Freeze‐Fracturing of Biological Material With A New Specimen Table

Abstract

The freeze-fracturing of various biological material is described with the aid of a modified Balzers specimen table. The advantages of this table are easier and faster handling of the specimens and a better thermal contact between the specimen and the cold stage.

A new inexpensive specimen carrier for freeze‐fracturing

“…The new specimen carriers can therefore be used with commercially available specimen tables, e.g. the new specimen table manufactured by Balzers AG and described by Nickel et al (1978).…”

“…From left to right: reversed position to show a carrier coded with black colour in the groove of the U-profile, in normal position without specimen, in normal position with a drop of suspension (2 1.1). (b) Commercially available specimen table (Nickel et al, 1978) with standard and new specimen carriers introduced between the two teeth of the springs, which are then released so that they clamp the carriers firmly. 7 SCa, standard gold specimen carriers: the data are calculated for 100% gold, atomic weight 196.9665, carrier weight 585 mg (mean weight of disc-shaped, flat specimen carriers made of 95% gold and 5% nickel, top surface scratched for better adhesion of the frozen specimens).…”

Design and application of a freeze‐fracture stage with a cleaver device for Balzers ‘freeze‐etching’ apparatus

“…The use of a microtome mechanism, fitted with a cooled blade for fracturing frozen tissue at a specified temperature of 173 K, though suitable for some applications, often partly damages the specimens, and is particularly difficult to apply to tough tissues such as skin. Large areas of replica which are completely devoid of useful information result, as the knife produces score marks on the sample surface (Staehelin & Bertaud, 1971;Nickel et al, 1978;Bohler, 1979;Willison & Rowe, 1980). Koehler (1968) and Staehelin & Bertaud (1971) also emphasized contamination by water vapour produced by the sublimation of ice at the interface (ice to metal of the knife), and additional contamination by sublimation from small ice chips which are scattered on freshly revealed fracture faces, or which remain attached to the edge of the knife.…”