Dynamics of ultrafine silver implanted DNA nanowire formation

Abstract

Recent research on silver nanowires prepared on DNA templates has focused on two fundamental applications: nano-scale circuits and sensors. Despite their broad potential, the formation kinetics of silver implanted DNA 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 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 into the dependency of the force on the persistence length.