Cryo-sem
Cryo-sem - Related Videos
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...
11:41
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...
05:05
Preparation of High-Temperature Sample Grids for Cryo-EM
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Cited by 4 •
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.
09:53
Micropatterning Transmission Electron Microscopy Grids to Direct Cell Positioning within Whole-Cell Cryo-Electron Tomography Workflows
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Cited by 29 •
2021
The goal of this protocol is to direct cell adhesion and growth to targeted areas of grids for cryo-electron microscopy. This is achieved by applying an anti-fouling layer that is ablated in user-specified patterns followed by deposition of extra-cellular matrix proteins in the patterned areas prior to cell seeding.
10:54
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.
FAQs
Rapid freezing locks hydrated or volatile material into a near-native frozen state, limiting the structural collapse or evaporation that can occur during conventional preparation. Under cryogenic vacuum conditions, the specimen remains available for surface imaging with an electron beam. This preservation helps distinguish genuine pore, interface, biofilm, or particle architecture from changes introduced by drying or handling.
Fracturing physically exposes internal features that would remain hidden on an intact surface. A brief freeze-drying step may also be used before electron-beam imaging when additional exposure is needed. These preparation choices allow investigators to examine structures within soil, mineral-organic materials, biofilms, or other water-rich specimens while retaining information that ordinary surface viewing might not reveal.
Specimen hydration, volatility, freezing speed, and preservation under cryogenic vacuum conditions all influence the resulting observation. Rapid freezing is important because the method is intended to maintain a near-native state, while unsuitable handling can allow evaporation or structural collapse. Fracturing or brief freeze-drying must also be selected according to whether surface or internal features are the primary target.
A basic workflow starts by rapidly freezing the hydrated or volatile specimen. The frozen sample is then transferred into the scanning electron microscope under cryogenic vacuum conditions. If internal structures need examination, researchers may fracture the specimen or briefly freeze-dry it before electron-beam imaging. The resulting preparation supports observation of preserved surfaces and exposed internal features.
Researchers choose Cryo-SEM when evaporation or collapse during conventional preparation could obscure important structure. Environmental examples include water-rich soils, biofilms, microbial communities, aerosols, and materials containing mineral-organic interfaces. Preserving these specimens helps investigations of pollutant transport, microbial habitats, particle structure, and environmental transformations where preparation-related alteration could affect interpretation.
The images can show soil pores, mineral-organic interfaces, biofilms, microbial communities, aerosols, and other structures within water-rich materials. These observations provide visual evidence relevant to pollutant transport, microbial habitat organization, particle structure, and environmental transformations. Their value lies in connecting preserved physical features with processes occurring in environmental specimens rather than viewing preparation-induced artifacts alone.