A microtome is a device that slices organic or inorganic samples into strips called sections. Microtome blades generally consist of diamond rock, glass or metal, allowing for thin sections of uniform size.
Laboratory technicians specializing in histology or pathology mount these sections on slides and examine them with a microscope. This enables clinical lab staff to section patient samples for biopsies and other diagnostic procedures while allowing researchers to section and analyze samples from lab rats, plants and other organisms.
6 Types of Microtomes
There are numerous different types of microtomes, each designed to address unique requirements. Here's an overview of the most common models so you can make the best selection for your needs.
1. Rotary Microtome
Rotary microtomes are the most common option for laboratories. These devices section paraffin-embedded tissue samples within the range of 0.5 to 60 micrometers (µm). These machines have a simple design, consisting of a weighted handwheel, sample chuck and blade assembly.
Microtomy happens through the following steps:
- The lab technician spins the handwheel clockwise.
- With each revolution, the sample will connect with the blade.
- Once the layer is divided into a uniform section, it retracts on the upward stroke to prevent it from rubbing against the side of the blade. This ensures minimal damage to the sample.
Many rotary microtomes comprise motorized sectioning and foot pedals. These allow the user to step on a pedal and conduct automatic sectioning, saving the user effort and ensuring consistent sections.
Want to learn more about rotary microtomes? Here's a video explaining some of their common features.
2. Sliding Microtome
Laboratory technicians favor sliding or sledge microtomes for their versatility. While their primary purpose is to section the same type of samples as rotary microtomes, they are also effective in sectioning hard materials like wood — providing you have a proper blade. A further consideration of sliding microtomes is their varying size range. Many are about the same size as a rotary microtome, but in industrial environments, they can be large enough to section things a few feet wide. Sections are typically between 1µm and 60µm.
As the name implies, the blade of a sliding microtome is mounted on a slide. It moves down the slide to the fixed sample holder, sectioning off a layer with each stroke. This simple design lends itself to longevity and easy maintenance.
3. Saw Microtome
Saw microtomes are ideal for sectioning hard, brittle samples like bone, teeth, and wood. As such, they're used in biological and environmental research labs, as well as in forensic procedures.
With saw microtomes, samples are mounted against a spinning blade recessed within the unit. Some have diamond blades to ensure clean sections for even the hardest samples. As the blade spins, a low-pressure water jet continuously pours water on the edge of the blade to prevent it from overheating.
Saw microtomes produce the thickest sections of any microtome. However, their design does not allow for sections thinner than 30µm.
Here's a video from Simon Fraser University that shows the entire microtomy process with a Leica SP1600 saw microtome.
4. Vibrating Microtome
The purpose of vibrating microtomes is to section soft, fresh samples that are free of wax. The microtome and sample combo ensures the cell morphology remains intact. Sample examples include brain, nerve and spinal cord tissue. The vibration allows for the sample to be sectioned with less pressure than it would normally require, ultimately minimizing the chances of fracture.
Fresh samples sectioned with vibrating microtomes are typically over 30µm thick. Fixed samples are over 10µm thick.
5. Laser Microtome
Laser microtomes are the only options that offer non-contact microtomy — this is vital for applications that require the sample's cell morphology to remain unaltered. Additionally, laser microtomy doesn't need any sample prep beforehand. Samples can be cut “in their native state.” This saves labs precious time and resources.
Because they don't use razor blades, laser microtomes can slice virtually any type of sample from bone to soft tissue.
6. Ultramicrotome
Ultramicrotomes were designed to produce sections for transmission electron microscopy (TEM). In order for TEM to work, sections must be slimmer than 150nm — much thinner than the 30µm sections produced by most other microtomes.
Interested in learning more? Here's a video demonstrating an ultramicrotome.
Shop Used Microtomes at New Life Scientific
A microtome is essential for many clinical and research applications. Ensure you make the best choice for your laboratory by carefully considering the various available options.
New Life Scientific specializes in used laboratory equipment, enabling you to equip your workspace with the best technology at a fraction of the price. Our specialized team offers expert insights, while our generous 90-day warranty gives you further peace of mind. Explore our current range of used microtomes today, or get in touch with us for personalized assistance!
