Comparison of preparation techniques of mixed samples (fungi–helminth eggs) for scanning electron microscopy by critical point drying

2006 ◽  
Vol 99 (4) ◽  
pp. 455-458 ◽  
Author(s):  
P. L. Sarmiento ◽  
María L. Ciarmela ◽  
P. Sánchez Thevenet ◽  
M. C. Minvielle ◽  
J. A. Basualdo
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.


Author(s):  
Arthur L. Cohen ◽  
Gerald E. Garner

The surface forms and structures of animal cells have been strikingly preserved for scanning electron microscopy by freeze-drying and by critical point drying both by the method with CO2 used as the transitional fluid and the later procedure which uses a fluorocarbon (Freon 13) as a medium for the transition from the liquid to the gaseous environment. Freeze-drying is often prolonged (5-12 hours as compared with an hour or less by the critical point method) and in our experience with mold cultures on agar, the substrate shrivels and cracks and hyphal filaments are distorted.Despite, and possibly because of a flexible but inelastic cell wall, plant cells often show greater distortion than do animal cells after evaporative drying or replacement dehydration for mixrotechnical work. The animal cell membrane can contract more or less uniformly on drying - as shown by the numerous micrographs of well-preserved erythrocytes, while plant cell walls often crumple. The many scanning electron micrographs of partially collapsed pollen grains bear witness to this fact.


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