Guest Editors
Professor Wanderley de Souza, Federal University of Rio de Janeiro, wsouza@biof.ufrj.br
Summary
For many years, scanning electron microscopy (SEM) has been used in the biomedical sciences, primarily to characterize the surfaces of organs, tissues, and cells, providing important information about the three-dimensional organization of such surfaces. Advancements in SEM information have resulted from innovations introduced both in the microscope itself and in the methods of sample preparation. Improvements in SEM resolution have resulted from the introduction of field emission gun, decrease in the diameter of the electron beam that will scan the sample surface, generation of signals from the specimen surface with beams of variable energy, and the development of highly sensitive secondary and backscattered electron detectors. On the other side a novel scanning microscopy technology has emerged recently based on the use of helium ions rather than electrons and designated as Helium Ion Microscopy (HIM). In HIM, the ion emission originates preferentially from only three atoms at the apex of the source and the extracted ions are accelerated down the column of the microscope much in the same fashion as in SEM. But because the gas field ionization source has an ultra-high brightness, a very small beam defining aperture may be used, avoiding spherical and chromatic aberrations and resulting in a greater depth of field and a high resolution. In addition, the He beam does not induce charging, avoiding the need for conductive coating of the samples and thus improving significantly the spatial resolution of the images.
On the other hand, advances has taken place in sample preparation, including the visualization of inner cell structures using methods that expose the inner portions of cells using approaches such as cell cleaving, membrane detachment, freeze-fracture, and the use of detergents that partially or completely remove the plasma membrane and the soluble contents of the cytoplasm.
In this special issue both reviews (invited and submitted) and original papers (submitted) will present an overview as well as new tendencies in the use of these approaches to analyze the structural organization of cells and tissues of different biological models.
Keywords
High Resolution Scanning Electron Microscopy, Helium Ion Microscopy, Cytochemistry, Cell Surface, Cell Wall, Extracellular Matrix, Cytoskeleton, Animal and Vegetal Tissues, Cultured Cells, Protists, Fungi, Bacteria, Microorganism-Host Cell Interaction
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