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What Exactly Is a Cryostat & How Does It Operate?
It is critical to preserve tissue samples and deliver quick findings in clinical pathology, histology, histopathology, and research labs. A cryostat, which employs cryogenic temperatures to freeze and preserve tissues so they may be sectioned using a microtome, can be used to do this.
To create the most effective workflow possible, it's crucial when picking one for your lab that it is the appropriate size, has the proper features, and can segment specimens anyway you need it to.
What Functions Do Cryostats Serve?
Cryostats are used to maintain frozen tissue samples, slice tissue sections thin enough for microscopic inspection, and offer rapid diagnosis for a number of illnesses and medical disorders, including neuromuscular illnesses. They can also be used to study the histochemistry of enzymes. The entire procedure is carried out in a cryogenic environment.
The term "cryogenic temperature" describes a range of temperatures from roughly -150°C (-238°F) to absolute zero (-273°C or -460°F). This temperature range is thought to be where molecular mobility is closest to ceasing entirely. A freezing chamber and cryogenic gas are used to keep the temperature of a cryostat constant.
To reach very low temperatures, cryostats employ a variety of chilling techniques, such as liquid helium or liquid nitrogen baths. A cryostat may also be cooled using argon, oxygen, or nitrogen cryogenic fluids.
How Do Cryostats Function?
Five components make up a cryostat, and they each perform crucial tasks for various types of investigations. These include the blade holder, microtome, specimen holders, freezing chamber or shelf, and anti-roll guides.
Tissues must first be prepared before being studied. When working with tissues, they melt, wrinkle, crack, rip, or otherwise degenerate, cryosectioning is the best option. Optimal cutting temperature (OCT) chemicals, glue, or paraffin must be used to embed the tissue prior to sectioning.
You may use OCT to test your settings before beginning the cutting process to ensure that they are accurate. By doing this, you may learn how to run the equipment without wasting priceless samples.
Freezing Shelf
Sample tissues that are kept and frozen before being sectioned are kept on the freezing shelf.
Due to their proximity to the compressor system, freezing shelves often operate at a temperature that is -10°C below the prescribed cryostat chamber temperature. A Peltier freezing stage, a thermoelectric device that when activated enhances heat diffusion, is a feature of more recent cryostat units.
As a result, the freezing process moves more quickly since the unit has a higher cooling rate. To expedite the procedure and avoid the formation of ice crystals, sample tissues should be tiny and thin (3 to 4mm).
Specimen Holders
Holders for specimens, sometimes known as "chucks," place the frozen specimen on the cryostat microtome for sectioning.
To optimize the gripping ability to retain the samples, chucks are constructed with a crossing grid pattern of precisely cut channels.
Chucks are also composed of stainless steel to be able to endure the strong freezing power and come in a variety of sizes and forms to meet a variety of needs.
Microtome
A cutting edge installed within the cryostat is the microtome. It has a device that moves tissue samples in the direction of a fixed blade, which chops them into minute fragments.
In order to maintain the quality of the sample tissues to be sectioned, older machines include a wheel on the exterior of the chamber where the microtomes may be manually adjusted. Push-button electrical microtome controls are a characteristic of more recent devices.
With the microtome, slicing changes may be performed in micrometers, which is the unit of measurement used to gauge cutting precision. Additionally, vibratomes, which resemble microtomes but employ vibrating blades to cut through tissue samples, are often seen on equipment.
Blade Holder
The microtome is in front of the blade holder. It is either affixed to the cabinet or the base of the microtome. The cutting blade is secured in place by these clamps. The usage of disposable or reusable blades is common.
Temporary Blades
Before needing to be changed, these blades are designed to be used for a specific period of time.
Disposable blades must be clamped while maintaining consistent pressure along the full length of the blade. The climbing pressure will alter if either the front or the rear pressure plate is damaged, which eventually has a detrimental impact on the effectiveness and quality of cryosectioning.
The benefit of using disposable blades is that they don't need to be resharpened, are appropriate for all cryosections and applications, and work with all of the common
Disposable blades have the benefit of not needing to be resharpened, being appropriate for all cryosections and applications, and working with all popular microtome systems, saving you from having to buy numerous blade units for different tasks.
Reusable Steel Blades
An interchangeable steel blade is an option. This is supported by a bar that is sandwiched between two pillars of a typical knife holder. A screw is located at the top of each pillar to hold the blade in place and provide a tight grip.
These blades are constructed with anti-corrosives and either high-quality carbon or tool steel. In comparison to disposable blades, they are therefore more likely to be free of contaminants and less prone to rust. For cutting tissue samples, these blades do require routine sharpening.
Anti-Roll Guides
To avoid curling or rolling portions that are being prepared, they are utilized to remove sections. They have an aluminum frame with glass panes within. In order for the section to slide under, the frame provides a space between the upper surface of the front pressure plate and the glass slides. The section's thickness can be taken into account while adjusting the gap size.
The cooled brush method is used by cryostats without anti-roll guides to collect and aggregate sections. As the section's leading edge approaches the blade edge, a brush drags the section onto the pressure plate and then down the front surface of the blade.
Where can I buy a Cryostat?
If you are looking for a high quality cryostat machine, you can check NanoMagnetics Instruments' Ultra Low Vibration Cryogen Free Cryostat.
Contact us to get a quote for cryostat.