Electron Microscopy & EDX

Microscopy is the scientific study of using a microscope to magnify objects that are too small to be seen with the naked eye. There are different types of microscopy, which are light microscopy, electron microscopy, and probe microscopy. The three different techniques allow scientists to analyze cell tissue, cell structures, and organ systems (Assumpção Pereira-da-Silva & Ferri, 2017).

 Electron microscopes were first invented in the early 1900s, when the first electromagnetic lens was created. Ernest Ruska is credited with inventing the first electron microscope, which led to his winning a Nobel Prize (Edwards, 2012). The primary use of electron microscopy is to capture detailed images of organic and non-organic specimens. This allows scientists to study tissue cells, organelles, and macromolecular complexes.  Electron microscopy uses electrons as the source of illuminating radiation. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) are the two primary types of electron microscopes. Transition electron microscopy allows electrons to move through thin sections of the specimen to create an image. This process allows for a clear view of a cell. Scanning electron microscopy works by releasing secondary electrons from the surface of a specimen to determine the elemental composition of a biological sample. Scanning electron microscopes are renowned for their high magnification and depth of field, enabling the creation of high-resolution images. SEM  depicts images of the cell surface as well as the whole organism that cannot be displayed in the transmission electron microscope. Scanning electron microscopes enable particle counting and size determination by scanning the specimen’s surface with electrons in a raster pattern (UMass Chan Medical School, 2021).

EDX stands for energy dispersive X-ray spectroscopy. EDX, an analytical technique, is used in conjunction with scanning electron microscopes to determine and estimate the elements present in a sample. EDX determines the elemental composition of a biological sample by depicting an elemental outline in different colors. Energy-dispersive X-ray spectroscopy utilizes color codes to distinguish sections of an element sample, enabling researchers or scientists to identify abnormalities within the sample. EDX can also be used to study specific sections that are not clearly visible using a transmission electron microscope or a scanning electron microscope. Energy-dispersive X-ray spectroscopy enables a better understanding of the samples’ formation conditions and macroscopic properties. EDX works similarly to the scanning electron microscope and transmission electron microscope because they all use electron beams to illuminate radiation. Energy-dispersive X-ray spectroscopy operates by calculating the energy and intensity of the radiation when used in conjunction with a scanning electron microscope. The X-ray image is composed of the electron beam penetrating the inner shell of an atom, creating an electron vacancy. The higher energy outer shell balances the inner shell, which results in the outer shell becoming a lower level shell because it lost energy.  Energy-dispersive X-ray spectroscopy utilizes elemental mapping, which colors a sample to map out structures and elements on its surface. The colors shown in Elemental mapping represent the concentration of a particular component at each point. Bright colors represent higher concentration, while dark colors represent lower concentration of elements (Bruker, n.d.).

References

Assumpção Pereira-da-Silva & Ferri (2017). Microscopy. Science Direct. Retrieved October 5, 2025, from https://www.sciencedirect.com/topics/materials-science/microscopy

Edwards, S. (2012, January 19). The development of the electron microscope. AAAS. Retrieved October 5, 2025, from https://www.aaas.org/taxonomy/term/10/development-electron-microscope

What is EDS/EDX? Introducing Energy Dispersive X-Ray Spectroscopy. (n.d.). Bruker. Retrieved October 5, 2025, from Energy-dispersive X-ray spectroscopy

What is Electron Microscopy? (2021, September 8). UMass Chan Medical School. Retrieved October 5, 2025, from https://www.umassmed.edu/cemf/whatisem/