STEM detector in SEM and TEM comparison
Today, transmission electron microscopes (TEMs) are the go-to instruments for imaging ultra-thin sections of soft tissues for cell biology and pathology. Using TEMs, scientists have been able to view cell interiors and organelle structures in precise detail—contributing to many significant advances in biomedical research.
Near TEM-quality images using a SEM
While STEM systems have been available on TEM instruments for some time, they have not been commonly used for ultrastructural examination in cell biology and pathology. Yet now, scientists can achieve near-TEM quality images when studying thin, soft tissue samples using a scanning electron microscope (SEM). Pairing a scanning transmission electron microscopy (STEM) detector in a SEM, users can obtain high-resolution images of soft tissues at low energy levels to get the contrast they need while preserving the structure of their samples. Moreover, they can quickly acquire these images, advancing their biology research using an easy-to-use desktop SEM that requires little training.
Imaging human brain tumor tissue using a SEM and a STEM detector, one can see valuable ultrastructural features including myelin sheathed axons, mitochondria including the cristae layout, and astrocyte-like cells containing prominent cytoplasmic filament bundles and vesicles. The relations to other organelles and cellular structures can also be observed.
Ultrastructural analysis of soft tissues
To demonstrate the high-resolution image quality that can obtained using a SEM with a STEM detector, we recently prepared samples of a kidney, brain, and pancreas—imaging them with the highly automated Thermo Scientific Phenom Pharos G2 Desktop FEG-SEM and a STEM detector.
All three soft tissue samples were conventionally prepared for TEM imaging and then imaged using just 15 kV to minimize sample damage. And in all three cases the images showed the detailed structure in high resolution and adequate contrast—making it easy to analyze features of interest, while detecting small cellular changes.
By pairing a SEM with a STEM detector, scientists can extend soft tissue imaging to more users—increasing productivity while obtaining TEM-like images that advance their biomedical research.
To learn more about using low-kV STEM technology, please check out our application note, “TEM-like imaging on the Phenom Pharos G2 Desktop FEG-STEM.”
Rogier Miltenburg is an applications and product specialist at Thermo Fisher Scientific
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