Probing peptide nanowire conductivity by THz nanoscopy

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Microbial nanowires are explored for renewable energy and bioelectronics due to their conductivity.
• Existing conductivity measurement methods for nanowires lack reliability, leading to data variability.
• A precise nano-scale conductivity measurement technique is needed for bio-materials.

Purpose of the Study:

• To develop and validate a non-destructive nano-scale conductivity measurement technique for synthetic peptide nanowires.
• To investigate the influence of peptide aromaticity on electrical conductivity.
• To establish a reliable method for quantifying conductivity in bio-inspired materials.

Main Methods:

• Utilized a terahertz scanning near-field microscope (s-SNOM) for non-destructive conductivity measurements.
• Developed a novel peptide conductivity measurement technique based on a triple standards calibration method.
• Compared the conductivity of a synthetic peptide with aromatic residues (W6) against a control peptide (L6).

Main Results:

• The study reports the first quantitative nano-scale terahertz s-SNOM investigation of peptide conductivity.
• The peptide incorporating aromatic residues (W6) demonstrated approximately six times higher electrical conductivity compared to the control (L6).
• The terahertz-based method proved effective for simple sample preparation and avoided pitfalls of contact-based techniques.

Conclusions:

• Terahertz radiation-based non-destructive approaches are suitable for investigating peptide conductivity.
• Designer peptides serve as effective model systems for understanding electron transfer in biopolymers.
• This technique could advance the development of bioelectronic materials and sensors by providing reliable conductivity data.