The MTT assay takes into account its cell viability, through metabolism ( evaluate the flow of NAD (P) - oxidoreductase enzymes), ie the more luminescence, the more viable the cells, or the more metabolically active. But MTT is sensitive to light, meaning if you do not use it carefully, there may be false-negative results.

Trypan blue evaluates cell viability through imbalance of the wall and / or cell membrane. The stained cells are the "non-viable" cells because the dye has been able to penetrate the cells, ie there is some imbalance in the cell barrier. However, over time with trypan blue dye may allow the staining of the cells. In addition, the imbalance of the cellular barriers which allow the penetration of the dye into the cells does not guarantee cell inviability, since there may be cell membrane impairments, but the cells may remain metabolically active.

Further, the MTT assay is qualitative, will allow relative quantification. It needs to be compared to the control to estimate how much more viable each one is. The trypan blue assay is quantitative, giving an "absolute" quantification because, through the cell-to-cell count, it has the estimated number of viable cells.

The ideal is to do the test with both methods, even to ensure the reliability of the results.

Hi,

You can find your answer in following website:

https://www.atcc.org/support/faqs/618b4/Comparison+of+MTT+and+Trypan+Blue-763.aspx

The trypan blue exclusion assay more quantative than the MTT assays.

Trypan blue assay (quantitative) gives cell-to-cell count and estimated number of viable cells but MTT assay (qualitative) will allow relative quantification of cell viability through cellular metabolism