eozin
Eozin is a general term that can refer to several different classes of synthetic organic dyes, most commonly the eosin dyes. These dyes are characterized by their vibrant pink to red color and their acidic nature, meaning they have an affinity for basic cellular components. Eosin Y, also known as tetrabromofluorescein, is the most widely used eosin dye in histology and microscopy. It is employed as a counterstain in conjunction with hematoxylin, a basic stain. This combination, known as hematoxylin and eosin (H&E) staining, is a fundamental technique for visualizing tissue structure. In an H&E stain, eosin stains the cytoplasm, connective tissue, and red blood cells pink, while hematoxylin stains the cell nuclei blue or purple. The intensity of the eosin stain can vary depending on the concentration of the dye, the duration of staining, and the specific tissue being examined. Beyond histology, eosin dyes have found applications in other fields, including their use as colorants in inks, pencils, and cosmetics. Their ability to impart a strong, visually distinct color is a key factor in their widespread utility.