Long-range charge transport in single G-quadruplex DNA molecules.

Area of Science:

• Molecular electronics
• Biophysics
• Materials science

Background:

• DNA and DNA-based polymers offer programmable structures for molecular electronics.
• Previous charge transport studies in DNA yielded inconsistent results, hindering device development.
• Efficient current transport through individual DNA molecules remains a significant challenge.

Purpose of the Study:

• To investigate reproducible charge transport in guanine-quadruplex (G4) DNA molecules.
• To explore the feasibility of using G4 DNA in molecular electronic devices.
• To understand the mechanism of charge transport in DNA over nanometre distances.

Main Methods:

• Adsorption of G4 DNA molecules onto a mica substrate.
• Measurement of electrical currents across G4 DNA molecules at varying distances.
• Theoretical modeling to elucidate charge transport mechanisms.

Main Results:

• Reproducible charge transport was observed in G4 DNA molecules on mica.
• Measured currents ranged from tens to over 100 picoamperes.
• Transport occurred over distances from tens to over 100 nanometres.
• Evidence suggests thermally activated, long-range hopping between multi-tetrad segments.

Conclusions:

• G4 DNA exhibits promising charge transport properties for electronic applications.
• The findings support the use of G4 DNA in developing molecular wires and programmable circuits.
• This research could stimulate further interest in DNA-based electronic components.