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Available variants and Uses of Eosin

Author: Lillian Tong
by Lillian Tong
Posted: Jan 08, 2023

Eosin is a fluorescent yellow anthracene dye, usually used for histological staining. This article briefly introduces its properties and uses.

What is Eosin

Eosin is a fluorescent, yellow anthracene dye or red dye, formed by the action of bromine and fluorescein, which combines with the salts of acidophilic compounds containing positive charges. In order to understand the general histological structure of tissues, the combination of Eosin and alum hematoxylin staining is the most appropriate. This staining solution can examine the cytoplasm, collagen and muscle fibers under a microscope.


Heinrich Caro, the inventor of Ehong, decided to name the compound Eos after her childhood friend Anna Peters. It comes from Eosin, the Greek meaning of dawn, and is also the name of the Greek goddess of dawn.

Available variants

When it comes to variants of Eosin, there are two very closely related compounds in histology. The available and most commonly used variants are:

Eosin Y: It is also called yellowish Eosin, Acid Red 87, C.I. 45380, Bromine Eosin, Bromofluoresconic acid, etc. It is a derivative of tetrabromofluorescein.

Eosin B is also called the slightly blue Eosin Blue, Acid Red 91, C.I. 45400, Saffron, Eosin, or Imperial Red. Eosin B is a derivative of fluorescein in the form of dibromodinitro.

Each dye can be used interchangeably, and the selection is driven by preference and tradition.

How does Eosin staining work?

In addition to being used for more than a century, Eosin staining is still necessary to identify various tissue types and morphological changes. In addition, it is compatible with a variety of fixatives and has many characteristics of cytoplasm, nucleus and extracellular matrix. Reverse dye with Eosin to get red. The intensity of Eosin depends on individuals. "Eosin Y" is usually widely used as Eosin, and the name is used worldwide.

Histology Application

Eosin is used in combination with other dyes such as hematoxylin and methylene blue as a dye for different histological purposes. According to the dyes used, we can divide them into the following two dyeing technologies:

Hematoxylin and Eosin staining

Hematoxylin and Eosin (H&E) staining usually uses Eosin as a counter staining. Histologically, H&E staining is one of the most commonly used methods. The tissues stained with hematoxylin and Eosin showed pink orange cytoplasm and dark purple or blue nucleus. In addition, Eosin can also detect strong red blood cells. In histological examination, Eosin Y at a concentration of 0.5-1% was used to stain cytoplasm, red blood cells, collagen and muscle fibers.

H&E staining is the main staining method in histology, because it can be completed quickly and cheaply. The way of staining tissues reveals a large number of microscopic anatomical structures and can be used to identify various histopathological diseases.

About the Author

ECHEMI is a chemical supply chain service company headquartered in Hong Kong, providing chemical raw materials supply, research and analysis, marketing, distribution, logistics, E-commerce and after-sales services.

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Author: Lillian Tong

Lillian Tong

Member since: Jun 26, 2022
Published articles: 25

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