نیگروزین

Nigrosin is a dark synthetic dye commonly used in microbiology and histology as a negative stain for visualizing cellular structures and backgrounds.

🏭⚗️ Production
Nigrosin is produced by the sulfonation of a mixture of synthetic black dyes derived from aniline. It is typically supplied as a black powder, which is dissolved in water or ethanol to create staining solutions for laboratory use.

🔬 Properties
Nigrosin appears as a black or dark blue-black powder that forms a deep-colored solution. It is water-soluble and does not penetrate cells, making it ideal for background staining. The dye has a high molecular weight and provides strong contrast under light microscopy. It has a neutral to slightly acidic pH in solution and is stable under normal storage conditions.

🧪 Applications
In microbiology, Nigrosin is widely used in negative staining techniques, especially for visualizing capsules around bacteria and fungi. It stains the background while leaving cells clear and unstained, which enhances contrast. It is also used in certain histological procedures and occasionally in cytology for highlighting structural detail without cell penetration.

⚠️ Safety
Nigrosin should be handled with care. Although it is generally considered low in toxicity, it may cause staining of skin and clothing and mild irritation upon contact with eyes or mucous membranes. Standard laboratory protective equipment such as gloves and safety glasses is recommended during use and preparation.