Reversible Regulation of Long-Distance Charge Transport in DNA Nanowires by Dynamically Controlling Steric Conformation

Understandingof DNA-mediated charge transport (CT) issignificantfor exploring circuits at the molecular scale. However, the fabricationof robust DNA wires remains challenging due to the persistence lengthand natural flexibility of DNA molecules. Moreover, CT regulationin DNA wires often relies on predesigned sequences, which limit theirapplication and scalability. Here, we addressed these issues by preparingself-assembled DNA nanowires with lengths of 30-120 nm usingstructural DNA nanotechnology. We employed these nanowires to plugindividual gold nanoparticles into a circuit and measured the transportcurrent in nanowires with an optical imaging technique. Contrary tothe reported cases with shallow or no length dependence, a fair currentattenuation was observed with increasing nanowire length, which experimentallyconfirmed the prediction of the incoherent hopping model. We alsoreported a mechanism for the reversible CT regulation in DNA nanowires,which involves dynamic transitions in the steric conformation.

Automated summary

We prepared self-assembled DNA nanowires with lengths of 30-120 nm using structural DNA nanotechnology and measured the transport current in these nanowires by plugging individual gold nanoparticles into a circuit. Contrary to previous reports, we observed a significant current attenuation with increasing nanowire length, confirming the prediction of the incoherent hopping model. We also proposed a mechanism for the reversible regulation of charge transport in DNA nanowires involving dynamic transitions in steric conformation.