Scanning electron microscopy of human metaphase chromosomes

Area of Science:

• Cell Biology
• Microscopy Techniques
• Genetics

Background:

• Conventional scanning electron microscopy (SEM) sample preparation for chromosomes can alter surface morphology.
• Existing methods often prevent chromosome identification and banding, crucial for clinical cytogenetics.

Purpose of the Study:

• To develop a reliable SEM preparation method for chromosomes that preserves morphology and allows for identification and banding.
• To enable high-resolution imaging of chromosome surface topography and chromatin organization.

Main Methods:

• Standard cytogenetic preparation: methanol-acetic acid fixation and air-drying of metaphase spreads.
• Chromosome re-preparation for SEM: rehydration, glutaraldehyde fixation, and osmium impregnation using Thiocarbohydrazide (TCH).

Main Results:

• The developed method allows for high-resolution SEM imaging of chromosomes without metallic coating.
• Preserves chromosome topography, surface morphology, and chromatin organization.
• Visualizes structural alterations induced by G and C banding techniques.

Conclusions:

• This refined SEM preparation method is suitable for detailed ultrastructural analysis of banded chromosomes.
• It bridges the gap between light microscopy-based cytogenetics and high-resolution electron microscopy.