A High Speed Microtome for the Electron Microscope

Abstract

Two forms of a high speed type of microtome are described which are able to cut cross sections to the thinness required for electron microscopic study (0.1 to 0.8 micron, depending on the material). Techniques of microtome operation are suggested together with a few methods of sample preparation and subsequent section treatment, namely, collecting, selecting, and mounting. Embedding materials which sublime readily are described; these have been used successfully with this high speed microtome to support many types of materials. These volatile embedding materials have the advantage that they eliminate the difficulties that on some occasions arise with the use of solvents in the process of solvent extraction of embedding materials, such as Carbowax and paraffin, from the sections. A number of photographs are shown of the high speed microtome as well as electron micrographs of a few sections produced by the instrument. These pictures of rubber, rayon, Lucite, block Nylon, and animal tissue indicate some of the fields of application of the microtome and demonstrate the effectiveness of the necessary auxiliary techniques for it, particularly sample hardening and embedding, and section collecting and mounting.

Correlation of some mechanical properties of embedding resins with their behaviour in microtomy

“…In ultramicrotomy, however, the "chips" are the goal in the form of ultrathin sections. After unsuccessful attempts to produce them at high and very high speeds (Fullam and Gessler, 1946;O'Brien and McKinley, 1943), only much slower speeds (around 0.5-5 mdsec) have led to routinely successful ultrathin sections (Danon and Kellenberger, 1950;Fernandez-Moran, 1957;Porter and Blum, 1953;Sitte, 1955;Sjostrand, 1954). Consequently, all commercially available microtomes, discussed by Sitte and Neumann (1983), are based on low-speed sectioning with glass or diamond knives.…”

Advances in Graphene‐Based Liquid Cell Electron Microscopy: Working Principles, Opportunities, and Challenges

“…Preserving fine cellular structures is crucial for high‐resolution electron microscopy of biological specimens. This often results in time‐consuming sample preparation or the need for expensive cryo‐TEM instruments . Graphene sandwiching of biological samples not only preserves fine cellular structures and retains the water content of samples, but also mitigates the destructive beam‐induced damage by dissipating electrons and charges to relatively far distances.…”

Albert Claude and the Beginnings of Biological Electron Microscopy

“…The solutions initially worked out for microtomy proper consisted in a reduction-by a variety of mechanical devices--of the rate of advance of the specimen towards the knife in the microtomcs then available for light microscopy (5); or in devices (7) or maneuvers (5) that produced wedge-shaped sections, 1 since it was assumed that their tapering edge would be thin enough for electron microscopy. Another favored formula was the use of a special microtome provided with a blade rotating at high speed while the specimen was advancing slowly against the knife (9,10). The ratio of the specimen to blade movements could be adjusted so as to give sections as thin as N0.1 .…”

“…A possible solution still available was microtomy and Claude was already experimenting in this direction before the publication of the paper on chicken tumor cells. The group at the Interchemical Laboratory was developing at the time a high speed microtome (10) which was used to cut thin sections from rubber, acrylic resins, and nylon. The group was also experimenting with eutectic mixtures as embedding FIOURE 1 Electron micrograph of a "fibroblast-like cell" published as Fig.…”