title: Scanning electron microscopy.
abstract: Scanning electron microscopy (SEM) remains distinct in its ability to allow topographical visualization of structures. Key elements to consider for successful examination of biological specimens include appropriate preparative and imaging techniques. Chemical processing induces structural artifacts during specimen preparation, and several factors need to be considered when selecting fixation protocols to reduce these effects while retaining structures of interest. Particular care for proper dehydration of specimens is essential to minimize shrinkage and is necessary for placement under the high-vacuum environment required for routine operation of standard SEMs. Choice of substrate for mounting and coating specimens can reduce artifacts known as charging, and a basic understanding of microscope settings can optimize parameters to achieve desired results. This unit describes fundamental techniques and tips for routine specimen preparation for a variety of biological specimens, preservation of labile or fragile structures, immune-labeling strategies, and microscope imaging parameters for optimal examination by SEM.
authors.affiliation: Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Fischer
authors.forename: Bryan T
authors.initials: BT
authors.lastname: Hansen
authors.forename: Vinod
authors.initials: V
authors.lastname: Nair
authors.forename: Forrest H
authors.initials: FH
authors.lastname: Hoyt
authors.forename: David W
authors.initials: DW
authors.lastname: Dorward
mesh_terms: D035843:Biomedical Research / Q000295:instrumentation / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000295:instrumentation* / Q000379:methods*; D013048:Specimen Handling / Q000379:methods*