What are the steps involved in TEM sample preparation?
Preparing samples for TEM is a meticulous process that involves several steps to ensure the preservation and contrast of the specimen:
Fixation: The sample is fixed using chemicals like glutaraldehyde and osmium tetroxide to preserve cellular structures. Dehydration: The fixed sample is dehydrated through a series of alcohol or acetone baths to remove water. Embedding: The dehydrated sample is embedded in a resin, such as epoxy or acrylic, to provide support for ultra-thin sectioning. Sectioning: Ultra-thin sections (50-100 nm) are cut using an ultramicrotome and placed on copper grids. Staining: The sections are stained with heavy metals like lead citrate and uranyl acetate to enhance contrast.
