Introduction
Measuring cell positivity is essential in high content imaging (HCI). With broad applications from measuring gene induction to viral infectivity and clonal analysis, assays scoring cells as positive or negative based on fluorescent intensity levels are used in virtually every high content screening lab.
This Application Note looks at live/dead staining, a common cell positivity assay that quantifies dead cells based on a dye that selectively infiltrates permeable cells but not healthy cells. Membrane permeability provides straightforward assessment of cytotoxicity and apoptosis, with compromised cells exhibiting a characteristically permeant membrane (De Schuter, et al. 2021). Within HCI, assessing cell death and cytotoxicity can both ensure that potential screening hits with a toxicity liability are not carried forward or identify positive hits that cause cell death, in the case of antibiotic and chemotherapeutic screens.