Electron microscopy metal shadowing

Glenny JR. Rotary metal shadowing for visualizing rod-shaped proteins, in Electron Microscopy in Molecular Biology. A Practical Approach (Sommerville J, Scheer U, eds.), IRL Press, Oxford, UK, 1987, pp. 167-178. 

Electron Microscopy can be used for resolution of smaller objects the practical limit of resolution being a few angstrom units. Electron Microscopy has been used in the study of the morphology of crystalline polymers. The usual techniques of replication, heavy-metal shadowing, and solvent etching are widely used. The direct observation of thin specimens, like polymer single crystals, is also possible and permits the observation of the electron-diffraction pattern of some specimen area, which is invaluable for... 

Figure 15.1 Kleinschmidt metal-shadowing electron microscopy of liposome/DNA complexes. Lipid/DNA complexes were prepared with gradually increasing amounts of DOPE/DOTMA liposomes and a constant amount of DNA (3.5pg/ mL). Liposome/DNA (+/- charge) ratios were 0.2 (A), 0.4 (B), 0.6 (C), 1 (D), and 1.5 (E). The scale bar represents 0.5 pm. This figure was reproduced with permission from Gershon et al. (1993).

Kleinschmidt metal-shadowing electron microscopy of liposome/DNA complexes 276... 

Insoluble surface films can be studied by electron microscopy. The films are transferred from the substrate on to a collodion support and shadow-cast by a beam of metal atoms directed at an angle a (about 15°) to the surface (Figure 4.21). If the width x of the uncoated region is measured, the thickness of the film, x tan a, can be calculated for example, a /i-C36H73COOH film has been shown to be about 5 nm thick - i.e. consistent with a vertically orientated monomolecular layer. The technique has also been used for following the state of the surface as a film is compressed. 

Ghadially EN, Lock CJL, Lalonde JMA, Ghadially R. Platinosomes produced in synovial membrane by platinum coordination complexes. Virchows Arch., B, Cell Pathol. 1981 35 123-131. Beretta GL, Righetti SC, Lombardi L, Zunino F, Perego P. Electron microscopy analysis of early localization of cisplatin in ovarian carcinoma cells. Ultrastruct. Pathol. 2002 26 331-334. Ruben GC. Ultrathin (Inm) vertically shadowed platinum-carbon replicas for imaging individual molecules in freeze-etched biological DNA and material science metal and plastic specimens. J. Electron. Microsc. Tech. 1989 13 335-354. 

Transmission electron microscopy Is also used to obtain Information about the shapes of purified viruses, fibers, enzymes, and other subcellular particles by using a technique, called metal shadowing. In which a thin layer of metal, such... 

Transmission electron microscopy (TEM) Negative staining and metal shadowing Chemical and structural information for liquid foods and emulsions... 

Shadow casting The coating of electron microscopy specimens with a heavy metal, such as gold or palladium, to create a three-dimensional effect. 

The lamellar thickness, L, is an important parameter for polymer crystals and is usually measured by low angle x-ray diffraction (LAXS) or by electron microscopy on heavy metal shadowed specimens grown from dilute solution. For polymer crystals... 

The main technique is transmission electron microscopy. Single crystals deposited on a carbon-coated metal grid can be viewed after shadowing with a heavy metal using the bright field technique (Fig. 7.23). 

Electron microscopy contributed to the study of virus structure with two techniques (a) heavy-metal shadowing, in which heavy metal vapors are deposited upon a grid with the virus particles this reveals structural details where the metal atoms have been deposited, (b) Negative staining, in which the virus suspension is treated with phospho-tungstate, an electron-dense material, which fills the empty spaces and crevices of the particle. 

Transmission electron microscopy has proved to be the most effective technique for the characterization of the particle size distribution in emulsions. A dilute solution cast on a carbon film and metal shadowed shows an agglomerate of latex particles in a commonly encountered drying pattern where the shadowing method shows the particles are flat and obviously not separate or discrete (Fig. 5.114A). The area in Fig. 5.114B would also be difficult to use for particle size measurement, whereas in Fig. 

Figure 5.152. Transmission electron microscopy micrographs of sonicated fibrils, shadowed with metal in order to provide information about the three dimensional structure of (A) Vectran and (B) Kevlar fibers, illustrate the tape-like structure. A range of fibrils are observed that are long and are seen to fibrillate into finer fibrils. Twisting and a cotton-like flat, twisted, or tape-like fibril structure is observed. The aramid fiber (B) is shown to fibrillate into units less than 10 nm wide. (From Sawyer et al. [632] used with permission.)...

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