Freezing in Histological Technique

Freezing in Histological Technique: Features and Applications

In histological technology, freezing is one of the most common methods for preparing tissue preparations. This method is especially valuable for studies that require preserving as many biochemical and morphological characteristics of tissues as possible. Freezing allows you to quickly cool pieces of tissue, which allows you to preserve the maximum amount of biologically active substances in them.

The method of preparing histological preparations by freezing is carried out using solid carbon dioxide. This method is one of the most effective and allows you to obtain high-quality drugs that do not require additional processing.

The freezing process begins with rapid cooling of tissue pieces in solid carbon dioxide. In this case, ice forms, which fixes the tissue and preserves its structure. The specimen is then cut into very thin sections using a microtome. Thin sections are placed on a glass slide, after which the preparation is stained with special dyes.

The advantages of freezing in histological techniques are obvious. Firstly, this method makes it possible to preserve the biochemical and morphological characteristics of tissues to the maximum extent possible. Secondly, freezing provides high image clarity, which is important for diagnostic studies. Thirdly, this method makes it possible to obtain high-quality drugs without additional chemical treatments, which reduces the time and costs of research.

However, it should be noted that freezing is not always the optimal method for preparing tissue preparations. Some types of tissue may be sensitive to freezing and may change their structure and properties. In addition, freezing may result in artifacts that may affect test results.

Thus, freezing is an important method in histological techniques, which allows preserving the biochemical and morphological characteristics of tissues to the maximum extent. However, before using this method, the characteristics of the tissues being studied and the possible limitations of the method should be taken into account.

Histological technique is a method for studying the tissue of the human body. To obtain high-quality samples, it is necessary to carry out a process such as freezing biological materials. What is freezing?

Freezing is not just stopping molecules and nerves for a second. When an object's temperature drops below freezing (+3.8 Celsius), the water in the cells freezes, making the tissue harder. To effectively spin the tissue cubes from frozen water back into liquid water, you need to expose them to temperatures above freezing. To do this, freezing must occur very quickly, for which suspension in solid carbon dioxide (CO2) is used.

For preparation, medical tissue pieces are stored in a special liquid that contains a cryoprotectant (ethanol) and a buffer (sodium lauryl sulfate). They are placed in CO2, which is filled with a material with a very large surface area. The solution is then released into the air, where it releases its weight of CO2 into the surrounding layers of CO2 - the small bubbles of CO2 expand, cooling the surface and immediately plunging it into a liquid state. This speeds up the freezing process and distributes the CO2 evenly throughout the tissue cube. Columns of dry ice float upon contact with tiny ionogens within the tissue cube (which cause the tissue to freeze faster upon contact).