Polyester or epoxy: assessing embedding product efficacy in paleohistological methods

Area of Science:

• Paleontology
• Vertebrate Physiology
• Materials Science

Background:

• Histological examination of bone microstructure aids in understanding vertebrate physiology.
• Traditional methods involve embedding specimens in polyester or epoxy resins for thin sectioning.
• Epoxy resin is often preferred for thin sections (<100 µm) of small or modern bone, but is more expensive.

Purpose of the Study:

• To test the assertion that polyester resin is unsuitable for thin sections <100 µm.
• To compare the suitability of polyester versus epoxy resin for embedding and sectioning modern and fossil hard tissues.
• To evaluate material loss and tissue visibility in thin sections prepared with different resins.

Main Methods:

• Modern and fossil bones, teeth, and scales were embedded in either polyester or epoxy resin.
• Specimens were sectioned and polished to varying thicknesses using standard protocols.
• Thin sections were ground until material integrity was lost to compare resin performance.

Main Results:

• Thin sections from both polyester and epoxy resins allowed for clear visualization of tissue microstructure.
• No significant difference in slide thickness at which material loss occurred was observed between the two resin types.
• Final slide thickness was more dependent on hard tissue composition than resin type.

Conclusions:

• Polyester resin is a suitable alternative to epoxy resin for preparing thin sections of undecalcified modern and fossil hard tissues.
• Polyester resin does not compromise tissue visibility or material integrity in the short term.
• This finding may reduce costs associated with paleontological and histological research.