Electrical Characterization of DNA Origami Structures with PEG-PLL coating for improved robustness

TL;DR

This study investigates the electrical properties of DNA origami structures with PEG-PLL coating, demonstrating enhanced robustness and measurable impedance, and highlighting the importance of coating for conductivity and electrode stability.

Contribution

It provides the first detailed electrical characterization of PEG-PLL coated DNA origami, showing improved robustness and measurable impedance compared to uncoated structures.

Findings

PEG-PLL coating increases DNA origami robustness.

Coated structures show ohmic resistance up to 3.4 MΩ.

Uncoated structures are nonconductive.

Abstract

Electrical conductivity of DNA has been a controversial topic since it was first proposed in 1962. Disparities in the experimental results can often be explained by differences of the ambient or experimental conditions. We report the dielectrophoretic trapping and electrical characterization of two rod-like DNA origami structures with different modifications. These were 12helix bundles, with either thiol-ends or polyA single-stranded overhangs, and 30-helix bundles, with thiol-ends and either with or without a PEG-PLL coating. The observed impedance spectra showed ohmic resistances ranging from 500 k$\Omega$ to 3.4 M$\Omega$ for the 30-helix bundle structures with a PEG-PLL coating. DNA origami structures without the coating were always nonconductive. Depending on the structure, destruction of the gold nanoelectrodes occurred frequently during the trapping of DNA origami nanostructures. This indicates high currents, resulting from the trapped conductive nanostructures.