Supporting freeze-etch specimens with “Lexan” while dissolving biological remains in acids
Russell L. Steere, Eric F. Erbe · Proceedings annual meeting Electron Microscopy Society of America · 1983
In studies of cold hardiness in plants it became important to have freezeetch specimens of woody poplar stems (populus sp.) and to fracture them at −75°C. The most satisfactory approach involved the use of two pairs of precooled pliars to break off small, 1 to 2 mm thick, pieces of the frozen stems. Glycerol (40%) was frozen at −75°C onto the upper grooved surface of a modified specimen cap. A small pool of the glycerol was melted with a metal probe and a fractured piece of specimen was placed on the pool which refroze very rapidly with no glycerol contacting the upper fracture surface. The specimen cap was transferred to the cold stage of a Denton Freeze-etch module. Excess frost was removed by holding specimen temperature at −100°C for the 10 min required to obtain a vacuum of 2 × 10−7 Torr and to cool the shroud to −196°C. The specimens were then held at −90°C for an additional 10 min for further etching.