. Value at 450nm. If no 450nm filter, 420-480nm filter can be used. Or choose longer than 600nm, like 650nm to do the dual wavelength spectrophotometry assay.

1. If cell culture time is too long, please pay attention to the evaporation issue. Avoid using the outmost wells, use PBS buffer, water or culture medium to replace, or place 96-well plate near by the water in incubator.
2. This kit based on the catalytic reaction of dehydrogenates. If there are too many reducing agents in the testing system, like antioxidant which may interrupt the result, please try to remove them first.
3. Make sure there is no any bubble in each well before reading.
6. Please wear gloves when use the kit.