What is a microtome? A microtome is a cutting device or sectioning instrument that is used for cutting biological samples or tissues into thin fine sections. It is a sectioning instrument which allows for the cutting of extremely thin slices of biological materials. The thin slices cut of the whole biological sample (e.g. spleen, intestine, lymph node or liver) is generally known as tissue sections or a section. The process or method used for the preparation of thin sections for biological materials such as liver, intestines, spleen, bone and teeth for microscopy is generally known as microtomy. The microtome is an important piece of instrument or equipment used in both the medical and biological sciences. It is most useful in the histology laboratory where biological samples or tissues from the body of human or animal subjects are sectioned for further biological and/or medical experimentation. Microtomes are an important device in microscopy preparation. This is because the use of the microtome allows for the preparation of biological samples for observation under the microscope. Generally, microtomes use glass, diamonds and steel blades as the major cutting part of the instrument. However, the type of blade to use depends on the type of specimen being sliced as well as on the desired thickness or thinness of the specimen to be sectioned. Steel blades are used to prepare sections of animal or plant tissues for light microscopy histology. To slice sections for light microscopy and to slice very thin sections for electron microscopy, glass knives or blades are used. But for the slicing of some hard biological samples such as teeth, bones and other plant matter for light microscopy and electron microscopy, industrial diamond blades or knives are generally used for these purposes. The thickness or diameter of a section from a biological sample can be between the ranges of 0.05 µm to 100 µm.
Illustration of a microtome
Scientist using the microtome
GENERAL TIPS FOR HANDLING THE MICROTOME
- Always use gloved hands when handling the microtome and biological samples to be sectioned.
- Be careful with the microtome and its sharp blade or knife to avoid cutting yourself.
- Fill the water bath with water, and set the temperature to 40-45o
- Set the diameter or size of the section to be sliced from the whole biological sample.
- Cut few sections first in order to set the cutting range or speed of the microtome.
- Ensure to move the blade slowly while sectioning in order to avoid rough cutting. Rough cutting can cause the sliced tissue to fold, and this can affect the structural integrity of the sectioned tissue.
- Carefully transfer sliced sections onto the water bath using forceps.
- Do not allow sections in water bath for a very long time. The water bath helps to straighten out the cut tissues.
- View cut sections under the microscope to ensure that they are well cut.
- Handle the microtome blade or knife with care to avoid cutting yourself.
- Clean the microtome after use.
- Replace old blades with new ones before doing tissue sectioning.