Specimens for electron microscopy are embedded in glycol methacrylate.

• A. True
• B. False
• C. Not sure
• D. Cannot be determined

Answer: (B)

For electron microscopy, the embedding medium must form a very hard, stable matrix that can withstand ultrathin sectioning and preserve fine ultrastructure. Epoxy resins such as Epon or Araldite are typically used because they polymerize into rigid blocks that cut cleanly at 50–100 nm and withstand heavy metal staining for EM contrast. Glycol methacrylate is a resin designed mainly for light microscopy; it yields a softer block and is favored when immunohistochemistry or antigen preservation is a priority, but it does not provide the hardness and stability needed for ultrathin EM sections. Thus, specimens for electron microscopy are not embedded in glycol methacrylate.