Using freely diffusing fluorescent dyes like carboxyfluorescein succinimidyl ester (CFSE) allows for the homogenous staining of a whole cell population. The staining is passed on to the daughter cells and by calculating the dilution of CFSE, one can extrapolate the proliferation of cell samples over time.
Nowadays, cell proliferation can also be analyzed with photoswitchable dyes. One example is Kikume, a green-to-red switchable fluorescent protein. The idea is to photoswitch a fluorescent protein at timepoint zero and observe two things over time.
A) The step by step decrease of the photoswitched fluorescent protein.
B) The step by step increase of newly synthesized fluorescent protein.
Looking at ratios of A and B, the proliferation of cells can be analyzed in much more depth.
This has successfully been done by Elena Seiß, part of our pxONE user family.