Scanning tunneling microscopy of an ionic crystal: ferritin core

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Ferritin is a protein that stores iron, crucial for biological systems.
• Understanding ferritin's structure is key to various biological and medical applications.
• High-resolution imaging techniques are essential for nanoscale structural analysis.

Purpose of the Study:

• To investigate the direct imaging of ferritin molecules using scanning tunneling microscopy (STM).
• To determine the structural and dimensional characteristics of ferritin in air.
• To assess the capability of STM for imaging thin ionic crystals at high resolution.

Main Methods:

• Direct imaging of ferritin molecules in ambient air using scanning tunneling microscopy (STM).
• Comparison of lateral dimensions with electron microscopy data.
• Analysis of the vertical dimension and structural arrangement of ferritin cores.

Main Results:

• STM provided high-resolution images of ferritin molecules in air.
• Lateral dimensions obtained via STM were consistent with electron microscopy.
• Partially naked ferritin cores exhibited a hexagonal structure with a lattice constant of 4.9 ± 0.5 Å.

Conclusions:

• Scanning tunneling microscopy is a viable technique for imaging ferritin molecules directly in air.
• STM can resolve nanoscale structural details, including hexagonal lattices in ferritin cores.
• The study validates STM's utility for high-resolution imaging of thin ionic crystals.