MTS assay

CellTiter 96® AQueous One Solution Cell Proliferation assay (MTS assay)
It is a colorimetric method for determining the number of viable cells in proliferation or cytotoxicity assays.

MTS tetrazolium compound i.e. (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) is bioreduced by cells intro a coloured formazan product, which is soluble in tissue culture medium – decreasing toxicity to cells seen with an insoluble product (MTT assay). This conversion is accomplished by NADPH or NADH produced by dehydrogenase enzymes in metabolically active cells
Phenazine methosulfate (PMS), an electron-coupling reagent, is combined with MTS reagent to form a stable solution due to PMS’s enhanced stability.
The quantitiy of formazan product is directly proportional to the number of viable cells in the culture as measured by the absorbance at 490nm.

For the MTS assay, 5 x 103 cells per well were cultured in 96-well plates and treated with cytotoxic compounds (What I am studying) for 48 and 72 hours respectively. After incubation for specified times at 37°C in a humidified incubator, 25µL of MTS reagent was added to each well and further incubated for 2-4 hours. Absorbance was measured at 490 nm on a micro plate reader.

Advantages
• Fast – Eliminates solubilization of formazan crystals before absorbance reading and MTS is more efficiently bioreduced compared to MTT
• Safe – Requires no volatile (easily evaporated at normal temperatures) solvent to solubilize formazan product

Li Yinliang Alex 0704894E
TG02 Group 8
6 September 2009