Conclusion
Although STEM is mainly used in materials sciences, there are many applications in biology that would benefit from STEM imaging. However, until now very few groups have explored the potential of STEM imaging. The aim of this review was to describe the STEM methods used in parasitology and other fields. We have demonstrated using several examples that STEM and cryo-STEM are superior to TEM and cryo-TEM under specific conditions. STEM methods perform remarkably well with thick samples. Since parasites are thick samples, STEM imaging can be particularly beneficial. Cryo-STET in particular, is a perfect fit for the study of micrometre thick samples as they can simply be deposited or grown directly on electron microscopy grids, which makes sample preparation protocol easier and faster to execute.
Another important detail of STEM imaging is its relative low cost compared to the acquisition of a TEM-related equipment (direct electron detector, energy filter). Electron microscopes used in biology are more and more often equipped with STEM detectors. Because STEM is now being used for more than a decade, there are many tools available, from data collection to image analysis. The transition from room temperature to cryo-conditions will be motivated by the possibility to i) recover native structural information and ii) perform CLEM experiments. These events are a huge benefit for the scientists who would like to ride on the STEM wave and want to join cutting-edge technologies.