Ultrathin sectioning epoxy resin

After glutaraldehyde fixation (Section 3.1 1 2., step 8), fix the cells further with 1% osmium tetroxide, saturated uranyl acetate, dehydrate in an ascending series of ethanol (70, 90, 100%), and embed in epoxy resin. Ultrathin sections of the block, stained with 1% methanolic uranyl acetate and lead citrate, will reveal immunolabeling on the outer surface of the cells... 

Electron microscopy represents the only direct method that permits to see with our own eyes the interior of a sample with a resolution of a few nanometers. To characterize the texture of hypercrosslinked polystyrenes both transmission and scanning electron microscopy have been appfied. In the former case, ultrathin sections with a thickness of about 600 A were cut firom a sample fixed in epoxy resin, and then directly examined in transmission mode. Alternatively, two-step replicas have been prepared firom the cleavage face. To prepare the repfica the surface was first coated with a collodion film appfied from amyl acetate solution, and then with a carbon—platinum film. Finally, the collodion support was dissolved and the free carbon—platinum repfica examined under a transmission microscope. 

Sectioning Ultrathin sections of LR gold-embedded specimens are cut as for standard (epoxy) electron microscopy resins. Cut sections fresh for any immunolabel-ing experiment. Note Collect sections on nickel grids (300 mesh). Grids may be nsed with or without Formvar coating. 

To observe more detailed axons and myelin sheath regeneration inside the scaffolds, nerve grafts were embedded with Epon 812 epoxy resin, and the mid and distal portions of the specimens were cut into ultrathin sections (50 nm thick) and then viewed and photographed with a Hitachi H7500 transnussion electron microscope (TEM Tokyo, Japan). The thickness of myelin sheath and diameters of myelinated axons were quantified from TEM images using the Image J software. For each specimen, a total of 100-120 random axons were analyzed. 

Brittle crack or craze propagation can be studied by TEM, where the crack or craze was stabilized by filling the notch tip with epoxy resin see Fig. 1.54. A small sample was cut from the material in front of the notch tip and was chemically treated for fixation and staining. Using an ultramicrotome, ultrathin sections are produced from the stained region, containing the crazed zone and the area ahead of the craze (such an area near a craze tip in HOPE is shown in Fig. 2.47 in Part 11). 

Portions of the stained specimens were embedded in an epoxy resin, trimmed to a truncated pyramid shape, and microtomed on a Porter Blum MT-2 ultramicrotome using a diamond knife. Ultrathin sectioning at room temperature to a thickness of 60-80 nm (600-800 A) yielded satisfactory results. Transmission electron micrographs were taken employing a Philips 300 electron microscope. 

Ceynowa performed a TEM study of microtomed Nafion 124 membranes. To increase the electron density contrast, H+ form membranes were converted to the Pb + form using 1.0 M Pb(N03)2 for 60 h. Then, the sample was dehydrated using ethanol solutions, rehydrated in 1,2-epoxypropane, and embedded into epoxy resin. Ultrathin sections were cut to 60-80 nm size. TEM images of the film indicate ion cluster of 3-6 nm in diameter uniformly distributed in the polymer matrix. ... 

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