What is a microtome and why do you need it?

Fun Fact

The first microtome suitable for sectioning animal tissues was constructed in 1848, with the popular Cambridge Rocker (1885), Minot (1886), and sled microtomes (1910) manufactured later. Kerosene wax for infiltration and support during cutting was introduced during the mid-1800s. Different laboratory chemicals were investigated for use as fixatives. Formalin, used today, was first used in 1893.

In the everyday routine within a laboratory, microscopic substances and samples are very common. Most of the time, it is necessary to cut some of the samples into extremely thin slices of material, known as sections. In order to prepare a sample and to make those types of cuts, you must have a microtome, a very essential device in the field of microscopy. The use of the microtome array allows the preparation of samples for observation under transmitted light or electron radiation.

Microtomy is a method for the preparation of thin sections for materials such as bones, minerals and teeth, and an alternative to electro-polishing and ion milling. Microtome sections can be made thin enough to cut a human hair across its width.

Among the applications of microtome, there is the traditional Histology technique, where tissues are hardened by replacing water with kerosene. Moreover, it can be found in the frozen section, procedure where water-rich tissues are hardened by freezing and cut in frozen state with a freezing microtome or microtome-cryostat. In addition, there is the Electron Microscopy technique. On the other hand, there is the technique of botanical microtomy, where hard materials such as wood, bone and leather require a sledge microtome. In addition, there is spectroscopy and fluorescence microscopy.

Before purchasing a microtome array, you should familiarize yourself with its main parts. First, there is the base plate or stage of the microtome, where the rails secure the blade. Second, there is the base of the blade holder. Then, there is the knife holder. Then, there is the cassette clamp or block holder, which holds the kerosene block in place. In addition, there is the coarse handwheel and finally there is the micron adjustment.

The rotary microtome is the most common

It is used for cutting embedded kerosene blocks. In addition, it can be used for cryostat frozen sections and in cases with embedded resins, e.g., renal biopsies LR tissue embedded with white resin and marrows embedded in methyl methacrylate (MMA). Sectioning is produced by the movement of the microtome head containing a block across the blade.

The vibrating microtome uses a vibrating blade, which facilitates cutting of the sample. This microtome uses less pressure than would be required with a stationary blade and is often used for difficult biological samples such as nerve tissue, brain and spinal cord. The stability of the instrument reduces mechanical forces on the tissue sample to ensure retention of high quality viable cells.

Cryostat microtomes are rotating microtomes that cut samples (cryosectioning) that have been frozen in a liquid nitrogen chamber. The reduction of the temperature inside this chamber increases the hardness of the sample, allowing the preparation of sections with a very specific thickness. Finally, ultra microtomes are common for preparing samples with extremely thin sections. Typically, these very thin sections are used with transmission electron microscopy (TEM), serial face scanning electron microscopy (SBFSEM) and light optical microscopy.

When a microtome is used for section cutting, the sections are of uniform thickness. They can be obtained at any desired thickness (10 or 15 or 20 n, etc.). The sections are not oblique. The entire tissue can be retained in sections, which is particularly necessary for studying the development of a plant organ. However, sectioning the microtomes is a long and laborious process. In free-hand sections, the thickness of the section cannot be regulated; it can be thick or thin, as well as oblique. In addition, not all the material in the sections can be obtained, as the defective ones must be discarded. Take a look at our available microtomes Visit our website HERE