Bioelectromechanical imaging by scanning probe microscopy: Galvani's experiment at the nanoscale

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Electrical and mechanical phenomena are coupled in biological systems.
• This coupling is a fundamental property observed since the 18th century.

Purpose of the Study:

• To measure the sub-Angstrom mechanical response of biological systems using electric bias.
• To demonstrate the visualization of molecular structures at high spatial resolution.

Main Methods:

• Employing scanning probe microscopy (SPM) with a conductive tip.
• Applying an electric bias to the SPM tip to induce mechanical response.
• Achieving 5 nm spatial resolution for imaging.

Main Results:

• Successfully visualized the spiral shape and orientation of protein fibrils in human teeth.
• Determined the molecular bundle orientation of chitin in butterfly wings.
• Demonstrated sub-Angstrom mechanical response measurement.

Conclusions:

• SPM techniques are applicable for determining molecular orientation in biological samples.
• This method offers high-resolution insights into the electromechanical properties of biomaterials.