Cryogenic Electron Microscopy (Cryo-EM): A Cutting-Edge Technology for Nanoscale Analysis
A nanoscale analysis method for biomolecules and advanced materials
Cryo -electron microscopy (Cryo-EM or Cryo-EM) is a high-resolution microscopy technique that analyzes biological samples and complex materials at the nanoscale. By preserving structures in their native state through ultrafast cooling, this method eliminates the preparation artifacts often encountered in conventional electron microscopy. Used in biomedical research, biotechnology, the pharmaceutical industry, and nanotechnology, Cryo-EM is essential for the study of proteins, viruses, nanoparticles, and polymers.
What are the different types of cryo-electron microscopy?
Cryo-TEM (transmission electron microscopy) and cryo-SEM (scanning electron microscopy) are two advanced imaging techniques used for the analysis of samples in their native state, through rapid vitrification that preserves their original structure.
- Cryo-TEM allows the observation of internal structures at very high resolution by transmitting an electron beam through ultra-thin sections of frozen samples. It is particularly suitable for the study of cells, tissues, proteins, biomolecular complexes or nanoparticles, and can be coupled with methods such as immunolabeling or 3D tomography.
- Cryo-SEM, on the other hand, is dedicated to surface analysis. It offers precise visualization of topography, interfaces, and interactions while avoiding any deformation related to desiccation. Used particularly for biological and organic materials, it allows the morphological evolution of hydrated samples to be observed without the use of chemical fixatives. These techniques can also be combined with elemental microanalysis (EDS) for detailed chemical characterization.
How does cryogenic electron microscopy work?
Cryogenic electron microscopy relies on a combination of rapid cooling and transmission electron imaging. Its operation is based on several steps:
- Sample vitrification : The sample is rapidly frozen in liquid ethane or liquid nitrogen. This process prevents the formation of ice crystals and maintains the structural integrity of the material.
- Electron beam or electron transmission observation : for both techniques (MET and SEM), electrons are sent through the frozen sample, generating very high-resolution images.
- Image acquisition and reconstruction : Advanced image processing software allows 3D reconstructions to be obtained and nanometric structures to be analyzed in detail.
Technical characteristics of cryogenic electron microscopy
- High-resolution imaging : Near-angstrom resolution, ideal for analyzing proteins and biological complexes.
- Cryogenic cooling : Optimal preservation of molecular structures and nanomaterials in their native state.
- Sample preservation : No chemical fixation or dyes that could alter the sample.
- 3D reconstruction : Ability to model complex biological structures from images obtained from different angles.
For which matrices is cryogenic electron microscopy suitable?
This method is particularly effective for the study of the following matrices:
Industrial applications of cryogenic electron microscopy
Cryogenic electron microscopy is an essential technology for many industrial sectors:
Léa Géréec
Technical and scientific advisor
