Transmission Electron Microscopy

Temop

Local application

Transmission electron microscopy in biological science is a high resolution technique used in the study of cells/ultrastructure, macromolecules, bacteria and virus particles.

The operating environment of a TEM dictates the use of specialist preparation techniques.  Sectioning the sample allows us to look at cross-sections through samples to view internal (ultra)structure.  Biological material is chemically fixed, dehydrated through an acetone or ethanol series and then embedded in a plastic resin.  The sample is then thin sectioned by a process known as ultramicrotomy, sections of 80 - 100 nm thickness are collected on metal mesh 'grids' and contrasted with electron dense stains before observation in the TEM.  Many modifications to the basic protocol can be applied to achieve many different goals, immunogold labelling for example; the in situ localisation of specific tissue constituents using antibody and colloidal gold marker systems.  Cryo-ultramicrotomy is the ultrathin sectioning of fixed, cryo-protected, frozen hydrated samples at very low temperatures, a technique used when less harsh tissue processing is required - particularly useful in immunogold investigations.

Metal shadowing and negative staining are two techniques used to investigate the shape and size of isolated macromolecules, bacteria and virus.

The samples shown above are (clockwise from top left) negatively stained bacteriophage, sectioned bacteria, striated muscle, Golgi apparatus, individual cells and finally, de-membranated axonemes - in both transverse and longitudinal view.

 

Major equipment available


JEOL 1400 Transmission Electron Microscope with EMSIS Xarosa 20MP CMOS digital camera

Leica and RMC ultramicrotomes

Quorum Q150T ES coating unit - carbon coating, aperture cleaning and glow discharge attachments

 

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