Cryostats are indispensable devices in the fields of pathology and histology. These machines allow laboratories to section frozen tissues for microscopy applications rapidly. With a cryostat, a physician can make a fast diagnosis, or a researcher can analyze cells more quickly and accelerate the development of a new treatment.

If you're seeking a new cryostat for your lab, it's essential to select a reliable device with adequate temperature control and ultra-thin sectioning capabilities. The ideal cryostat has all the features you need to offer fast results and create an efficient workflow.

Before you buy a cryostat, you need to know what to look for and how these features might be applied in your lab. In this post, we'll explore the different types of cryostats, their parts and their applications. We'll also help you decide whether you should buy a new or refurbished cryostat. If you have any questions about choosing a cryostat that meets your budget and specifications, please contact us at Mercedes Scientific. We're here to help you make the right choice.

What Is a Cryostat?

In general, a cryostat is any container that holds devices or liquids at a very low temperature. In the histology and pathology fields, a cryostat refers to an upright, deep-freeze chamber that houses a microtome. A microtome is a specialized cutting instrument used to slice tissue samples into very thin segments. Lab technicians typically use cryostat microtomes to cut frozen tissue blocks into sections ranging from 8 to 15 microns (µm) in thickness. Users can access the chamber and microtome through a glass window and door.

Cryostats use various refrigeration methods and are insulated to high standards to ensure they easily maintain the desired temperatures. A cryostat machine can keep temperatures at a low level, usually minus 15 to 30 degrees Celsius.

To use a cryostat, a lab technician must first prepare the tissue by applying an embedding medium and freezing the sample, which can be done in various ways. They might freeze the tissue in isopentane, for example, or liquid nitrogen. The goal is to freeze the tissue as quickly as possible and prevent ice crystal formation. The overall purpose of freezing the tissue is to make the sample hard and much easier to cut.

After the lab technician prepares the sample, it can be mounted onto a specimen holder and placed on the cryostat's freeze shelf. This allows the sample to stabilize at the cryostat's chamber temperature. Finally, the researcher can attach the specimen holder onto the microtome. Typically, they'll then control the microtome using a hand-wheel located on the outside of the cryostat. The microtome blade will cut the frozen tissue block into thin sections, which can then be placed onto microscope slides for examination. The entire process may only take 10 minutes, allowing for fast analysis.

Who Invented Cryostats?

Sir James Dewar is credited with inventing the first performing cryostat in 1897. In the early days, cryostats were used to contain liquified gases. Dewar used double-walled metal-plated glass containers to hold liquified nitrogen. Today, cryostats that hold cryogenic fluids are called dewars.

Different Types of Cryostats

Various types of cryostats are available with different specifications, depending on the manufacturer. To choose the right type of cryostat, you need to consider your application requirements, budget and the tissue type you'll be handling. Here are the types of cryostats to consider:

1. Single Compressor

A single compressor cryostat uses one compressor to cool the chamber and the freeze shelf. With one compressor, you cannot control the freeze shelf's temperature separately because it is part of the chamber's refrigeration system. Clinical laboratories might choose a cryostat with a single compressor to section biopsies quickly. In this example, lab technicians can leave the window to the freezer chamber closed for most of the sectioning process. One compressor may be adequate for cooling both the chamber and the specimen holder.

2. Dual Compressor

A dual compressor cryostat uses two compressors. One compressor controls the chamber's temperature, allowing the user to maintain the desired temperature as they cut tissue. The second compressor chills the freeze shelf separately. Dual compressor systems can cool down faster than single compressor cryostats and reach lower chamber temperatures. Also, a dual compressor system helps prevent interrupted refrigeration if one of the compressors fail.

A dual compressor cryostat may be ideal for research laboratories since technicians might leave the window open for long periods to collect many frozen samples.

3. Rotary

Rotary cryostats are equipped with a manual microtome. This type of cryostat is often found in laboratories and features a hand-wheel, which allows the user to move the frozen tissue block toward the microtome's blade and control the cutting action. Labs might prefer rotary cryostats as an economical option. Rotary cryostats also provide extra control of the cutting process.

4. Motorized

Cryostats are available with semi-automatic and automatic rotary microtomes. A semi-automatic microtome has one motor to advance the fine or coarse feed hand-wheel. A fully automatic microtome uses two motors to drive the fine and coarse feed hand-wheels. To advance the tissue block, the lab technician uses a foot pedal or digital keypad.

Motorized cryostats reduce the need for repetitive motions related to hand-wheels and increase productivity as a result. According to Indiana University, a histology laboratory technician might turn a microtome wheel a thousand times in a day. Therefore, a motorized cryostat may be the preferred choice for better ergonomics and prolonged use.

Cryostat Parts and Functions

Before you buy a cryostat for your lab, it's essential to learn about its basic parts and functions so you know what to look for. Here's an overview of a cryostat's fundamental components:

1. Microtome

The microtome is the cutting instrument mounted inside the cryostat. The microtome holds a very sharp blade, which is used to section the frozen tissue block. Lab technicians can adjust the microtome in micrometers to get precisely cut tissue samples. Although rotary microtomes are commonly used to section frozen tissues, cryostats can hold just about any microtome type, as long as the cutting instrument is rust-proof.

2. Blade Holder

The microtome's blade holder is located in front of the microtome and may be fixed to the microtome's base or the cryostat cabinet. It consists of several parts, including:

• Blade clamp: This holds the blade.
• Knife tilt: This part adjusts the blade's angle.
• Face plate: This directs the tissue sections away from the blade and toward the microtome operator.

The type of blade you choose for your cryostat depends on the microtome and the material you're sectioning. For general applications, you can choose between a fixed or disposable blade. Disposable blades have become the go-to choice for labs because they provide an extremely sharp edge with every use. You can find universal disposable blades to fit any microtome. However, you might choose a fixed blade if you need to cut through incredibly hard materials.

3. Specimen Holder

The specimen holder, also called a chuck, is a metal mounting base that holds the frozen tissue block. Specimen holders come in various shapes and sizes to match a range of embedding tasks. For example, they might feature concentric rings or a grid pattern to grip the specimen and the embedding material used.

4. Anti-Roll Guide

An anti-roll guide is a square or rectangular glass plate held inside a metal frame. The guide rests on top of the blade holder. During cutting, the tissue sections go between the anti-roll guide and the face plate. This keeps the sections flat and prevents them from curling or rolling.

Without an anti-roll guide, the lab technician might use the cooled brush technique to collect tissue sections. This technique involves using a fine artist's brush to guide the sections over the blade holder.

5. Freeze Shelf

The freeze shelf is the area located next to the microtome. Since the freeze shelf is typically located next to the compressor system, it's usually minus 10 degrees Celsius lower than the chamber temperature, on average. Some new cryostats incorporate a Peltier stage with the freeze shelf. A Peltier stage is a device that boosts the diffusion of heat away from the tissue sample, accelerating the freezing process.

Cryostat Applications

Cryostats are often found in pathology laboratories and research centers. Lab technicians may use them to make a rapid diagnosis, such as diagnosing a lesion. Unlike regular microtomes, which require lab workers to dehydrate and embed samples in paraffin, cryostats produce tissue samples much faster for microscopic examination.

Although cryostats can be used in a range of fields, common applications include:

• Pathology: Pathologists use cryostats for sectioning frozen biopsy tissue. By using a cryostat, doctors can quickly analyze tissues and look for cancer or other diseases.
• Histology: Histology cryostats are used to slice plant or animal tissues under cryogenic conditions, allowing researchers to study cell anatomy.
• Dermatology: Cryostats are a critical instrument for sectioning frozen specimen during Mohs surgery. After using the cryostat, doctors can evaluate tissues and look for cancer cells. They can quickly determine if they need to remove additional tissue.

Choosing a Cryostat for Your Lab

The type of cryostat you need largely depends on the tissues you section and your price requirements. Overall, you'll need to consider the following factors:

• Specifications: Before you purchase a cryostat, check its specifications and make sure it fits your needs. For example, consider the materials you need to cut and ensure the cryostat's technical specifications align with the thickness you need and specimen size. Also, think about the cryostat's size and if you have adequate space for the unit.
• Usability: The cryostat you choose should be safe and easy to operate and maintain. Consider elements that may aid productivity, such as an ergonomic design and automatic features.
• Brand: Research the cryostat's brand and model before you decide to buy. Any piece of lab equipment you buy should come from a brand with a solid reputation.
• Budget: Review your budget and consider how much you can afford to spend on a cryostat. Prices vary depending on a cryostat's manufacturer and features. For example, a motorized cryostat typically costs more than a manual one. You'll also want to compare distributors to find the best price for your needs. If you have any questions about our cryostat prices or would like more details, feel free to ask us at Mercedes Scientific.

New vs. Refurbished Cryostats

When you're ready to buy a cryostat, you may wonder if you should purchase a new or refurbished machine. In general, the word "refurbished" means that a piece of equipment has been inspected, repaired, tested and cleaned. In other words, a refurbished cryostat comes in like-new condition, performs according to the manufacturer's specifications and carries minimal risk. Refurbished cryostats are typically more affordable than new ones and may be the preferred option for budget-conscious labs. If you wish to purchase a refurbished cryostat, it's critical to buy from a dependable supplier. You'll also want to buy from a supplier who offers warranties on refurbished cryostats.

You may want to purchase a new cryostat if you want a specific model or feature and have room in your budget for new equipment. A benefit of buying a new cryostat is knowing that no one used it before.

Buying Affordable Cryostats

It is possible to buy an affordable, high-quality cryostat from a reputable supplier. Prepare to research the supplier and ask questions so you can feel confident in your purchasing decision. Find out the following information:

• How long the company has been in business
• If the company has a good reputation for customer service and after-sales support
• If the company offers warranties

Overall, you'll want to choose a supplier who's willing to guide you before, during and after the buying process. They should treat you as a business partner and not just another customer.

Cryostats for Sale at Mercedes Scientific

Whether you plan to buy a new or refurbished cryostat, you're about to make a big decision. Like any piece of lab equipment, cryostats are an investment, so it's essential to make the right choice. At Mercedes Scientific, we're ready to help you find a cryostat to fit your lab's budget and suit your application needs.

Founded in 1991, Mercedes Scientific is a customer-focused medical and laboratory equipment distributor. We offer a large inventory of new and refurbished cryostats at competitive prices to meet your specifications. If you're looking for cryostats from names like Histo-Line Laboratories or Leica Biosystems or have questions about any of our products, please contact us or request pricing — we'll be happy to help you.