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From tissue to cellular ultrastructure: closing the gap between micro- and nanostructural imaging
S S Biel1, K Kawaschinski, K-P Wittern
1Analytical Microscopy, Beiersdorf AG, Unnastrasse 48, D-20245 Hamburg, Germany. stefan.biel@beiersdorf.com
Journal of Microscopy
|October 1, 2003
Summary
This study introduces a novel freeze-substitution method for tissue analysis, enabling correlative light and electron microscopy on identical samples. This technique improves structural preservation and targeted ultrastructural investigation of specific cells.
Area of Science:
- Biomedical imaging
- Cell biology
- Histopathology
Background:
- Optimal structural preservation in tissue biopsies is crucial for both light and electron microscopy (EM).
- Current methods often use parallel, non-identically prepared samples, leading to potential discrepancies and fixation artifacts.
- High-pressure freezing offers superior preservation but is primarily used for EM, while light microscopy relies on chemical fixation with its inherent limitations.
Purpose of the Study:
- To develop a method for correlative light and electron microscopy on the same optimally preserved tissue sample.
- To overcome the limitations of separate preparation protocols for light and electron microscopy.
- To enable precise identification and targeted ultrastructural analysis of specific cells within complex tissues.
Main Methods:
- Modification of the freeze-substitution (FS) technique to incorporate fluorescent dyes during the initial exchange step.
- Investigation of resin-embedded, cryo-immobilized tissue using confocal laser scanning microscopy (CLSM) before EM examination.
- Targeted sectioning of identified cells or regions of interest for subsequent transmission electron microscopy (TEM).
Main Results:
- The modified FS technique allows for CLSM visualization of specific cellular structures within the entire tissue block.
- Fluorescent dye binding provides histological context for light microscopic analysis.
- Identified areas can be precisely targeted for ultrathin sectioning and detailed ultrastructural analysis by TEM, examining the exact same features.
Conclusions:
- This integrated approach significantly enhances the ability to perform correlative light and electron microscopy on identical, optimally preserved samples.
- It overcomes the challenges of sample preparation artifacts and the difficulty of locating specific features for EM analysis.
- The method facilitates a more accurate and comprehensive understanding of tissue structure from cellular to nanostructural levels.