Dynamic Control of DNA Origami Nanostructures via Gold Nanoparticles

Abstract

A major direction of research in DNA origami nanotechnology is the folding of DNA into complex 3D shapes with the inclusion of flexible regions to form dynamic nanostructures. These types of dynamic nanostructures are typically actuated via the addition DNA “fuel” strands that form new connections to reconfigure a structure, or via the selective removal of DNA components via strand displacement. The goal of this work is to enable novel actuation methods with distinct, and potentially faster, triggering mechanisms based on incorporating other nanomaterial components. While DNA origami has been used in combination with other nanomaterials such as gold nanoparticles there has yet to be a demonstration of nanoparticles used for the precise control of nanostructure actuation. Using a DNA origami hinge mechanism we have included single-stranded DNA overhangs extending from the arms, which bind to a gold nanoparticle to latch the hinge closed. By varying where the nanoparticle is incorporated (distance from the hinge vertex) and the nanoparticle size we have shown that the angular distributions of the hinge are highly controllable. In addition, tuning the nanoparticle binding affinity of the bottom arm relative to the top arm allows for actuation of the hinge via DNA melting without releasing the nanoparticle entirely, thereby enabling reversible temperature-based actuation. Particle binding and hinge actuation were monitored via a two color fluorescence quenching setup to reveal that the kinetics of actuation occur on the minute timescale. Future work will explore light-based actuation mediated by local plasmonic heating of the nanoparticles. We have also polymerized hinges into dynamic assemblies, which in combination with nanoparticle based actuation schemes will establish a basis for rapidly reconfigurable materials with future applications in biosensing, plasmonics, and bioenergetics.