Fixative, Fixing Agent

A fixative or fixing agent is a chemical substance that is used to preserve and compact tissues for the purpose of their subsequent microscopic examination.

Fixatives are used in histology and cytology to fix cells and tissues. They stop the vital processes of cells and keep the structure of tissues or cells as close to natural as possible.

The most common fixings:

1. Alcohols (ethanol, methanol) are used to fix cells and some tissues.

2. Formaldehyde is the most commonly used fixative and preserves the structure of proteins.

3. Osmium tetroxide - fixes cell membrane lipids.

4. Acetic acid - fixes the structure of chromosomes.

5. Fixer mixtures - for complex fixation of different cellular structures.

The process of fixing tissue using fixatives is called fixation. It is the first stage of histological or cytological sample preparation of samples for microscopy. The correct choice of fixative is extremely important for high-quality histological or cytological examination.

Fixation in microscopy With the development of microsurgery, the need arose to create a variety of micropreparations from processed objects. These preparations can be made by fixing the object with the help of special substances from the moment of killing until its complete death. These substances are called fixatives or, more generally, fixatives. To preserve tissue for further study, such substances must be applied during the fixation procedure.

Types of fixatives Tanning fixative is an organic compound that becomes a tanning compound by depositing sulfur on fabrics. Available in the form of a solution. Its components are water, sulfuric acid, ammonium sulfite or sulfate or glycerin. *Seren (Mercurous sulphide)* and selenium (Sodium selenite) are the best fixatives for thin fabrics. It has blue tones and captures them well. When using the drug, it must be taken into account that it can act destructively or decompose tissues if kept for a long time, although evaporation occurs quite quickly. Therefore, you should be careful with this fastener. When using the drug, you must follow the sequence of action. First, the drug is applied to the tissue, after which it is scraped off with a knife and removed from the bath. Following her

** Fixer, fixing substance**

Introduction

Fixation is one of the key processes in microscopy, which is used to create stable images of tissues and cells. It plays an important role in preserving the details and structures of biological material so that they can be analyzed using a microscope.

The term "fixer" was first used in 1849 by the French botanist Emile Gantesse, who named the substance given to him to fix tissue samples chloroform. This process has become widespread in scientific research and