Base Pair Stacking Modulates Solid-State Charge Transport in DNA Hairpins.

Area of Science:

• Molecular Biophysics
• Nanotechnology
• Materials Science

Background:

• Solid-state charge transport (CT) in DNA is of great interest.
• Predicting and controlling DNA CT is difficult due to unclear relationships with base pair stacking.
• Ill-defined systems lead to ambiguous conclusions in DNA CT research.

Purpose of the Study:

• To establish a well-defined system for studying DNA charge transport.
• To investigate the correlation between DNA conformation and charge transport.
• To understand the mechanism of charge transport enhancement in DNA.

Main Methods:

• Construction of well-defined self-assembled monolayers using DNA hairpins.
• Measurement of solid-state current-voltage characteristics.
• Circular dichroism spectroscopy in solution to analyze DNA conformation.

Main Results:

• Nearly positive-linear correlations were observed between DNA conformation and charge transport in DNA hairpins.
• Metal ion chelation, specifically with Hg ions, enhanced charge transport.
• Enhanced CT was attributed to improved DNA-electrode energy coupling, not changes in the energy barrier.

Conclusions:

• DNA hairpins provide a well-defined model for studying DNA charge transport.
• DNA conformation significantly influences charge transport.
• Metal ion-induced modulation of DNA conformation impacts charge transport primarily through altered electrode coupling.