DNA-Nanotechnology-Enabled Chiral Plasmonics: From Static to Dynamic

Abstract

The development of DNA nanotechnology, especially the advent of DNA origami, has made DNA ideally suited to construct nanostructures with unprecedented complexity and arbitrariness. As a fully addressable platform, DNA origami can be used to organize discrete entities in space through DNA hybridization with nanometer accuracy. Among a variety of functionalized particles, metal nanoparticles such as gold nanoparticles (AuNPs) feature an important pathway to endow DNA-origami-assembled nanostructures with tailored optical functionalities. When metal particles are placed in close proximity, their particle plasmons, i.e., collective oscillations of conduction electrons, can be coupled together, giving rise to a wealth of interesting optical phenomena. Nevertheless, characterization methods that can read out the optical responses from plasmonic nanostructures composed of small metal particles, and especially can optically distinguish in situ their minute conformation changes, are very few. Circular dichroism (CD) spectroscopy has proven to be a successful means to overcome these challenges because of its high sensitivity in discrimination of three-dimensional conformation changes. In this Account, we discuss a variety of static and dynamic chiral plasmonic nanostructures enabled by DNA nanotechnology. In the category of static plasmonic systems, we first show chiral plasmonic nanostructures based on spherical AuNPs, including plasmonic helices, toroids, and tetramers. To enhance the CD responses, anisotropic gold nanorods with larger extinction coefficients are utilized to create chiral plasmonic crosses and helical superstructures. Next, we highlight the inevitable evolution from static to dynamic plasmonic systems along with the fast development of this interdisciplinary field. Several dynamic plasmonic systems are reviewed according to their working mechanisms. We first elucidate a reconfigurable plasmonic cross structure that can execute DNA-regulated conformational changes on the nanoscale. Hosted by a reconfigurable DNA origami template, the plasmonic cross can be switched between a chiral locked state and an achiral relaxed state through toehold-mediated strand displacement reactions. This reconfigurable nanostructure can also be modified in response to light stimuli, leading to a noninvasive, waste-free, and all-optically controlled system. Taking one step further, we show that selective manipulations of individual structural species coexisting in one ensemble can be achieved using pH tuning of reconfigurable plasmonic nanostructures in a programmable manner. Finally, we describe an alternative to achieving dynamic plasmonic systems by driving AuNPs directly on origami. Such plasmonic walkers, inspired by the biological molecular motors in living cells, can generate dynamic CD responses when carrying out directional, progressive, and reverse nanoscale walking on DNA origami. We envision that the combination of DNA nanotechnology and plasmonics will open an avenue toward a new generation of functional plasmonic...

Dynamic Nanostructures from DNA‐Coupled Molecules, Polymers, and Nanoparticles

“…Researchers have also designed DNA‐conjugated nanomaterials that are capable of on‐demand cellular uptake and drug release in response to light, heat, pH, and DNA binding, which can be developed as key components in smart delivery systems. While there remain critical challenges to be solved before they can be implemented in practical applications, the dynamic DNA‐based assembly has already been utilized for fundamental studies of interacting molecules and nanoparticles . The development of dynamic DNA nanostructures is just beginning and we anticipate that with brilliant new design it can solve important questions in materials science and biomedical applications.…”

“…We further discuss their potential applications and present future perspectives. Readers are also directed to recent reviews on dynamic nanostructures fabricated with DNA scaffolds, DNA‐based hydrogels, and 2D films to gain further insights into the new possibilities in this exciting research area.…”

Controlling Chirality across Length Scales using DNA

“…Dynamic structures with chiro‐optical effects were also investigated, where the overall shape of the chiral nanostructures changed in response to a stimulus, where a component of the nanostructures was removed or replaced, or the orientation of the structures with respect to the polarized incident light was sequentially altered …”

An NIR‐Responsive DNA‐Mediated Nanotetrahedron Enhances the Clearance of Senescent Cells

“…By virtue of these characteristics, nanoassemblies have been applied for various fields of medicine, including biosensing, bioimaging, disease diagnosis and treatment 1–7. Due to excellent in vivo stability, significant progress has been made in the self‐assembly of discrete nanoparticles with a DNA frame 8–13. These well‐defined nanoassemblies could be used as an effective nanocarrier for the delivery of small molecules or some proteins into target areas 14–16.…”