Gold Nanoparticles Downregulate Interleukin‐1β‐Induced Pro‐Inflammatory Responses

Interleukin 1 beta (IL‐1β)‐dependent inflammatory disorders, such as rheumatoid arthritis and psoriasis, pose a serious medical burden worldwide, where patients face a lifetime of illness and treatment. Organogold compounds have been used since the 1930s to treat rheumatic and other IL‐1β‐dependent diseases and, though their mechanisms of action are still unclear, there is evidence that gold interferes with the transmission of inflammatory signalling. Here we show for the first time that citrate‐stabilized gold nanoparticles, in a size dependent manner, specifically downregulate cellular responses induced by IL‐1β both in vitro and in vivo. Our results indicate that the anti‐inflammatory activity of gold nanoparticles is associated with an extracellular interaction with IL‐1β, thus opening potentially novel options for further therapeutic applications.     

Many‐Body Complexes in 2D Semiconductors

2D semiconductors such as transition metal dichalcogenides (TMDs) and black phosphorus (BP) are currently attracting great attention due to their intrinsic bandgaps and strong excitonic emissions, making them potential candidates for novel optoelectronic applications. Optoelectronic devices fabricated from 2D semiconductors exhibit many‐body complexes (exciton, trion, biexciton, etc.) which determine the materials optical and electrical properties. Characterization and manipulation of these complexes have become a reality due to their enhanced binding energies as a direct result from reduced dielectric screening and enhanced Coulomb interactions in the 2D regime. Furthermore, the atomic thickness and extremely large surface‐to‐volume ratio of 2D semiconductors allow the possibility of modulating their inherent optical, electrical, and optoelectronic properties using a variety of different environmental stimuli. To fully realize the potential functionalities of these many‐body complexes in optoelectronics, a comprehensive understanding of their formation mechanism is essential. A topical and concise summary of the recent frontier research progress related to many‐body complexes in 2D semiconductors is provided here. Moreover, detailed discussions covering the aspects of fundamental theory, experimental investigations, modulation of properties, and optoelectronic applications are given. Lastly, personal insights into the current challenges and future outlook of many‐body complexes in 2D semiconducting materials are presented.     

Human‐Finger Electronics Based on Opposing Humidity‐Resistance Responses in Carbon Nanofilms

Carbon nanomaterials have excellent humidity sensing properties. Here, it is demonstrated that multiwalled carbon‐nanotube (MWCNT)‐ and reduced‐graphene‐oxide (rGO)‐based conductive films have opposite humidity/electrical resistance responses: MWCNTs increase their electrical resistance (positive response) and rGOs decrease their electrical resistance (negative response). The authors propose a new phenomenology that describes a “net”‐like model for MWCNT films and a “scale”‐like model for rGO films to explain these behaviors based on contributions from junction resistances (at interparticle junctions) and intrinsic resistances (of the particles). This phenomenology is accordingly validated via a series of experiments, which complement more classical models based on proton conductivity. To explore the practical applications of the converse humidity/resistance responses, a humidity‐insensitive MWCNT/rGO hybrid conductive films is developed, which has the potential to greatly improve the stability of carbon‐based electrical device to humidity. The authors further investigate the application of such films to human‐finger electronics by fabricating transparent flexible devices consisting of a polyethylene terephthalate substrate equipped with an MWCNT/rGO pattern for gesture recognition, and MWCNT/rGO/MWCNT or rGO/MWCNT/rGO patterns for 3D noncontact sensing, which will be complementary to existing 3D touch technology.     

Bridging Systemic Immunity with Gastrointestinal Immune Responses via Oil‐in‐Polymer Capsules

As peripheral lymphocytes are typically excluded from the gastrointestinal lymph tissues, current parenteral vaccinations fail to simultaneously induce systemic and mucosal responses. To break the natural barrier, “immunoticket” capsules are developed and heralded, which are designed with positive charged shells and oily core to spatiotemporally deliver antigens and all‐trans retinoic acid (RA). After intramuscular vaccinations, these capsules function as an immunoticket to cultivate peripheral dendritic cells (DCs) with gut‐homing receptors (CCR9). By hitchhiking on the concentration gradient of the CC‐motif chemokine ligand 25 (CCL25), the primed DCs would home to the gut associated lymphoid tissues (GALTs) and induce antigen‐specific IgA secretion and T cell engagements. Compared with the currently employed RA‐involving formulations, the immunoticket capsules stimulate enhanced RA‐mediated gut‐tropism by mounting the inflammatory innate immunity. Through controlling the RA payload, the potential regulatory T cell engagement is circumvented. In ovalbumin (OVA) and EV71 vaccinations, the immunoticket capsules induce potent serum IgG titer and antigen‐specific cytotoxic T cells in the peripheral lymph tissues, as well as robust IgA secretion and T cell engagements on gastrointestinal sites. The data suggest the potential of the immunotickets to serve as a facile, effective, and safe strategy to provide comprehensive immune responses against gastrointestinal infections and diseases     

Quasi‐static and Impact Responses of Multi‐layered Corrugated Paperboard Cushion by Virtual Mass Method

Quasi‐static compressive and impact behaviours of multi‐layered corrugated paperboard (MLCP) cushioning structure were analysed by a recently proposed virtual mass method. First, virtual mass method was applied and verified analytically to solve quasi‐static compressive responses for representative two‐layer corrugated paperboard cushioning structure. The results show that the two layers in the cushioning structure reach the buckling state in chronological order because of the existence of the small perturbations triggered by inertial force related to virtual mass, which leads to the two typical stress peaks in stress–strain curves. Second, the quasi‐static compressive behaviours of MLCP cushioning structure were further studied numerically, showing that the buckling order of multi‐layer cushioning structure depends on virtual mass, but the stress–strain curves remain unchanged when the virtual mass is smaller than some certain value. Finally, quasi‐static and dynamic impact tests of MLCP cushioning structure composed of C‐flute corrugated paperboard were carried out to further validate the capacity of the virtual mass method to describe layer‐wise collapse mechanism given the constitutive relationship of the monolayer corrugated paperboard. Copyright © 2014 John Wiley & Sons, Ltd.     

Artificial Soft Elastic Media with Periodic Hard Inclusions for Tailoring Strain‐Sensitive Thin‐Film Responses

Engineering the coupling behavior between a functional thin film and a soft substrate provides an attractive pathway for controlling various properties of thin‐film materials. However, existing studies mostly rely on uniform deformation of the substrate, and the effect of well‐regulated and nonuniform strain distributions on strain‐sensitive thin‐film responses still remains elusive. Herein, artificially strain‐regulated elastic media are presented as a novel platform for tailoring strain‐sensitive thin‐film responses. The proposed artificial soft elastic media are composed of embedded arrays of inkjet‐printed polymeric strain modulators that exhibit a high modulus contrast with respect to that of the soft matrix. This strain‐modulating lattice induces spatially regulated strain distributions based on localized strain‐coupling. Controlling the structural parameters and lattice configurations of the media leads to spatial modulation of the microscopically localized as well as macroscopically accumulated strain profiles. Uniform thin films coupled to these media undergo artificially tailored deformation through lattice‐like strain‐coupled pathways. The resulting phenomena yield programmable strain‐sensitive responses such as spatial arrangement of ternary‐state surface wrinkles and stepwise tuning of piezoresistive responses. This work will open a new avenue for addressing the issue of controlling strain‐sensitive thin‐film properties through structural engineering of artificial soft elastic media.     

Ovarian Dysfunction Induced by Chronic Whole‐Body PM2.5 Exposure

Fine particulate matter (PM2.5) pollution arouses public health concerns over the world. Increasing epidemiologic evidence suggests that exposure to ambient airborne PM2.5 increases the risk of female infertility. However, relatively few studies have systematically explored the harmful effect of chronic PM2.5 exposure on ovarian function and the underlying mechanisms. In this study, female C57BL/6J mice are exposed to filtered air or urban airborne PM2.5 for 4 months through a whole‐body exposure system. It is found that PM2.5 exposure significantly caused the alteration of estrus cycles, reproductivity, hormone levels, and ovarian reserve. The granulosa cell apoptosis via the mitochondria dependent pathway contributes to the follicle atresia. With RNA‐sequencing technique, the differentially expressed genes induced by PM2.5 exposure are mainly enriched in ovarian steroidogenesis, reactive oxygen species and oxidative phosphorylation pathways. Furthermore, it is found that increased PM2.5 profoundly exacerbated ovarian oxidative stress and inflammation in mice through the NF‐κB/IL‐6 signaling pathway. Notably, dietary polydatin (PD) supplement has protective effect in mice against PM2.5‐induced ovarian dysfunction.These striking findings demonstrate that PM2.5 and/or air pollution is a critical factor for ovarian dysfunction through mitochondria‐dependent and NF‐κB/IL‐6‐mediated pathway, and PD may serve as a pharmaceutic candidate for air pollution‐associated ovarian dysfunction.     

Template‐Free Growth of Well‐Ordered Silver Nano Forest/Ceramic Metamaterial Films with Tunable Optical Responses

Currently, the limitations of conventional methods for fabricating metamaterials composed of well‐aligned nanoscale inclusions either lack the necessary freedom to tune the structural geometry or are difficult for large‐area synthesis. In this Communication, the authors propose a fabrication route to create well‐ordered silver nano forest/ceramic composite single‐layer or multi‐layer vertically stacked structures, as a distinctive approach to make large‐area nanoscale metamaterials. To take advantage of direct growth, the authors fabricate single‐layer nanocomposite films with a well‐defined sub‐5 nm interwire gap and an average nanowire diameter of ≈3 nm. Further, artificially constructed multilayer metamaterial films are easily fabricated by vertical integration of different single‐layer metamaterial films. Based upon the thermodynamics as well as thin film growth dynamics theory, the growth mechanism is presented to elucidate the formation of such structure. Intriguing steady and transient optical properties in these assemblies are demonstrated, owing to their nanoscale structural anisotropy. The studies suggest that the self‐organized nanocomposites provide an extensible material platform to manipulate optical response in the region of sub‐5 nm scale.     

Characterization of Differential Toll‐like Receptor Responses below the Optical Diffraction Limit

Many membrane receptors are recruited to specific cell surface domains to form nanoscale clusters upon ligand activation. This step appears to be necessary to initiate cell signaling, including pathways in innate immune system activation. However, virulent pathogens such as Yersinia pestis (the causative agent of plague) are known to evade innate immune detection, in contrast to similar microbes (such as Escherichia coli) that elicit a robust response. This disparity has been partly attributed to the structure of lipopolysaccharides (LPS) on the bacterial cell wall, which are recognized by the innate immune receptor TLR4. It is hypothesized that nanoscale differences exist between the spatial clustering of TLR4 upon binding of LPS derived from Y. pestis and E. coli. Although optical imaging can provide exquisite details of the spatial organization of biomolecules, there is a mismatch between the scale at which receptor clustering occurs (<300 nm) and the optical diffraction limit (>400 nm). The last decade has seen the emergence of super‐resolution imaging methods that effectively break the optical diffraction barrier to yield truly nanoscale information in intact biological samples. This study reports the first visualizations of TLR4 distributions on intact cells at image resolutions of <30 nm using a novel, dual‐color stochastic optical reconstruction microscopy (STORM) technique. This methodology permits distinction between receptors containing bound LPS from those without at the nanoscale. Importantly, it is also shown that LPS derived from immunostimulatory bacteria result in significantly higher LPS–TLR4 cluster sizes and a nearly twofold greater ligand/receptor colocalization as compared to immunoevading LPS.