6.1 Dye exclusion assays
The different methods can be used to determine the proportion of viable cells in a cell population. The dye exclusion method is the most straight forward and popular one. This method excludes living cells but does not exclude dead cells. Although it is challenging and time-consuming to conduct the test on a large number of samples, the staining procedure is convenient(Yip and Auersperg, 1972). The dye exclusion method can be used to determine membrane integrity. Eosin, Congo Red, Erythrosine B, and Trypan Blue are among the dyes that have been used(Krause et al., 1984). Trypan blue has been used the most frequently of the dyes described(Aslantürk et al., 2017).
Here in the following issues need to be considered while utilising dye exclusion testing that includes; (a) cells harmed by cytotoxic chemicals may lose membrane integrity over several days, (b)survivor cells can continue to develop during this period & (c) at the end of the growing phase, certain deadly damaged cells may not be labelled as dye since they dissolve too fast.
Dye exclusion tests have distinct benefits for testing chemo sensitivity. They can identify cell viability in non-dividing cells and are quite simple, quick, and use a small number of cells. More research is required to determine the assays’ potential utility in chemo sensitivity evaluation(Lippman, 1983). Next, these dyes are designed for use on cells in suspension rather than monolayer cell cultures, hence monolayer cells should be trypsinized before dye exclusion experiments may be performed(Krause et al., 1984).