A Glimpse into the History of a Cryostat
A Cryostat is a versatile and high-quality machine that generates low temperatures for tissue sectioning. The word “Cryostat” originates from two separate Greek words “Kryos”, meaning cold, and “stat”, meaning stable. Sir James Dewar, Scottish Physicist, and Chemist are credited for the use of the very first cryostats in the 19th century.
These earlier cryostats – named “Dewar” after the inventor, were just a glimpse into the potential benefits of a cryostat. By the 20th century, the cryostat evolved into more specialized and useful pieces of equipment which had many applications in Science and Engineering. In the healthcare industry, cryostats are used in magnetic resonance imaging (MRI), tissue sectioning, and other pathological applications. There are numerous types of cryostats with varied applications. This article concentrates on the medical applications of a microtome-equipped Cryostat, which have become game-changers in the medical field.
Cryostat-Microtomes in Immunohistochemistry Laboratories
Major 20th-century advances in the field of fluorescently-labeled antibody staining techniques gave rise to the need for cutting fine tissue sections (~5 microns thick). This field of biology is known as Immunohistochemistry (IHC), a technique that uses antibodies to selectively identify antigens (proteins) in tissue sections. A classic example of its application is the biopsy of tissue samples to identify markers of cancer. The only way to achieve fine sections, required in immunohistochemistry applications, is to use a freezing temperature chamber (while sectioning the tissue sample). In the absence of this kind of chamber, the tissue samples are too soft to cut into thin sections. This cold chamber prevents the sample from thawing when the sectioning is in progress and also reduces the destruction of the tissue sample from microorganisms. This cryo-section is absolutely essential when results are expected quickly and the antigenicity of sensitive molecules is to be preserved.
When we consider tissue biopsies for identifying and treating diseases, it is critical (for example) to provide doctors with the quick and correct information for the downstream treatment of patients. The patient samples are sent to the IHC lab for analysis. In an IHC lab, these samples are processed in a cryostat which holds a microtome. Briefly, a microtome is an apparatus that cuts thin tissue sections for analysis. The thin slices created by the cryostat are known as cryo-sections which are then analyzed under the microscope. These ultra-thin sections enable scientists to reach a better conclusion regarding the nature of a disease in a time-efficient manner.
Essential Components of the Cryostat-Microtome
The design of the cryostat depends on its application, in other words, it has to be designed in such a way that the device fitted into the cryostat is fully insulated as well as functional. Although all Cryostat-microtomes follow the same scientific principle, the information provided below uses one of the Cryostat-microtomes from Leica (Leica CM1950) as an example.