Nigrosin stain, 10% w/v is used as staining solution for negative staining. ... Nigrosin consists of a suspension of fine particles of carbon. These form a dark background, against which capsules are clearly seen as a result of displacement of the carbon particles.
Eosin-Nigrosin is a staining technique that assesses the vitality of a sperm sample when the initial motility is less than 25 %. Nigrosin increases the contrast between the background and sperm heads, making sperm easier to visualize. Eosin stains only the dead sperm, turning them a dark pink, whereas live sperm appears white. This staining technique must be performed immediately after motility is assessed using sperm from the same semen sample. Stained slides can be stored for reevaluation and quality control purposes.
Nigrosin stain, 10% w/v is used as staining solution for negative staining. Negative staining method permits visualization of the usually transparent and unstainable capsule of many organisms, most importantly Cryptococcus neoformans.
