Low temperature backscattered electron imaging in the study of human tissues

Area of Science:

• Electron Microscopy
• Biomedical Imaging
• Pathology

Background:

• Conventional microscopy often requires tissue fixation and dehydration, which can alter cellular structures.
• Examining fresh, hydrated tissue is crucial for preserving native morphology and enabling subsequent analyses.

Purpose of the Study:

• To describe a novel scanning electron microscopy (SEM) technique for the examination of bulk, fresh, hydrated human tissue.
• To evaluate the utility of this technique in visualizing cellular and stromal components within human breast carcinoma samples.

Main Methods:

• Fresh human tissue samples were cryo-frozen and planed in a cryoultramicrotome.
• Samples were examined in a low-temperature scanning electron microscope using secondary and backscattered electron modes after water sublimation.
• Adjacent tissue sections were prepared for light and transmission electron microscopy.

Main Results:

• The backscattered electron mode allowed clear distinction between neoplastic cells and surrounding adipose/fibrous tissue in breast carcinoma.
• Collagenous stroma, carcinoma cells, and perivascular/perineural infiltrates were identifiable within the tumor microenvironment.
• The technique preserved tissue integrity, allowing for subsequent light and transmission electron microscopy.

Conclusions:

• This low-temperature SEM method enables detailed imaging of unfixed, hydrated human tissues.
• Backscattered electron imaging is valuable for differentiating tissue components in complex samples like carcinomas.
• The technique holds potential for analyzing small tissue samples intended for biochemical, histochemical, or immunologic investigations, avoiding fixation artifacts.