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You must have a microtome

Curious fact

The first microtome suitable for sectioning animal tissues was constructed in 1848, with the popular Cambridge Rocker (1885), Minot (1886), and sledge microtomes (1910) manufactured later. Paraffin wax for infiltration and support during sectioning was introduced during the mid1800s. Different laboratory chemicals were investigated for use as fixatives. Formalin, widely used today, was first used in 1893.

In the everyday routine inside a laboratory, microscopic substances and samples are very common. Most of the time it is necessary to cut some of the samples in 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 microscopy field. Microtome series use 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 section a human hair across its breadth.

Between microtome’s applications, you can find the traditional Histology Technique where tissues are hardened by replacing water with paraffin. Moreover, you can find them in frozen section procedure where water-rich tissues are hardened by freezing and cut in the frozen state with a freezing microtome or microtome-cryostat. In addition, there is the Electron Microscopy Technique. Moreover, there is theBotanical Microtomy Technique where hard materials like wood, bone and leather require a sledge microtome. In addition, there is spectroscopy and Fluorescence microscopy.

Before you purchase a microtome series, you should get familiar with its major parts. First, there is the microtome base plate or stage, where rails secure the knife. Second, there is the knife holder base. Then, there is the knife holder. In addition, there is the cassette clamp or block holder, which hold the paraffin block in place. Moreover, there is the coarse hand wheel and finally there is the micron adjustment.

The rotary microtome
is the most common microtome type

It is used for sectioning of Paraffin embedded blocks. Also, can be used for frozen sections in cryostat and for resin-embedded cases, for example renal biopsies LR white resin embedded tissue and Bone marrows embedded in methyl methacrylate (MMA). Sectioning occurs by movement of microtome head containing block across blade.

There is another microtome tip

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

Cryostat microtomes are rotary microtomes that slice samples (cryosectioning) that have been frozen in a liquid nitrogen chamber. Reducing the temperature inside this chamber increases the sample’s hardness, 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 cuts are used with transmission electron microscopy (TEM), serial block-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.). Sections are not oblique. The entire tissue can be retained in sections — this is particularly necessary for studying the development of a plant organ. However, microtome sectioning is a long-drawn and laborious process. In free hand sections, the thickness of the section cannot be regulated; it may be thick or thin, as also oblique. Moreover, the entire material cannot be obtained in sections, as the defective sections have to be thrown away.

You can find different kinds of  microtomes  in our catalog.

This article was published on Monday 04 September, 2017.

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