Tools

Transmitted Light  Microscopy

- Optical magnification of transparent, thin objects
- Maximum resolution: 200 nm
- Usual magnifications: 40-1000x

  • Click here to view our slide show "Transmitted Light Microscopy"


  • Options:
    - Brightfield : light is transmitted through the object. Contrast is caused by the absorbance of light in dense areas.
    - Darkfield : observation of scattered light . Structures of transparent objects with low contrast can be displayed

    - Two optical paths allow a three-dimensional impression of the examined object
    - Normally the object is illuminated from above (reflected light microscopy). This enables the observation og thick, compact objects
    - Maximum resolution: 5µm - max. 0.5µm. For comparison: the max. resolution for the human eye lies around 330 µm.
    - Usual magnifications: 6-150fold

  • Click here to view our slide-show "Stereo microscopy"


  • The stereo microscope is best suited for screening prior to higher magnifications in futher microscopes, like the scanning electron microscope.

    Scanning Electron Microscopy

    - In electron microscopes (EM) the images are formed by the interaction of electrons with the object.
    - In scanning electron microscopes (SEM) the sample is scanned with a focused beam of electrons.
    - Surface images with a high depth of field are characteristic.
    - Usual resolutions: 1-30nm (depending on the instrument). Current limitation ca. 0.4 nm.
    - Usual magnifications: 10 - 300.000x

  • Click here to view our slide show "Scanning electron microscopy"


  • Usual options:
    - Detection of backscattered or secondary electrons.
    - Elemental analysis by EDX (energy dispersive X-ray spectroscopy)

    Transmission Electron Microscopy

    - In electron microscopes (EM) the images are formed by the interaction of electrons with the object.
    - In transmission electron microscopes (TEM) electrons are transmitted through an ultra-thin specimen (usually 10 - 100nm thick).
    - No surface representations, but images of the whole inner structure of the specimen.
    - Usual magnifications: 1.000-1.000.000x

    Resolution limits in life science area depend on the methodological approach.
    Examples:
    - Cryo-electron tomography: ~4 nm
    - Negative staining of macromolecules: ~ 1.5 nm
    - 3D cryo-electron microscopy of macromolecules: ~ 3 Å
    - Electron crystallography of macromolecules: ~ 1 Å

    Update in progress ...

    Surface Analysis

    Update in progress ...

    Update in progress ...

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