Techniques for Life Scientists

TEM of resin embedded samples

This standard technique enables researchers to study biological structures at a nanometer resolution. Samples can be prepared by fixation with chemicals or low temperatures before being thinly sectioned and imaged with the transmission electron microscope. Serial thin sectioning can also be used to reveal 3D structural information.

Application examples: the 3D morphology of a cell’s organelles; the distribution of virus particles in infected cells; the types of synaptic connections within regions of the brain. see the protocol for tissue embedding

Pre and post-embedding immuno electron microscopy

These techniques allows specific molecules to be located within cells and tissues. Using gold labelled antibodies this method provides information about the location of molecules in relation to other cell structures with pinpoint accuracy.

For analysing: the position of receptors within synaptic connections; the location of proteins aggregates within cultured cells; the morphology of specific cell classes in the cerebral cortex

Negative staining of single particles

The main purpose is to surround or embed the biological object in a suitable electron dense material which provides high contrast and good preservation.

Application examples: The technique has mainly been used to examine particulate (purified) specimens such as: bacteriophages, proteins, DNA, liposomes etc..

Focussed ion beam milling and scanning electron microscopy

This method uses an ion beam to mill any material and an electron beam for imaging this milled surface. Combining the two allows for automated serially imaging of resin embedded tissues and cells. This approach can image many hundreds of cubic microns of tissue at nanometer resolution. 
Application examples Analysing the integration of cells to the surface of ceramic coated electrodes. Imaging in 3D the morphology of neurons and their connections within the cerebral cortex.

Scanning EM of biological samples

This protocol is used for imaging the surface of cells.