A Cryostat is a specialised instrument used in histology and pathology to freeze and cut thin fresh biological tissue for microscopic examination. Similar to a microtome, the cryostat trims the tissue into extremely thin sections however the microtome is located in a chamber that uses extreme temperatures to freeze the tissue sample and keep it frozen within the chamber for ease of sectioning of fresh tissue and faster diagnosis.
11 Features That Make a Good Cryostat
A good Cryostat should have several key features to ensure precision, ease of use, safety, and reliability. Here are the factors that contribute to a high-quality cryostat:
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Temperature Control and Stability
A good cryostat maintains a stable and consistent low temperature, typically between -20°C to -30°C, in order to keep tissue samples frozen during sectioning. However, the ability to adjust temperature in accordance with the type of tissue being sectioned is important as certain tissues may require slightly different temperatures to achieve optimal cutting.
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Precision and Accuracy in Sectioning
A high-quality cryostat, like the Slee MEV and MNT Cryostats, has an integrated microtome with fine adjustment controls for producing thin, precise sections of tissue, typically in the range of 1 to 100 microns. The controls enable precise orientation of the tissue block and make adjustments in 3 dimensions (X,Y,Z axes) to achieve accurate cutting angles.
Using compatible microtome blades for the Cryostat such as the Feather C35 Blades can contribute to the quality of sections produced. The blades should also be durable and extremely sharp in order to make smooth, consistent cuts through frozen tissue without causing damage or distortion to the sample. An anti-roll feature supports creating high-quality sections preventing section from curling as they cut, ensuring they are clean and flat.
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Ease of Use
Slee cryostats have been carefully designed and manufactured to be user-friendly and ergonomic since their founding back in 1954. Digital displays and simple interfaces should allow users to set parameters like temperature, cutting speed, and section thickness quickly and intuitively.
Semi-automatic and automatic functionality offers minimised strain during prolonged use and motorised sectioning reducing manual effort.
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Safety Features
Cryostats should have a locking system to prevent accidental injury from the microtome blade, especially when loading or unloading tissue samples.
The chamber should also be well-insulated to ensure the cold temperature is maintained inside without causing frost buildup on the outside and protecting users.
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Defrost
A good cryostat should have a rapid defrost feature such as automatic defrost to quickly clear the chamber of ice buildup. This allows for easier cleaning and maintenance between uses.
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Cleaning
The internal chamber and surfaces of the cryostat should be made from materials that are easy to clean and disinfect to prevent contamination and ensure proper hygiene during tissue processing.
Some cryostats, including the cryostats manufactured by Slee, come equipped with UV-C light disinfection systems that help maintain sterility by reducing contamination from biological agents. This feature is particularly important when handling infectious or sensitive samples.
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Sample Retention and Handling
Cryostats should offer high-quality specimen holders that can securely hold tissue blocks in place during sectioning, in addition to allowing for multiple samples to be processed simultaneously to increase efficiency, especially in high-throughput labs.
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Cryobar for Tissue Freezing
A cryobar or quick-freezing shelf where tissues can be rapidly frozen to the desired temperature. This is important for preserving tissue morphology, reducing ice crystal formation and providing uniform freezing, to prevent distortion or inconsistent cutting.
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Compatibility with OCT Medium
Most cryostats are used with an OCT (Optimal Cutting Temperature) embedding medium. A good cryostat ensures that the medium and tissue freeze uniformly for easy sectioning.
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Noise and Vibration Control
Cryostats with quiet refrigeration and motorised systems are preferable in busy labs, as they reduce noise pollution and improve the overall work environment. Excessive vibration caused by automation can negatively impact the quality of tissue sections, so a good cryostat is engineered to minimize vibrations during sectioning.
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Low Maintenance and Durability
A good cryostat should be built with high-quality materials to ensure long-term durability and minimal maintenance requirements. The mechanical components, including the microtome and refrigeration system, should be robust and designed to withstand frequent use.
The founding company and origins of the Cryostat, SLEE Medical GmbH, have successfully modified their cryostat over the years to meet the needs of scientists and uphold their well-earned status. SLEE prioritises the original objectives when it comes to any modifications to the Cryostat; ensuring their sole purpose is to cut fast biopsies for the investigation of any abnormal growths or tumours discovered. The microtome inside is capsulated in stainless steel to avoid any interruptions caused by the pollution of condensation or moisture and to prevent downtime from any damage to the machine.
For more information on our range of high-quality Cryostats visit the link below:
Or read more about how the Histology Laboratory at The London Clinic, invested in our MEV+ Cryostat Here.