From Freezing to Fixing: The Essential Role of Cryostats

What Are Cryostats?

Cryostats  are specialist pieces of equipment that maintain subzero conditions while sectioning to prepare frozen tissue samples for microscopic examination. Similar to microtomes, both are used to section tissues, however, cryostats are designed specifically for frozen tissue sections and producing rapid results. Each sectioning instrument serves a unique purpose in histology, pathology, and research. But why are cryostats used and why is cryo-sectioning so much faster?

 

 

The History of Cryostats

Where the need to analyse samples has to be accurate yet rapid, the Cryostat remains the stand out piece of equipment for real-time pathology. Founded in the early 1950s, Slee Medical is well-known for it’s high-precision products. Company founder, Heinrich Slee alongside Prof. Anthony Pearse, pioneered the development of the cryostat for use in histology and pathology. Over the last half century, we have seen how this instrument has revolutionised intraoperative diagnostics and research workflows.

1958: Kenneth Slee and Prof. Anthony Pearse develop the first freezing microtome

 

 

 

How Do Cryostats Work?

The common practice of paraffin tissue processing can take over 24 hours. Where time is limited, cryostats are used to speed up this process, rapidly freezing tissue to create ‘frozen sections’.

 

Initial Freezing

To create stability and enable sectioning the sample may need to be embedded. In cryostats, tissue is embedded in a freezing medium, such as Optimal Cutting Temperature (OCT) compound.

Once immersed in embedding medium, the tissue is placed on a metal chuck and rapidly frozen.

 

Frozen State

Slee’s range of cryostats maintain temperatures between 0°C down to -35°C to meet specific sample requirements. A consistent low temperature keeps the tissue frozen and preserves its morphology during sectioning.

 

Sectioning

Once frozen, the tissue is mounted on the specimen holder and a microtome within the cryostat is used to cut thin sections. An anti-roll plate or brush ensures each cut section lays flat and is easy to pick up to be transferred to a microscope slide. It’s important to note that any tools, including brushes, should be kept within the cryostat to ensure they remain cool.

 

Staining

Frozen sections on slides can be quickly stained (eg. Hematoxylin and Eosin (H&E)), ready for examination under a microscope.

 

 

 

Top 5 Benefits of Using Cryostats

 

Preservation

Rapid freezing helps to preserve cellular details. It is also effective at preserving antibody activities and enzymes.

Swift Diagnostics

Frozen tissue can be sectioned directly inside the cryostat, this allows pathologists to obtain sections for analysis within minutes of freezing the sample.

Immediate Decisions

In both clinical and research settings, immediate access to sections minimises delays in experiments and diagnoses. Cryostat-prepared sections are essential for intraoperative consultations, where surgeons need real-time pathology results to aid immediate surgical decisions.

Convenience

Unlike traditional paraffin processing, which involves multiple time-consuming steps from fixation to sectioning, cryostat processing follows a more concise pathway, saving hours. Additionally, rapid staining techniques for cryostat sections further accelerate the process.

Efficiency

A number of cryostats, including the Slee MNT Cryostat, feature automated functions that speed up operations and reduce manual handling. With cryostats able to process multiple samples simultaneously, throughput is improved in busy labs.

 

Cryo-sectioning vs Paraffin Processing 

Streamlining the Process

 

Cryostats are effective tools for speeding up tissue processing, significantly reducing turnaround times and making them invaluable in clinical and research environments where speed and accuracy are critical.

Our Slee Cryostats stand for reliability, precision, safety and convenience. To find out more about our full Slee range please get in touch.