Light‐Responsive Dynamic DNA‐Origami‐Based Plasmonic Assemblies

Controlling Chiroptical Responses via Chemo-Mechanical Deformation of DNA Origami Structures

DNA origami-based templates have been widely used to fabricate chiral plasmonic metamaterials due to their precise control of the placement of nanoparticles (NPs) in a desired configuration. However, achieving various chiroptical responses inevitably requires a change in the structure of DNA origami-based templates or binding sites on them, leading to the use of significantly different sets of DNA strands. Here, we propose an approach to controlling various chiroptical responses with a single DNA origami design using its chemo-mechanical deformation induced by DNA intercalators. The chiroptical response could be finely tuned by altering the concentration of intercalators only. The silver (Ag) enhancement was used to amplify the chiroptical signal by enlarging NPs and to maintain it by stiffening the template DNA structure. Furthermore, the sensitivity in the chiroptical signal change to the concentration of intercalators could be modulated by the type of intercalator, the mixture of two intercalators, and the stiffness of DNA origami structures. This approach would be useful in a variety of optical applications that require programmed spatial modification of chiroptical responses.

Recent Advances in DNA Origami-Engineered Nanomaterials and Applications

DNA nanotechnology is a unique field, where physics, chemistry, biology, mathematics, engineering, and materials science can elegantly converge. Since the original proposal of Nadrian Seeman, significant advances have been achieved in the past four decades. During this glory time, the DNA origami technique developed by Paul Rothemund further pushed the field forward with a vigorous momentum, fostering a plethora of concepts, models, methodologies, and applications that were not thought of before. This review focuses on the recent progress in DNA origami-engineered nanomaterials in the past five years, outlining the exciting achievements as well as the unexplored research avenues. We believe that the spirit and assets that Seeman left for scientists will continue to bring interdisciplinary innovations and useful applications to this field in the next decade.

Multiple Wavelength Photopolymerization of Stable Poly(Catecholamines)-DNA Origami Nanostructures

The synthesis of multicomponent polymer hybrids with nanometer precision is chemically challenging in the bottom-up synthesis of complex nanostructures. Here, we leverage the fidelity of the DNA origami technique to install a multiple wavelength responsive photopolymerization system with nanometer resolution. By precisely immobilizing various photosensitizers on the origami template, which are only activated at their respective maximum wavelength, we can control sequential polymerization processes. In particular, the triggered photosensitizers generate reactive oxygen species that in turn initiate the polymerization of the catecholamines dopamine and norepinephrine. We imprint polymeric layers at designated positions on DNA origami, which modifies the polyanionic nature of the DNA objects, thus promoting their uptake into living cells while preserving their integrity. Our herein proposed method provides a rapid platform to access complex 3D nanostructures by customizing material and biological interfaces.

Hysteresis Nanoarchitectonics with Chiral Gel Fibers and Achiral Gold Nanospheres for Reversible Chiral Inversion

Intelligent control over the handedness of circular dichroism (CD) is of special significance in self-organized biological and artificial systems. Herein, we report a chiral organic molecule (R1) containing a disulfide unit self-assembles into M-type helical fibers gels, which undergoes chirality inversion by incorporating gold nanospheres due to the formation of Au-S bonds between R1 and gold nanospheres. Upon heating at 80oC, the aggregation of gold nanospheres results in a disappearance of the Au-S bond, allowing the reversible switching back to M-type helical fibers. The original chirality of M-type fibers could also be retained by adding anisotropic gold nanorods. A series of characterization methods, involving CD, Raman, Infrared spectroscopy, electric microscopy, and small-angle X-ray scattering (SAXS) measurements were used to investigate the mechanism of chiral evolutions. Our results provide a facile way of fabricating hysteresis nanoarchitectonics to achieve dynamic supramolecular chirality using inorganic metallic nanoparticles.

Light-Switchable Buffers

A visible light-switchable buffer system based on a merocyanine photoacid is presented. Para-substitution of the indolium side with a methoxy group affords a compound suitable for making hydrolytically stable aqueous buffers whose pH can be tuned between 7 and 4 using 500 nm light.