Design and operation of a simple environmental chamber for rapid freezing fixation

Rapid freezing is the most important step in sample preparation for freezefracture and other cryotechniques for electron microscopy. We present the design and operation of a simple environmental chamber coupled to a plungerdriven freezing device that has provided simple and reliable freezing from temperatures and humidities other than ambient. The chamber can be constructed and operated with equipment and techniques common to most electron microscopy labs. Temperature control of0.1C and relative humidities of90% were provided over the range560C. Typical electron micrographs showing well preserved structures comparable to jetfreezing are presented. Copyright1991 WileyLiss, Inc.