Dynamic DNA Nanodevices with Switchable Optical Properties

Advancements in DNA nanotechnology have opened up the ability to fabricate nanomaterials with dynamic properties for applications in optics, medicine, and electronics. Such properties are defined by precisely controlled arrangements of functional nanocomponents. However, there remains a continual challenge in gaining dynamic control of nanoscale materials. DNA-based self-assembly offers a promising approach to form switchable three-dimensional (3D) clusters and large-scale ordered nanostructures that can encapsulate, organize and manipulate various types of nanoscale objects through programmable interactions.<br/>Here we study the assembly, reconfiguration and optical response of a nanoscale device with stimuli-responsive and switchable properties. We utilized a 3D polyhedral DNA frame to establish a system that can switch between different conformations that allow for the manipulation of nanoparticles. Our previous studies have demonstrated that the optical output of a binary self-assembled system composed of gold nanoparticles (AuNP) and quantum dots depends on the interparticle separation distance. With this as a reference, we designed a structurally switchable 3D DNA frame for nanoparticle repositioning. By utilizing a DNA motif that acts as a manipulator, we show an ability to pass molecular information over a distance of tens of nanometers on a frame. We used this principle to investigate how this DNA device is able to direct nanoparticle reconfigurations and induce different optical responses. Interactions between the plasmonic and fluorescent particles were explored by testing various system designs. The structural reconfiguration of the system was examined by electron microscopy and small-angle X-ray scattering (SAXS), while spectroscopic measurements were applied to correlated optical responses with structural switching.