Does 7-AAD stain necrotic cells?

Yes, 7-AAD (7-amino-actinomycin D) is highly efficient for staining necrotic cells.

7-AAD is a fluorescent, membrane-impermeant dye with a strong affinity for double-stranded DNA. It intercalates selectively at GC-rich regions of DNA. Because of its inability to pass through intact cell membranes, 7-AAD cannot stain live cells. It can only stain late apoptotic cells and necrotic cells that have lost their cell membrane integrity and are permeable to the dye. This feature makes 7-AAD very useful as a cell viability dye. It allows researchers to clearly distinguish between live and necrotic cells in flow cytometry.