Electron microscopes are able to do this because electrons have wavelengths about 100,000 times shorter than photons (light). They can achieve better than 50 picometer resolution and magnifications of up to about 10,000,000x whereas ordinary, non-confocal light microscopes are limited by diffraction to about 200 nanometer resolution and useful magnifications below 2000x.
It uses electrostatic and electromagnetic "lenses" to control the electron beam and focus it to form an image. These lenses operate somewhat similar to the glass lenses of an optical microscope that form a magnified image by focusing light on or through the specimen. Electron microscopes are used to observe a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, metals, and crystals. Industrially, the electron microscope is often used for quality control and failure analysis.
Image: Advances in “virtual nanoscopy” enable the generation of large-scale composite images of biological tissues, as described in The Journal of Cell Biology (JCB) and made accessible through an upgrade to JCB’s JCB DataViewer web application. Users can “zoom in” from a high-resolution, composite image of a zebrafish embryo (top) to detailed images of tiny subcellular structures (bottom). Credit: © Williams et al, 2012
Virtual nanoscopy: Like 'Google Earth' for cell biologists
Just as users of Google Earth can zoom in from space to a view of their own backyard, researchers can now navigate biological tissues from a whole embryo down to its subcellular structures thanks to recent advances in electron microscopy and image processing, as described in The Journal of Cell Biology (JCB). An upgrade to the JCB DataViewer, JCB's browser-based image presentation tool, now also makes these data publicly accessible for exploration and discovery.
The JCB DataViewer is an image hosting and presentation platform for original image data associated with articles published in JCB. Developed in a collaboration between Glencoe Software, Inc. and the Rockefeller University Press, the JCB DataViewer was the first browser-based viewer for multidimensional microscopy image data. It is based on open source software built by the Open Microscopy Environment (OME).
Since the early days of cell biology, electron microscopy has revealed cellular structures in exquisite detail. The technique has always been limited, however, by the fact that it can only capture a tiny portion of the cell in a single image at high resolution, making it difficult for researchers to relate the structures they see to the cell as a whole, let alone to the tissue or organ in which the cell is located. Viewing samples at lower resolution, on the other hand, can reveal the larger picture of a cell or tissue, but researchers then lose the benefit of seeing fine details.
