AAT Bioquest

What are the most commonly used biological stains?

Posted March 9, 2023


The most commonly used biological dyes include: DAPI, carmine, crystal violet, fuchsin, hematoxylin, iodine, methylene blue, ethidium bromide, malachite green, safranin, rhodamine, and coomassie blue. DAPI is a blue fluorescent nuclear stain that is excited by UV light, and can be utilized in live or fixed cells. Crystal violet stains cell walls purple when used with a mordant, and this stain is used in Gram staining. Carmine colors glycogen red, and is used in cosmetics as well. Ethidium bromide stains unhealthy cells in late apoptosis fluorescent red-orange. Fushin is utilized for staining collagen, mitochondria, or smooth muscle. Safranin is a nuclear stain that may be used as a counterstain or to stain collagen yellow. Malachite green is a blue-green counterstain to stain spores, and has antifungal properties as well. Rhodamine is a protein-specific fluorescent stain utilized in fluorescent microscopy. Coomassie blue stains proteins bright blue and is typically used in gel electrophoresis. Iodine is used as a starch indicator, and when in solution, starch and iodine turn a dark blue color. Hematoxylin is a nuclear stain that, with mordant, nuclei colors blue-violet or brown.      

Additional resources

Ethidium Bromide

DAPI [4,6-Diamidino-2-phenylindole, dihydrochloride] *CAS 28718-90-3*

MycoLight™ Rapid Fluorescence Gram-Positive Bacteria Staining Kit