Editing Histology (section)

==== Other materials ====

Paraffin wax does not always provide a sufficiently hard matrix for cutting very thin sections (which are especially important for electron microscopy).<ref name="Bancroft and Stevens, 1982" /> Paraffin wax may also be too soft in relation to the tissue, the heat of the melted wax may alter the tissue in undesirable ways, or the dehydrating or clearing chemicals may harm the tissue.<ref name="Bancroft and Stevens, 1982" /> Alternatives to paraffin wax include, [[epoxy]], [[Poly(methyl methacrylate)|acrylic]], [[agar]], [[gelatin]], [[Micro technique#Celloidin Method|celloidin]], and other types of waxes.<ref name="Bancroft and Stevens, 1982" /><ref name="Drury and Wallington, 1980" />

In electron microscopy epoxy resins are the most commonly employed embedding media,<ref name="Ross and Pawlina, 2016" /> but acrylic resins are also used, particularly where [[immunohistochemistry]] is required.

For tissues to be cut in a frozen state, tissues are placed in a water-based embedding medium. Pre-frozen tissues are placed into molds with the liquid embedding material, usually a water-based glycol, [[Optimal cutting temperature compound|OCT]], [[Tris-buffered saline|TBS]], Cryogen, or resin, which is then frozen to form hardened blocks.