Indium tin oxide (ITO) has been the most widely studied conducting metal oxide and serves as the best candidate for proof-of-concept experiments in the field of surface plasmon resonance and studies of electric field confinement and manipulation. ITO is chemically stable and relatively easy to sputter. In this report, arrays of ITO nanostructures were produced using nanosphere lithography, which was originally developed for plasmonic applications involving noble metals. However, the experiments presented here show that patterned ITO with similar size and shape to noble metals has an observed extinction that corresponds to the epsilon-near-zero mode. The carrier density of ITO nanostructure can be controlled by the postdeposition annealing process. Thus, one can prove that the optical signals on the surface are those of the ITO nanostructure by reversible on/off switching of the capacitive plasmon resonance by annealing the surfaces successively in forming gas (N2/H2) and in air. Thus, using conducting metal oxides confident of the electric field is possible not only along the z-axis perpendicular to the thin film but within the plane of the film as well.

Dynamic manipulation of supramolecular self‐assembled structures is achieved irreversibly or under non‐physiological conditions, thereby limiting their biomedical, environmental, and catalysis applicability. In this study, microgels composed of azobenzene derivatives stacked via π–cation and π–π interactions are developed that are electrostatically stabilized with Arg–Gly–Asp (RGD)‐bearing anionic polymers. Lateral swelling of RGD‐bearing microgels occurs via cis‐azobenzene formation mediated by near‐infrared‐light‐upconverted ultraviolet light, which disrupts intermolecular interactions on the visible‐light‐absorbing upconversion‐nanoparticle‐coated materials. Real‐time imaging and molecular dynamics simulations demonstrate the deswelling of RGD‐bearing microgels via visible‐light‐mediated trans‐azobenzene formation. Near‐infrared light can induce in situ swelling of RGD‐bearing microgels to increase RGD availability and trigger release of loaded interleukin‐4, which facilitates the adhesion structure assembly linked with pro‐regenerative polarization of host macrophages. In contrast, visible light can induce deswelling of RGD‐bearing microgels to decrease RGD availability that suppresses macrophage adhesion that yields pro‐inflammatory polarization. These microgels exhibit high stability and non‐toxicity. Versatile use of ligands and protein delivery can offer cytocompatible and photoswitchable manipulability of diverse host cells.

Sub-10 nm-sized bright red-emitting YOF:Yb,Er/YOF core/shell upconversion nanophosphors are successfully synthesized from ultrasmall tetrahedral-shaped YOF:Yb,Er cores with well-defined crystallographic facets.