Optoelectronic effects differentiating absorption of right and left circularly polarized photons in thin films of chiral materials are typically prohibitively small for their direct photocurrent ...observation. Chiral metasurfaces increase the electronic sensitivity to circular polarization, but their out-of-plane architecture entails manufacturing and performance trade-offs. Here, we show that nanoporous thin films of chiral nanoparticles enable high sensitivity to circular polarization due to light-induced polarization-dependent ion accumulation at nanoparticle interfaces. Self-assembled multilayers of gold nanoparticles modified with L-phenylalanine generate a photocurrent under right-handed circularly polarized light as high as 2.41 times higher than under left-handed circularly polarized light. The strong plasmonic coupling between the multiple nanoparticles producing planar chiroplasmonic modes facilitates the ejection of electrons, whose entrapment at the membrane-electrolyte interface is promoted by a thick layer of enantiopure phenylalanine. Demonstrated detection of light ellipticity with equal sensitivity at all incident angles mimics phenomenological aspects of polarization vision in marine animals. The simplicity of self-assembly and sensitivity of polarization detection found in optoionic membranes opens the door to a family of miniaturized fluidic devices for chiral photonics.
Type I interferon (IFN) is a common therapy for autoimmune and inflammatory disorders, yet the mechanisms of action are largely unknown. Here we showed that type I IFN inhibited interleukin-1 (IL-1) ...production through two distinct mechanisms. Type I IFN signaling, via the STAT1 transcription factor, repressed the activity of the NLRP1 and NLRP3 inflammasomes, thereby suppressing caspase-1-dependent IL-1β maturation. In addition, type I IFN induced IL-10 in a STAT1-dependent manner; autocrine IL-10 then signaled via STAT3 to reduce the abundance of pro-IL-1α and pro-IL-1β. In vivo, poly(I:C)-induced type I IFN diminished IL-1β production in response to alum and Candida albicans, thus increasing susceptibility to this fungal pathogen. Importantly, monocytes from multiple sclerosis patients undergoing IFN-β treatment produced substantially less IL-1β than monocytes derived from healthy donors. Our findings may thus explain the effectiveness of type I IFN in the treatment of inflammatory diseases but also the observed “weakening” of the immune system after viral infection.
► Type I IFN inhibits NLRP1b and NLRP3 inflammasomes in a STAT1-dependent manner ► Type I IFN decreases the amounts of pro-IL-1α and pro-IL-1β in a STAT3-dependent manner ► Monocytes from MS patients undergoing IFN-β treatment show impaired IL-1β secretion
The concentration and manipulation of light in the nanoscale range are fundamental to nanophotonic research. Plasmonic nanoparticles can localize electromagnetic waves within subdiffraction volumes, ...but they also undergo large Joule losses and inevitable thermal heating. Subwavelength dielectric nanoparticles have emerged as a new class of photonic building blocks that enhance light–matter interactions within nanometric volumes. These nanoparticles exhibit strong electric and magnetic responses with negligible energy dissipation. In recent decades, the design of efficient dielectric nanoresonators has seen tremendous progress. In this review, recent theoretical and experimental advances in characterizing the optical properties of dielectric nanoparticles, from resonant single‐particle scattering characteristics to multimodal interference in complex particle assemblies, are discussed. Specific attention is paid to novel strategies employed to manipulate far‐field Mie‐type scattering, enhance local electromagnetic field, and boost magnetic resonance, as well as ultimately achieve Fano‐like resonance, unidirectional scattering (Kerker conditions), and photon waveguide. A collection of emerging applications of dielectric nanoparticles is also highlighted and the fundamental prospects of designing all‐dielectric/metallic–dielectric photonic nanostructures are considered, particularly those of functional dielectric materials and all‐dielectric 3D assemblies.
Subwavelength dielectric particles have emerged as a new class of photonic building blocks that enable enhanced light–matter interactions within nanometric volumes. This review highlights recent theoretical and experimental advances that have fostered the ability to shape the optical properties of dielectric nanoparticles, from resonant single‐particle scattering characteristics to the multimodal interferences of complex particle dispositions.
Chiral inorganic superstructures have received considerable interest due to the chiral communication between inorganic compounds and chiral organic additives. However, the demanding fabrication and ...complex multilevel structure seriously hinder the understanding of chiral transfer and self‐assembly mechanisms. Herein, we use chiral CuO superstructures as a model system to study the formation process of hierarchical chiral structures. Based on a simple and mild synthesis route, the time‐resolved morphology and the in situ chirality evolution could be easily followed. The morphology evolution of the chiral superstructure involves hierarchical assembly, including primary nanoparticles, intermediate bundles, and superstructure at different growth stages. Successive redshifts and enhancements of the CD signal support chiral transfer from the surface penicillamine to the inorganic superstructure. Full‐field electro‐dynamical simulations reproduced the structural chirality and allowed us to predict its modulation. This work opens the door to a large family of chiral inorganic materials where chiral molecule‐guided self‐assembly can be specifically designed to follow a bottom‐up chiral transfer pathway.
For inorganic material self‐assembly, chiral communication generally aims at transferring and amplifying chirality from the molecules to the superstructure. The demanding fabrication and complex structure seriously hinder understanding the mechanism of chiral transfer and superstructure formation. In this work, we use a simple and mild synthesis method to demonstrate the evolution of the morphology and chirality of hierarchical superstructures.
Operating photo‐induced reactions exclusively on catalyst surfaces while not exploiting the full catalyst volume generates a major footprint penalty for the photocatalytic reactor and leads to an ...inefficient use of the catalytic material. Photonic investigations clearly show that the solid foams have a strongly multidiffusive character, with photons being significantly trapped within the sample cores while addressing a photon mean free path lt = 20.1 ± 1.3 µm. This 3D process both greatly limits back‐reactions and promotes outstanding selectivity toward methane (around 80%) generation, and even ethane (around 18%) through C‐C coupling reaction, with residual carbon monoxide and dihydrogen contents (around 2%). Silica–titania TiO2@Si(HIPE) self‐standing macrocellular catalysts lead to optimal efficient thicknesses up to 20 times those of powders, thereby enhancing the way for real 3D‐photodriven catalytic processes above the millimeter scale and up to a 6 mm thickness. A rather simple Langmuir–Hinshelwood based kinetic model is proposed which highlights the strong dependence of photocatalytic reaction rates on light scattering and the crucial role on oxidation back‐reactions. In addition, a strong correlation between light attenuation coefficient and photon mean free path and median pore aperture diameter is demonstrated, offering thus a tool for photocatalytic behavior prediction.
Novel TiO2@Si(HIPE) monolithic macrocellular foams offer a path for real 3D photodriven CO2 conversion at the millimeter thickness length scale, a configuration where “thicker is better” appears as a new paradigm. The light trapping scenario and the associated photoinduced electron within the foams both limit back‐reactions and promote outstanding selectivity toward methane, as well as ethane generation through the C‐C coupling reaction.
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