Accurate Measurement of the Thickness of Ultrathin Sections by Interference Microscopy
نویسندگان
چکیده
In quantitative electron microscopy, a knowledge of the thickness (0) of the sections is often required . For example, when objects smaller than 0 (e .g . ribosomes) are counted in sections, 0 must be known in order that the observed numbers may be related to the unit volume of the section . Even when comparatively large structures are submitted to morphometric analysis, the section thickness cannot be disregarded if the size of the object is of the order of a few times 0 (5) . Several techniques have been used to measure section thickness, but they suffer important limitations, which can be of three kinds : (a) Their accuracy is not satisfactory, at least for 0 ranging from 30 to 60 nm. In published interferometric methods, the accuracy is not better than 10% (2, 7). (b) Thickness measurement and electron microscopic examination cannot be performed on the same section, mounted on the usual microscopy grids (6) . (c) The method is restricted to special cases, for example when certain folds are present in the section (4) or when standard objects are embedded together with the material (3) . The interferometric method proposed here obviates the limitations (b) and (c) and its accuracy is better than 1 nm . We used a Zeiss Standard GFL POL microscope, equipped with a Jamin-Lebedeff
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عنوان ژورنال:
- The Journal of Cell Biology
دوره 49 شماره
صفحات -
تاریخ انتشار 1971