Advantages of embedment‐free section transmission electron microscopy

The usefulness of embedment‐free section transmission electron microscopy (TEM) is stressed for present and future morphological analyses, and several examples are demonstrated which are revealed in sections for the first time by this method: en‐face views of slit diaphragm of renal glomerulus and fenestrated diaphragm of capillary endothelium, transparency of neural myelin, attenuated endothelium and some basement laminae, labyrinth architecture of vacuoles within lipid droplets, and enhanced 3D effect of ultrastructures, the latter of which is the case in electron tomography. In addition, the biological significance of structured appearance (microtrabecular lattices) of the cytoplasmic matrix, which is disclosed by this method, are briefly reviewed in relation to the sol–gel transition of cytoplasmic heterogenous proteins. Since the ultrastructures of various cells and tissues in this method are confirmed to be well correspondent to those in conventional epoxy section TEM except for isotropic dimensional changes, and because there is no necessity for any special expensive equipments other than those for the conventional TEM, the embedment‐free section TEM method with these advantages, deserves much more wide application to the morphological research including electron tomography. Microsc. Res. Tech. 76:1257–1265, 2013. © 2013 Wiley Periodicals, Inc.