The working principles of these assays vary but generally involve distinguishing between living and dead cells based on specific cellular properties:
- MTT Assay: Cells are incubated with MTT reagent. Metabolically active cells convert MTT to formazan, which is solubilized and measured. - ATP Assay: Cells are lysed to release ATP, which reacts with luciferase to produce light. The emitted luminescence is measured. - Trypan Blue Exclusion: Cells are mixed with trypan blue dye and then counted under a microscope. Only dead cells absorb the dye. - Clonogenic Assay: Cells are plated at low density and allowed to grow. Colonies are stained and counted after several days or weeks. - Flow Cytometry: Cells are stained with fluorescent dyes that bind to DNA or other cellular components. A flow cytometer analyzes the fluorescence intensity to determine cell viability.
