Dynamics of DNA-Templated Ultrafine Silver Nanowires Formation

TL;DR

This study investigates the formation kinetics of DNA-templated silver nanowires at the single-molecule level, revealing how chemical reduction influences their structure and providing insights through experimental and simulation approaches.

Contribution

It presents the first detailed kinetic analysis of DNA-templated silver nanowire formation combining force spectroscopy and simulations.

Findings

Ag+ ions compact DNA structure, increasing force by 5.5-7.5 pN within 2 minutes.

Hydroquinone decreases force by 4-5 pN, indicating structural changes.

Morphological analysis confirms dense silver bridging DNA strands.

Abstract

Recent research on silver nanowires prepared on DNA templates has focused on two fundamental applications: nano-scale circuits and sensors. Despite its broad potential, the formation kinetics of DNA-templated silver nanowires remains unclear. Here, we present an experimental demonstration of the formation of silver nanowires with a diameter of 2.2+0.4 nm at the single-molecule level through chemical reduction. We conducted equilibrium and perturbation kinetic experiments to measure force spectroscopy during the formation of Ag+ -DNA complexes and Ag-DNA complexes, using optical tweezers combined with microfluidics. The addition of AgNO3 resulted in an increase in force of 5.5-7.5 pN within 2 minutes, indicating that Ag+ compacts the DNA structure. In contrast, the addition of hydroquinone caused the force to decrease by 4-5 pN. Morphological characterization confirmed the presence of a dense structure formed by silver atoms bridging the DNA strands, and revealed conformational differences before and after metallization. We compare our experimental data with Brownian dynamics simulations using a coarse-grained double-stranded DNA (dsDNA) model that provides insights on the dependency of the force on the persistence length.