Strong Light-Matter Interactions in Chiral Plasmonic-Excitonic Systems Assembled on DNA Origami.

The exploitation of strong light-matter interactions in chiral plasmonic nanocavities may enable exceptional physical phenomena and lead to potential applications in nanophotonics, information communication, etc. Therefore, a deep understanding of strong light-matter interactions in chiral plasmonic-excitonic (plexcitonic) systems constructed by a chiral plasmonic nanocavity and molecular excitons is urgently needed. Herein, we systematically studied the strong light-matter interactions in gold nanorod-based chiral plexcitonic systems assembled on DNA origami. Rabi splitting and anticrossing behavior were observed in circular dichroism spectra, manifesting chiroptical characteristic hybridization. The bisignate line shape of the circular dichroism (CD) signal allows the accurate discrimination of hybrid modes. A large Rabi splitting of ∼205/∼199 meV for left-handed/right-handed plexcitonic nanosystems meets the criterion of strong coupling. Our work deepens the understanding of light-matter interactions in chiral plexcitonic nanosystems and will facilitate the development of chiral quantum optics and chiroptical devices.

A Tubular DNA Nanodevice as a siRNA/Chemo-Drug Co-delivery Vehicle for Combined Cancer Therapy.

Using the DNA origami technique, we constructed a DNA nanodevice functionalized with small interfering RNA (siRNA) within its inner cavity and the chemotherapeutic drug doxorubicin (DOX), intercalated in the DNA duplexes. The incorporation of disulfide bonds allows the triggered mechanical opening and release of siRNA in response to intracellular glutathione (GSH) in tumors to knockdown genes key to cancer progression. Combining RNA interference and chemotherapy, the nanodevice induced potent cytotoxicity and tumor growth inhibition, without observable systematic toxicity. Given its autonomous behavior, exceptional designability, potent antitumor activity and marked biocompatibility, this DNA nanodevice represents a promising strategy for precise drug design for cancer therapy.

Shape Complementarity Modulated Self-Assembly of Nanoring and Nanosphere Hetero-nanostructures.

Shape complementarity is of paramount importance in molecular recognition, but has rarely been adopted in the self-assembly of colloidal particles, especially in the case of nanoparticles of different shapes. Here, we demonstrated a simple, yet powerful strategy for fabricating gold nanoring-based heterogeneous nanostructures (AuNR-HNs) with well-defined geometries and high yield. The assembly of various geometries of AuNR-HNs is modulated by the shape complementarity of plasmonic nanorings and nanospheres. We also present experimental evidence of dark quadrupolar ring mode excitation in AuNR-HNs through single-particle optical measurements. Our strategy will be beneficial in the study of nanoparticle assembly, photonic element interaction, and the development of plasmon-based optical devices.

Fabrication of Metal Nanostructures on DNA Templates.

Metal nanoarchitectures fabrication based on DNA assembly has attracted a good deal of attention. DNA nanotechnology enables precise organization of nanoscale objects with extraordinary structural programmability. The spatial addressability of DNA nanostructures and sequence-dependent recognition allow functional elements to be precisely positioned; thus, novel functional materials that are difficult to produce using conventional methods could be fabricated. This review focuses on the recent development of the fabrication strategies toward manipulating the shape and morphology of metal nanoparticles and nanoassemblies based on the rational design of DNA structures. DNA-mediated metallization, including DNA-templated conductive nanowire fabrication and sequence-selective metal deposition, etc., is briefly introduced. The modifications of metal nanoparticles (NPs) with DNA and subsequent construction of heterogeneous metal nanoarchitectures are highlighted. Importantly, DNA-assembled dynamic metal nanostructures that are responsive to different stimuli are also discussed as they allow the design of smart and dynamic materials. Meanwhile, the prospects and challenges of these shape-and morphology-controlled strategies are summarized.