Entry of dyes can be sensitive to the state of the membrane

Schematic diagram of a living (bacterial) cell with its polarised (charged) membrane. The cytoplamic membrane is represented in red. PI is a cationic dye (propidium iodide) that binds to DNA, and it is not lipid soluble. BOX is lipophilic oxanol dye, negatively ionised, and about 500 MW. Both PI and BOX are fluorescent.


Question: What are the factors affecting staining of the cell by these dyes?