Scanning+Electron+Microscope


 * =Who invented the microscope? When and where was the it invented? =

The scanning electron microscope was invented by Manfred Von Ardenne in 1937. At the time, he was a scientist working under the german flag. = = =How does is work? What is its magnification power? =

The microscope works producing a focused beam of electrons that interact with atoms within the sample. This process produces various signals that contain various information about the sample's surface and composition. Before the sample can be scanned, it is first coated with a heavy metal. After the sample is prepared, a focused beam of electrons is used to scan across the surface of the specimen. The electrons acre scattered or emitted from the surface of the sample, and are collected to produce a 3 dimensional image up to 500,000 times greater than the origional. = = =Which cell parts where discovered using this microscope? = = = Because the first official invention the scanning electron microscope was recorded in 1937, and not used in the field of biology until the late 1940's, most of the known cell organelles had been previously discovered. Furthermore, the resolution of the microscope was relatively poor when compared to other modern microscopes. Also, the way that the scanning electron microscope works is by scattering and collecting electrons of the surface of the specimen. This works well for producing a three-dimensional image of the whole cell, but cannot necessarily produce images of cell organelles within the cell.

=What are the limitations of this microscope (what can't it do?)? = = = The electron scanning microscope works by scanning the surface of a specimen and collecting the scattered electrons, this process produces a three-dimensional image. However, the beam of electrons never passes through the specimen, so its internal workings cannot be examined. Furthermore, the resolution of the scanning electron microscope is about 10nm which limits its uses to examining whole cells rather than cell organelles or macromolecules. The maximum magnification achieved by a typical scanning electron microscope is about 500,000 times greater than its actual size.

=Who currently uses this type of microscope (which types of occupations or organizations?)? = = = Electron microscopy is considered (by most today) to be an old technique, yet it is still being used in the clinical field (such as viral and pathogenesis studies.) In the diagnostic setting, it is particularly valuable in the surveillance of emerging diseases. In the research arena, through the usage of the microscope, scientists have demonstrated how viral structural components "fit together, attach to cells, assimilate during replication, and associate with the cellular machinery during replication and egression" (Goldsmith, Cynthia S., and Sara E. Miller). These studies provide a new understanding in the clinical field for treatment and vaccine strategies. = = =Analogy =

The scanning electron microscope is to cells as the huba telescope is to space. ||

Works Cited
“Scanning Electron Microscopy.” How Does Scanning Electron Microscopy Work?, www.nanoscience.com/technology/sem-technology/.

Goldsmith, Cynthia S., and Sara E. Miller. “Modern Uses of Electron Microscopy for Detection of Viruses.” Clinical Microbiology Reviews, American Society for Microbiology (ASM), Oct. 2009, www.ncbi.nlm.nih.gov/pmc/articles/PMC2772359/.

Cooper, Geoffrey M. “Tools of Cell Biology.” The Cell: A Molecular Approach. 2nd Edition., U.S. National Library of Medicine, 1 Jan. 1970, www.ncbi.nlm.nih.gov/books/NBK9941/.

<span style="font-family: Times New Roman,Times,serif;">“Scanning Electron Microscope - Advantages and Disadvantages in Imaging.”MicroscopeMaster, www.microscopemaster.com/scanning-electron-microscope.html.