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Towards more precise definition of conditions for satisfactory deep etching
Author(s) -
Haggis G. H.
Publication year - 1985
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1985.tb04660.x
Subject(s) - propane , thermocouple , jet (fluid) , materials science , allowance (engineering) , composite material , bubble , etching (microfabrication) , mechanics , chemistry , mechanical engineering , physics , layer (electronics) , organic chemistry , engineering
SUMMARY Experiments were carried out to determine whether propane‐jet freezing could be as satisfactory as impact freezing in deep etch work. The material used was the intestinal brush border, previously studied by Heuser and coworkers where the 5–6 nm decoration of actin rootlet filaments, and the fine network of filaments linking these rootlets, provide good criteria by which to judge the quality of the preparation, as regards ice crystal growth and surface contamination. Propane jet freezing was indeed found satisfactory provided appropriate conditions were met (viz thin specimen, fracture near the surface). Variable results were obtained until it was realized that with a Balzers freeze‐etch unit fitted with a rotating specimen table there is a 10–15 min delay (when specimen temperature is reset) between the time the recording thermocouple shows a given temperature to have been obtained and the time the specimen block actually reaches this temperature. Appropriate allowance must be made for this lag to achieve satisfactory deep etch replicas.