. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 178 REPORTS FROM THE MBL GENERAL SCIENTIFIC MEETINGS. Figure 1. Wet SEM imaging of dam egg nuclei. IA) Schematic cross-sectional view of the capsule enclosing u sample. The generally rigid capsule (a) is topped by a window, covered by an electron-transparent partition membrane (h). The sample (c) is in close contact with the partition membrane. When placed in the evacuated chamber of a SEM. the sample is maintained in a wet state at atmospheric pressure. The microscopic image is obtained when the scanning electron beam (d) p
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 178 REPORTS FROM THE MBL GENERAL SCIENTIFIC MEETINGS. Figure 1. Wet SEM imaging of dam egg nuclei. IA) Schematic cross-sectional view of the capsule enclosing u sample. The generally rigid capsule (a) is topped by a window, covered by an electron-transparent partition membrane (h). The sample (c) is in close contact with the partition membrane. When placed in the evacuated chamber of a SEM. the sample is maintained in a wet state at atmospheric pressure. The microscopic image is obtained when the scanning electron beam (d) penetrates the partition membrane and interacts with the sample, and hackscattered electrons (BSEt <e) are detected by a BSE detector (/). (B) Clam egg nucleus, adhering to the capsule's partition membrane, was stained with uranyl acetate and imaged in a wet state in an scanning electron microscope (FEl XL-BO ESEM-FEGl Bar = 10 ^m. ICI Clam egg nucleus, adhering in the capsule's partition membrane, labeled with anti-nuclear pore complex antibodies and gold secondarv antibodies, followed h\ xilver enhancement. Bar = 2 (D) Clam egg nucleus, labeled as in (C) but with unti-lamin antibodies. Bar = 2 fun. the imaged layer is limited by the penetration of the beam elec- trons, and is estimated to be 2-3 /urn. Furthermore, the depth can be varied by changing the acceleration voltage of the electron beam (typically within the range of 10-30 keV), yielding three- dimensional information. The method presents some additional beneficial features, some of which were not wholly anticipated. We obtain resolutions between 10-100 nm, an order of magnitude smaller than could he predicted from the volume of interaction of the electron beam with an aqueous sample. Contrast between materials of low atomic number, such as carbon and oxygen, can be readily detected. Thick samples, such as tissue biopsies, can be imaged without thin sectioning: only the top layer of up to 3 /J,m is seen
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
