An Oscillating Cryo-knife Reduces Cutting-induced Deformation of Vitreous Ultrathin Sections
Wiley open access: In the context of developing a new cryo-knife for producing of vitreous ultrathin sections without deformation or other cutting artefacts, a Leica EM PACT instrument was used for high-pressure freezing of the samples. The inventor of cryo-freezing, Jacques Dubochet, who received this year’s Nobel Prize in Chemistry, was involved in this work.
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Al-Arnoudi, J. Dubochet, H. Gnaegi, W. Lüthi, D. Studer; An oscillating cryo-knife reduces cutting-induced deformation of vitreous ultrathin sections; J Microsc. 2003 Oct;212(Pt 1):26-33. DOI:10.1046/j.1365-2818.2003.01244.x
A new oscillating cryo-knife for producing uncompressed vitreous sections is introduced. The knife is a modified cryo diamond knife that is driven by a piezo translator. Optimal setting for the oscillation was found to be in the inaudible frequency range of 20–25 kHz. Yeast cells and polystyrene spheres were used as model systems to describe compression in the vitreous sections. We found that compression could be reduced by a factor of about 2 when the knife was oscillating. When the oscillator was turned off, sections were compressed by 40–45%. However, only 15–25% compression was obtained when the knife was oscillating. In some cases completely uncompressed sections of yeast cells were produced. It was also found that the amount of compression depends on the specimen itself and on its embedding medium. With the results shown here, we demonstrate that the oscillating knife can produce high-quality vitreous sections with minimum cutting artefacts.