How does Neutral red assay enters a cell?

Answer 1

Viable cells will take up the dye by active transport and

incorporate the dye into lysosomes, whereas non-viable

cells will not take up the dye. After the cells have been

allowed to incorporate the dye they are briefly washed

or fixed. The incorporated dye is then liberated from the

cells in an acidified ethanol solution. An increase or

decrease in the number of cells or their physiological

state results in a concomitant change in the amount of

dye incorporated by the cells in the culture. This

indicates the degree of cytotoxicity caused by the test

material.

Answer 2

Neutral red dye freely diffuses across the cell membrane and accumulates in the acidic lysosomes of cells due to its pH-sensitive properties. The dye is absorbed by the cells via endocytosis and is concentrated in the lysosomes, where it becomes protonated and trapped. This accumulation can be quantified as a measure of cell viability or cytotoxicity.