The Leica UCT is an ultramicrotome which is used to section samples which have been
embedded in epoxy plastics or low viscosity plastics (LR Gold, LR White, Spurr, araldite,
methacrylate, Lowicryl, etc.) or similar media. Sectioning can be performed with either
glass or diamond knives.
Glass knives are used to cut semi-thin sections (0.5-1 mm thick) that are mounted
on glass slides and stained with toluidine blue for observation by standard light
microscopy. Semi-thin sections are valuable on their own as they reveal fine cytological
details not always visible on standard (4-10 mm thick) histological sections. Semi-thin
sections are also used to determine which parts of the sample will be thin sectioned
with a diamond knife.
Diamond knives are used to cut ultra-thin sections 50 to 100 nm in thickness. These
sections are mounted on 3 mm in diameter copper grids (50-150 mesh size), stained
with uranium and lead and observed with a transmission electron microscope. Diamond
knives can be purchased from electron microscopy supply companies with cutting edges
from 1 to 6 mm.