Cryo-sem Preparation
Cryo-sem Preparation - Related Videos
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Cryo-electron Microscopy Specimen Preparation By Means Of a Focused Ion Beam
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Cited by 5 •
2014
Cryo Electron Microscopes, either Scanning (SEM) or Transmission (TEM), are widely used for characterization of biological samples or other materials with a high water content1. A SEM/Focused Ion Beam (FIB) is used to identify features of interest in samples and extract a thin, electron-transparent lamella for transfer to a cryo-TEM.
09:02
SEM Imaging of Biological Samples
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2023
Source: Peiman Shahbeigi-Roodposhti and Sina Shahbazmohamadi, Biomedical Engineering Department, University of Connecticut, Storrs, Connecticut A scanning electron microscope (SEM) is an instrument that uses an electron beam to nondestructively image and characterize conductive materials in a vacuum. As an analogy, an electron beam is to the SEM as light is to the optical microscope. The difference is that the electron microscope yields images of much higher resolution and magnification. The...
05:05
Preparation of High-Temperature Sample Grids for Cryo-EM
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Cited by 5 •
2021
This paper provides a detailed protocol for preparing sample grids at temperatures as high as 70 °C, prior to plunge freezing for cryo-EM experiments.
04:17
Chemical Drying: Biological Sample Preparation for Scanning Electron Microscopy (SEM)
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2023
Scanning electron microscopy (SEM) is a powerful tool to image—primarily—the surface features of a biological sample. Proper sample preparation, however, is critical to obtaining quality images. This video focuses on the dehydration and drying steps of preparing intact adult Drosophila for SEM.
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Scanning Electron Microscopy (SEM)
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2023
Source: Laboratory of Dr. Andrew J. Steckl — University of Cincinnati A scanning electron microscope, or SEM, is a powerful microscope that uses electrons to form an image. It allows for imaging of conductive samples at magnifications that cannot be achieved using traditional microscopes. Modern light microscopes can achieve a magnification of ~1,000X, while typical SEM can reach magnifications of more than 30,000X. Because the SEM doesn’t use light to create images, the resulting pictures it...
FAQs
Rapid freezing preserves more than temperature alone: it immobilizes water and cellular structures before they undergo the distortion, shrinkage, or chemical alteration associated with conventional preparation. In Cryo-SEM preparation, a cryogen such as liquid nitrogen slush therefore supports observation of biological material in a state closer to its original hydrated organization. This is especially important when structural relationships are the primary measurement.
Fracture and controlled sublimation determine which parts of a frozen specimen become available for observation. Fracturing exposes internal regions in addition to the external surface, while sublimation is controlled before conductive coating and imaging. Managing these stages helps present structural features without returning the specimen to the chemical dehydration and fixation pathway used in conventional preparation.
Vacuum transfer moves the rapidly frozen specimen into the SEM-compatible environment needed for subsequent fracture, controlled sublimation, and conductive coating. Its position in the workflow matters because the sample remains within a continuous frozen-state preparation rather than undergoing conventional dehydration before imaging. This preserves the method’s emphasis on near-native morphology and reduces opportunities for preparation-related structural alteration.
The main distinction is how the specimen’s water and structure are handled. Conventional dehydration and fixation can introduce shrinkage, distortion, and chemical alteration, whereas Cryo-SEM preparation immobilizes water by rapid freezing and examines the specimen after frozen-state processing. The resulting images can therefore provide a closer representation of biological organization, particularly for hydrated samples and interfaces.
A typical workflow begins by rapidly freezing the biological specimen, often with liquid nitrogen slush or another cryogen. The frozen sample is then transferred under vacuum, fractured to expose relevant regions, and subjected to controlled sublimation. Finally, it receives a conductive coating before scanning electron microscopy. Each stage prepares the specimen for structural imaging while maintaining the frozen-state approach.
Cryo-SEM preparation can be applied to cells, tissues, microorganisms, biomaterials, and hydrated interfaces. This range makes the approach useful when the interaction between a specimen and its surrounding hydrated environment is biologically important. It also supports comparisons across organizational levels, from cellular morphology to tissue structure and the surfaces where biological material contacts other materials.
The images can reveal surface and internal ultrastructure while preserving information about morphology, organization, and specimen-surface interactions. In biology, these outcomes help researchers assess how structures are arranged and how hydrated biological material relates to adjacent surfaces or biomaterials. The method is therefore valuable when structural context matters more than information obtained from chemically altered, dehydrated specimens.