A temperature-jump device for time-resolved cryo-transmission electron microscopy

✍ Scribed by Dr. M. H. Chestnut; D. P. Siegel; J. L. Burns; Y. Talmon

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 854 KB
• Volume: 20
• Category: Article
• ISSN: 1059-910X
• DOI: 10.1002/jemt.1070200110

✦ Synopsis

We describe a temperature-jump device that permits time-resolved studies of thin cryo-transmission electron microscopy specimens. The specimen is rapidly heated to induce a change in microstructure just prior to cryo-fixation. The apparatus consists of a xenon arc lamp equipped with a shutter controlled by timing circuitry, used in conjunction with a n environmental specimen preparation chamber. The specimen is heated by exposure to focused light from the lamp, and then plunged into cryogen. Using a thermocouple constructed from an electron microscope grid, we show that temperature jumps of 30-60 K are achieved with exposure times of 150-450 milliseconds. Micrographs of dimyristoyl phosphatidylcholine (DMPC) vesicles and n-docosane films, subjected to these exposures, show that the specimens are still at least 20-30 K above their initial temperature when they contact the cryogen. This method could be applied to a variety of biological and chemical systems which undergo structural changes activated by a rise in temperature.