Micro-CT scouting for transmission electron microscopy of human tissue specimens

Area of Science:

• Materials Science
• Biomedical Engineering
• Pathology

Background:

• Transmission electron microscopy (TEM) offers sub-nanometre resolution for volumetric samples.
• Metal staining enhances contrast in pathology specimens but renders them opaque to light microscopy.
• Locating specific regions of interest within stained samples for TEM is a time-consuming process involving extensive sectioning.

Purpose of the Study:

• To introduce and evaluate micro-computed tomography (micro-CT) scouting as a method for noninvasively identifying regions of interest in samples for TEM.
• To streamline the process of preparing tissue samples for high-resolution ultrastructural analysis using TEM.

Main Methods:

• Utilized a bench-top micro-CT scanner with 10 micrometre resolution for sample scouting.
• Applied micro-CT to identify mucous membrane patches in osmium-stained human nasal scraping samples.
• Guided ultra-thin sectioning for TEM based on micro-CT identified regions of interest.

Main Results:

• Successfully located regions of interest within osmium-stained human nasal tissue using micro-CT.
• Reduced the number of sections required for analysis from approximately 20 (light microscopy) to three.
• Enabled direct TEM inspection of cilia in membrane epithelial cells with nanometre resolution.

Conclusions:

• Micro-CT scouting is an effective noninvasive technique for guiding sample sectioning for TEM.
• This approach significantly decreases the time and labor associated with preparing pathology samples for high-resolution microscopy.
• The method facilitates efficient identification and analysis of ultrastructural details in biological tissues.