trypanblått

Trypanblått (trypan blue) is a synthetic vital stain used in microscopy and ophthalmology to differentiate viable from non-viable cells. In Swedish and some contexts, the dye is referred to as trypanblått. It is typically supplied as an aqueous dye solution and is named for its historical use as a stain that penetrates dead cells.

In cell biology, trypan blue exclusion is a standard viability assay. Living cells exclude the dye; dead cells with compromised membranes take up the color and appear blue under standard light microscopy. It is commonly used with hemocytometers to estimate the proportion of viable cells in a suspension.

In ophthalmology, trypan blue is used to stain delicate tissues such as the anterior lens capsule during cataract surgery, helping surgeons visualize the capsule margins for safer capsulorhexis. It can also be used to delineate damaged or devitalized tissue in some corneal applications. The dye is usually applied briefly and then thoroughly rinsed.

Chemical and safety notes: Trypan blue is a synthetic diazo dye. While useful as a stain, it is not benign; it may be cytotoxic at higher exposures and can irritate skin or eyes. Proper handling, ventilation, and disposal per local regulations are advised, and ophthalmic or biological grades should be used for intended procedures.