6.2.2 Methyl ThiazolylSulfophenyl (MTS) assay
The mitochondrial enzymes used in the MTS assay (5-(3-carboxymethoxyphenyl)-2-(4,5-dimethyl-thiazoly)-3-(4-sulfophenyl) tetrazolium, inner salt assay) transform a tetrazolium salt into a coloured formazan. The amount of formazan produced can be measured using a colorimetric technique at 492 nm and is proportional to the number of live cells in the culture. This test is efficient in terms of simplicity, accuracy, and speedy toxicity indication. The MTS assay is an in vitro cytotoxicity test that is quick, sensitive, affordable, and selective. It can therefore be used for on-site toxicological assessments. One of the limitations of the assay is that the absorbance reported at 492 nm is influenced by the incubation time, cell type, and cell counts, as well as the ratio of MTS detection reagents to cells in culture. According to previous research reports, incubation time and absorbance are linearly correlated for up to 5 hours, with 1-3 hours being the ideal duration. [19].