I am having problems growing a specie of bacteria and have been looking for a good way of differentiating between dead and living cells. Having explored some bacterial techniques (e.g. PI/DAPI), I discovered we were missing the filter to see them and was therefore on the look-out for alternatives. Here, I am exploring staining with Trypan Blue. Although these are mamalian cells, what is useful is that living cells show up bright white while those dead are blue. The grid seen under the microscope can be used to count those dead and alive....as seen above most are living.