What is the Difference Between Freezing Microtome and Cryostat?

The main difference between a freezing microtome and a cryostat lies in the temperature range used for freezing the tissue and the purpose of the instruments.

A freezing microtome is used to make thick sections of frozen tissues, with a thickness of several micrometers. It operates at a temperature range of -60 °C to 0 °C and consists of a deep cooled platform where the sample is placed and frozen. The platform is raised after each section to correspond with the selected thickness. The freezing microtome is often used for the study of cellular ultrastructure, which requires fast and deep freezing, for example, by liquid nitrogen.

On the other hand, a cryostat is designed to obtain thin (1-10 mm in thickness) sections of tissue at low temperatures, typically between -20 to -30 °C. Unlike a standard microtome, which operates at room temperature, the cryostat maintains the cryogenic temperature of samples or devices. Cryostat sectioning offers two main advantages over standard histology microtome sectioning: shorter turnaround time from fixation to tissue section, and better preservation of protein antigenicity. However, a disadvantage of cryostat sectioning is that ice crystals may form during the cryofixation process, which can distort the tissue.

In summary, freezing microtomes are used for making thicker sections of frozen tissues at slightly higher temperatures, while cryostats are designed for obtaining thinner sections at lower temperatures.