Transmission Electron Microscopy (TEM) utilises a high energised electron beam to penetrate through an ultrathin specimen which is mostly less than 100 nm. Electron signals are collected from the interaction between the incident beam and the sample. However, compared to SEM, it collects the transmitted electrons to form an image. Due to this nature, the image resolution is generally higher than SEM imaging.
TEM is useful for analysis of a range of samples, including (but not limited to) fly brains, micro-plankton, nerve cells etc. If you're interested in seeing how PEMC have used the TEM in research, take a look at our research case study on
the formation and secretion of heterococcoliths by Coccolithus Pelagicus.
At PEMC, we are able to prepare these ultrathin samples suitable for Transmission Electron Microscopy in house using our suite of biological sample preparation equipment. To prepare these samples, they are first fixed, before being dehydrated to remove any water from within the samples. These are then placed in resin which is polymerised by baking overnight to produce hard resin blocks.
The samples are then cut down and sliced into thin sections using our microtomes (Leica EM UC 7 Ultramicrotome or Reichert-Jung Ultracut E) until an area of interest is found, before being placed on a copper grid and ready for analysis.