WST-8 is a water-soluble tetrazolium salt can be reduced by NADH in good yields at neutral pHs in the presence of 1-methoxy PMS to produce the corresponding formazan dye that absorbs at 460 nm.

Store in dark at 4 ℃.

General protocol for cck-8 assay:

1. Prepare cck-8 working solution: dissolve WST-8 and 1-mPMS (CSN17270) in ddH₂O to a final concentration of 500μM and 20μM, respectively.

2. Please ensure that the volume of the culture medium is just 100μL in every well.

Note: For WST-8 can be reduced, make sure that there is no reductant or oxidant in the culture media. If you add compound during cell culture, please wash every well for 2 times with PBS and add fresh culture medium before detection.

3. Add 100μL of cck-8 working solution into every well of 96-well plate.

4. Gently shake the plate to mix the solution well.

5. Incubate the plate in a CO₂ incubator at 37°C for 0.5-4h. After incubation, the colour of the solution should turn to orange.

6. Read the plate at 450 nm with a reference wavelength at 650 nm with an M-UVmax microplate reader.{{Ishiyama M, Miyazono Y, Sasamoto K, Ohkura Y, Ueno K. A highly water-soluble disulfonated tetrazolium salt as a chromogenic indica

WST-8 is a water-soluble tetrazolium salt can be reduced by NADH in good yields at neutral pHs in the presence of 1-methoxy PMS to produce the corresponding formazan dye that absorbs at 460 nm. The orange colored formazan produced from WST-8 is soluble to water at concentrations higher than 100mM. Thus, it makes WST-8 widely used in cell proliferation assays, called cck-8 cell vitality assay.

[1] Ishiyama M, Miyazono Y, Sasamoto K, Ohkura Y, Ueno K. A highly water-soluble disulfonated tetrazolium salt as a chromogenic indicator for NADH as well as cell viability. Talanta. 1997 Jul;44(7):1299-305. doi: 10.1016/s0039-9140(97)00017-9. PMID: 18966866.