9/28/96
I have a question regarding cryoultramicrotomy of moisture-
sensitive polymers for TEM. My usual technique for cryo sectioning is to
collect sections with a wire loop and sucrose solution, transfer the
sections to a TEM grid, and float the grid, section-side down, on water so
as so to dissolve the remaining sucrose. I now want to section ionomers,
to which I would like to minimize exposure to water. Could anyone suggest
a method for collecting sections without water?
Thanks in advance,
Len Radzilowski
Dept. of Materials Science & Engin.
M.I.T.
Cambridge, MA 02139
radzil@elt
The following reference outlines a method that we have found very
useful and easy to use.
Tsuji, S. et al., 1992, Cryoultramicrotomy: Electrostatic transfer of
dry ultrathin frozen sections grids applied to the central nervous
system, Arch. Histol. Cytol. 55: 423-428.
Regards,
Dr. Gerald J. Little,
The Neuroscience Group,
Discipline of Anatomy,
Faculty of Medicine and Health Sciences,
The University of Newcastle, Callaghan,
New South Wales, Australia, 2308.
Ph (61 49) 21 5618
Fax (61 49) 21 8667
Email ANGJL@Medicine.Newcastle.edu.au
I have no experience in your particular method, but for many
years we have cut dry sections at ambient temperature of
resin embedded material for x-ray microanalysis. This
entails manipulating the sections onto carbon-coated
formvar-filmed grids with the old eyelash probe. Once on the
formvar, they can be gently tacked down with the probe,
normally at the corners and along the edges. They are then
carbon coated again for STEM work. Maybe you could try
something similar. Manual dexterity is required!
Regards - Keith Ryan
KPR@wpo.nerc.ac.uk
We usually collect our (polymer) cryo-sections without water. We use a
thin nylon filament attached to a round wooden stick holder to manipulate
the sections and to place them directly onto folding grids. The grids are
right behind the diamond knife, so they are also in the cryo-chamber. It
takes a bit of practice, but after a while the technique works just fine.
I do encounter some curling or folding of the sections, but use of
antistatic devices seems to alleviate this.
Jordi Marti
MartiJ@MTOMP201.Research.Allied.com