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).