Difference Between Microtome and Ultramicrotomy

The key difference between microtome and ultramicrotomy is that thin slices of specimens derived from microtome can be observed either by light microscopy or electron microscopy while extremely thin slices of specimens derived from ultramicrotomy can be observed by electron microscopy.

Specimen preparation is a vital technique in microscopy. The preparation of tissues for microscopy is mainly done by cutting very thin slices. There are different techniques to cut pieces of specimens. Microtome is a piece of equipment that cuts very thin slices. Ultramicrotomy is a type of microtome that cuts extremely thin slices of plant and animal tissues. Selection of the technique depends on how thin the specimen should be for observation.

CONTENTS

1. Overview and Key Difference
2. What is Microtome 
3. What is Ultramicrotomy
4. Similarities Between Microtome and Ultramicrotomy
5. Side by Side Comparison – Microtome vs Ultramicrotomy in Tabular Form
6. Summary

What is Microtome?

A microtome is a tool that cuts thin slices of specimens for microscopy. They mainly help in cutting tissue and organ specimens from organisms to be observed under the microscope. Therefore, microtome is important in the process of specimen preparation. It is possible to observe the specimens prepared using microtome by either light microscopy or electron microscopy. Microtomy cuts materials into very thin slices ranging from 50 nanometers to 100 micrometres thickness.

Microtome uses various tools to cut the thin sections of material. The type of tool depends on the type of material. The blades for cutting are made of steel, glass or diamond. The tool selection also depends on the thickness of the specimen required for the downstream processes. Steel blades cut plant and animal tissues for histological light microscope observations. Glass blades slice thin sections for electron microscopy. Diamond blades are the most versatile type. It cuts hard substances such as teeth and bone matter for both light and electron microscopy. Furthermore, diamond blades are useful in cutting gems.

What is Ultramicrotomy?

Ultramicrotomy is a branch of microtomy. The technique cuts specimens into extremely thin sections that can only be identified by electron microscopy. Moreover, transmission electron microscopy facilitates the observing of specimens that result from the ultramicrotomy. Usually, biological specimen preparation takes place through ultramicrotomy. However, even metal and plastic specimens can also undergo ultramicrotomy.

Ultramicrotomy facilitates the preparation of specimens that vary in its thickness from 50 nanometers to 100 nanometers. Basically, it uses a diamond knife. Moreover, we have to view the specimen from an electron microscope prior to the cutting process. We have to mark the area for slicing before slicing takes place. The specimens sliced using ultramicrotomy is mounted on to metal beads for the observation and downstream processing. It is also possible to freeze these specimens for future usage. The technique is complex and costly in comparison to the microtomy technique.

What are the Similarities Between Microtome and Ultramicrotomy?

• Microtome and ultramicrotomy are two techniques we use for specimen preparation for microscopy.
• Both are able to slice specimens such as biological and non-biological samples into thin sections.
• They may use electron microscopy for observation.
• Moreover, both microtome and ultramicrotome use blades made from diamonds for slicing the specimens.

What is the Difference Between Microtome and Ultramicrotomy?

Ultramicrotomy is a subdivision of microtomy, which is a technique of splicing materials for microscopy. The key difference between microtomy and ultramicrotomy relies on the type of microscopy they use to observe the specimen. It is possible to observe slices derived from microtome by both light and electron microscopy; however, we can only observe the slices derived from ultramicrotomy through electron microscopy.

Moreover, the types of blade used in the two techniques also vary. Microtome uses steel, glass or diamond blades while ultramicrotomy uses diamond and glass blades. Thus, it is also a difference between microtome and ultramicrotomy. Besides, a further difference between microtome and ultramicrotomy is that while microtomy cuts thin sections, ultramicrotomy cuts extremely thin sections of specimens.

Summary – Microtome vs Ultramicrotomy

The key difference between microtome and ultramicrotomy is their ability to cut different sliced specimens. In this regard, microtome cuts thin slices ranging in the size of 50 nanometers to 100 micrometres while ultramicrotome slices specimens ranging from 50 nanometers to 100 nanometers. Thus, it is possible to observe slices derived from microtome by both light and electron microscopy; however, we can only observe the slices derived from ultramicrotomy through electron microscopy.

Reference:

1. Newman, Sanford B. ADVANCES AND APPLICATIONS OF ULTRAMICROTOMY. ProQuest LLC (2015), Available here.

Image Courtesy

1. “Tissue processing – Microtome is used to cut a ribbon of 5-micron-thick sections from the paraffin block” By Ed Uthman – originally posted to Flickr as Tissue Processing 09.jpg (CC BY-SA 2.0) via Commons Wikimedia
2. “Cryo Ultramicrotome” By MST –  (Copyrighted free use) via Commons Wikimedia