The Microscopy Unit has a broad range of both preparative techniques and transmission electron microscopes, each with unique capabilities, to meet the diverse needs of NIAID research scientists.
Applications for negative staining include imaging whole mounts of viral suspensions, bacteria, macromolecules, isolated membrane, and cellular components. Small aliquots of the suspensions typically are applied to coated grids and excess fluid wicked away with filter paper. An electron dense stain is likewise applied and excess is wicked away, resulting in a thin layer of stain enabling better visualization of electron lucent structures.
Specimens that are too thick for visualization by negative staining can be chemically fixed, embedded in resin, and then cut into thin slices using an ultramicrotome. These slices, or “sections,” can be picked up on grids for viewing in an electron microscope.
Last Updated August 16, 2013