In transmission electron microscopy (TEM), contrast is artificially enhanced by staining specimens with electron-dense materials containing heavy metal atoms, such as uranyl acetate or osmium tetroxide, rather than colored dyes. Prior to this staining process, the extremely thin sample sections are typically secured to fine copper wire or carbon-fiber grids to support them during observation.

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The transmission electron microscope (TEM) is a type of electron microscope that functions analogously to a brightfield microscope. It utilizes an electron gun to release an electron beam that is directed from above the specimen and focused using a magnetic lens. The electrons pass through the specimen and are then projected onto a detector to capture the image. TEM is particularly useful for observing small, thin specimens, such as tissue sections and subcellular structures.

Transmission Electron Microscope (TEM)

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Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

A magnetic lens consists of electromagnets and is utilized in electron microscopes, such as the transmission electron microscope (TEM), to focus the electron beam onto the specimen. This magnetic mechanism replaces the traditional glass lenses used to focus light in optical microscopes.

Magnetic Lens

For a transmission electron microscope (TEM) to function properly, the specimen and the electron beam must be placed in a vacuum. Additionally, the specimen must be fully dehydrated and cut extremely thin, typically between $${}20-100$$ nm thick, to allow the electrons to successfully pass through it.

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