Conventional and high resolution scanning electron microscopy of biological sectioned material.
Intracellular structures of embedded biological tissues (rat kidney, myocardium and small intestine) were observed by conventional-scanning electron microscopy (C-SEM) and high-resolution scanning electron microscopy (HR-SEM) after glass knife sectioning. C-SEM of semi-thin sections of material processed the same way as conventional transmission electron microscopy (TEM) provided strong backscattered electron (BSE)-dependent, two-dimensional secondary electron images (SEI(-)) which precisely integrated and further extended previous light microscopy (LM) observation of the same specimen. In addition, the three-dimensional (3-D) arrangement of intracellular organelles was appreciated using a mixture of acetone-soluble acrylic resin in place of epoxy resin embedding. Since the identification of such structures was hampered by the use of conventional fixations we introduced osmium maceration as a preliminary step to remove excess cytoplasmic matrix from the specimen. Consequently, semi-thin sections for LM and thin sections for TEM were obtained by sectioning of the tissue blocks. After resin removal, the sections were successfully observed in 3-D under a C-SEM. Finally, the deembedded, osmium treated sections proved to be smooth enough to facilitate deposition of continuous, ultra-thin (1 nm) chromium films and, therefore, HR-SEM studies of macromolecular cell membrane structures.
Scala
C
C
Institute of Clinical Electron Microscopy, S. Orsola Hospital, University of Bologna, Italy.
Cenacchi
G
G
Preda
P
P
Vici
M
M
Apkarian
R P
RP
Pasquinelli
G
G
D000818:Animals; D007421:Intestine, Small / Q000648:ultrastructure*; D007668:Kidney / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008867:Microtomy / Q000379:methods; D009206:Myocardium / Q000648:ultrastructure*; D051381:Rats