ANALYSIS OF HUMAN FIBRINOGEN BY SCANNING TRANSMISSION ELECTRON MICROSCOPY

The scanning transmission electron microscope (STEM) offers several advantages in studying a molecule such as fibrinogen. Molecules and their domains observed unstained in dark field can be identified directly by their mass. Thus, it is possible to correlate the STEM image directly with biochemical models. Lack of phase contrast when using the large angle annular detector makes image intensity directly interpretable in terms of mass thickness (no oscillations in the contrast transfer function). Certain specimen preparation artifacts such as denatured protein films are detected easily in the STEM and can be avoided through suitable specimen preparation techniques. 50 references.