Monitoring the Thiol/Thiophenol Molecule-Modulated Plasmon-Mediated Silver Oxidation with Dark-Field Optical Microscopy.

Surface plasmon can trigger or accelerate many photochemical reactions, especially useful in energy and environmental industries. Recently, molecular adsorption has proven effective in modulating plasmon-mediated photochemistry, however the realized chemical reactions are limited and the underlying mechanism is still unclear. Herein, by using in situ dark-field optical microscopy, the plasmon-mediated oxidative etching of silver nanoparticles (Ag NPs), a typical hot-hole-driven reaction, is monitored continuously and quantitatively. The presence of thiol or thiophenol molecules is found essential in the silver oxidation. In addition, the rate of silver oxidation is modulated by the choice of different thiol or thiophenol molecules. Compared with the molecules having electron donating groups, the ones having electron accepting groups accelerate the silver oxidation dramatically. The thiol/thiophenol modulation is attributed to the modulation of the charge separation between the Ag NPs and the adsorbed thiol or thiophenol molecules. This work demonstrates the great potential of molecular adsorption in modulating the plasmon-mediated photochemistry, which will pave a new way for developing highly efficient plasmonic photocatalysts.

Nanomedicine-based disulfiram and metal ion co-delivery strategies for cancer treatment.

Disulfiram (DSF) is a second-line drug for the clinical treatment of alcoholism and has long been proven to be safe for use in clinical practice. In recent years, researchers have discovered the cancer-killing activity of DSF, which is highly dependent on the presence of metal ions, particularly copper ions. Additionally, free DSF is highly unstable and easily degraded within few minutes in blood circulation. Therefore, an ideal DSF formulation should facilitate the co-delivery of metal ions and safeguard the DSF throughout its biological journey before reaching the targeted site. Extensive research have proved that nanotechnology based formulations can effectively realize this goal by strategic encapsulation therapeutic agents within nanoparticle. To be more specific, this is accomplished through precise delivery, coordinated release of metal ions at the tumor site, thereby amplifying its cytotoxic potential. Beyond traditional co-loading techniques, innovative approaches such as DSF-metal complex and metal nanomaterials, have also demonstrated promising results at the animal model stage. This review aims to elucidate the anticancer mechanism associated with DSF and its reliance on metal ions, as well as to provide a comprehensive overview of recent advances in the arena of nanomedicine based co-delivery strategies for DSF and metal ion in the context of cancer therapy.

Opsonization Inveigles Macrophages Engulfing Carrier-Free Bilirubin/JPH203 Nanoparticles to Suppress Inflammation for Osteoarthritis Therapy.

Osteoarthritis (OA) is a chronic inflammatory disease characterized by cartilage destruction, synovitis, and osteophyte formation. Disease-modifying treatments for OA are currently lacking. Because inflammation mediated by an imbalance of M1/M2 macrophages in the synovial cavities contributes to OA progression, regulating the M1 to M2 polarization of macrophages can be a potential therapeutic strategy. Basing on the inherent immune mechanism and pathological environment of OA, an immunoglobulin G-conjugated bilirubin/JPH203 self-assembled nanoparticle (IgG/BRJ) is developed, and its therapeutic potential for OA is evaluated. After intra-articular administration, IgG conjugation facilitates the recognition and engulfment of nanoparticles by the M1 macrophages. The internalized nanoparticles disassemble in response to the increased oxidative stress, and the released bilirubin (BR) and JPH203 scavenge reactive oxygen species (ROS), inhibit the nuclear factor kappa-B pathway, and suppress the activated mammalian target of rapamycin pathway, result in the repolarization of macrophages and enhance M2/M1 ratios. Suppression of the inflammatory environment by IgG/BRJ promotes cartilage protection and repair in an OA rat model, thereby improving therapeutic outcomes. This strategy of opsonization involving M1 macrophages to engulf carrier-free BR/JPH203 nanoparticles to suppress inflammation for OA therapy holds great potential for OA intervention and treatment.

Density-of-States Matching-Induced Ultrahigh Current Density and High-Humidity Resistance in a Simply Structured Triboelectric Nanogenerator.

Triboelectric nanogenerators (TENGs) can covert mechanical energy into electricity in a clean and sustainable manner. However, traditional TENGs are mainly limited by the low output current, and thus their practical applications are still limited. Herein, a new type of TENG is developed by using conductive materials as the triboelectric layers and electrodes simultaneously. Because of the matched density of states between the two triboelectric layers, this simply structured device reaches an open-circuit voltage of 1400 V and an ultrahigh current density of 1333 mA m-2 when poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film and copper (Cu) or aluminum (Al) foil are used as the triboelectric pair. The current density increases by nearly three orders of magnitude compared with traditional TENGs. More importantly, this device can work stably in high-humidity environments, which is always a big challenge for traditional TENGs. Surprisingly, this TENG can even perform well in the presence of water droplets. This work provides a new and effective strategy for constructing high-performance TENGs, which can be used in many practical applications in the near future.

Strong synergy between gold nanoparticles and cobalt porphyrin induces highly efficient photocatalytic hydrogen evolution.

The reaction efficiency of reactants near plasmonic nanostructures can be enhanced significantly because of plasmonic effects. Herein, we propose that the catalytic activity of molecular catalysts near plasmonic nanostructures may also be enhanced dramatically. Based on this proposal, we develop a highly efficient and stable photocatalytic system for the hydrogen evolution reaction (HER) by compositing a molecular catalyst of cobalt porphyrin together with plasmonic gold nanoparticles, around which plasmonic effects of localized electromagnetic field, local heating, and enhanced hot carrier excitation exist. After optimization, the HER rate and turn-over frequency (TOF) reach 3.21 mol g-1 h-1 and 4650 h-1, respectively. In addition, the catalytic system remains stable after 45-hour catalytic cycles, and the system is catalytically stable after being illuminated for two weeks. The enhanced reaction efficiency is attributed to the excitation of localized surface plasmon resonance, particularly plasmon-generated hot carriers. These findings may pave a new and convenient way for developing plasmon-based photocatalysts with high efficiency and stability.

Ultraviolet B radiation-induced JPH203-loaded keratinocyte extracellular vesicles exert etiological interventions for psoriasis therapy.

Psoriasis is a multifactorial immuno-inflammatory skin disease, characterized by keratinocyte hyperproliferation and aberrant immune activation. Although the pathogenesis is complex, the interactions among inflammation, Th17-mediated immune activation, and keratinocyte hyperplasia are considered to play a crucial role in the occurrence and development of psoriasis. Therefore, pharmacological interventions on the "inflammation-Th17-keratinocyte" vicious cycle may be a potential strategy for psoriasis treatment. In this study, JPH203 (a specific inhibitor of LAT1, which engulfs leucine to activate mTOR signaling)-loaded, ultraviolet B (UVB) radiation-induced, keratinocyte-derived extracellular vesicles (J@EV) were prepared for psoriasis therapy. The EVs led to increased interleukin 1 receptor antagonist (IL-1RA) content due to UVB irradiation, therefore not only acting as a carrier for JPH203 but also functioning through inhibiting the IL-1-mediated inflammation cascade. J@EV effectively restrained the proliferation of inflamed keratinocytes via suppressing mTOR-signaling and NF-κB pathway in vitro. In an imiquimod-induced psoriatic model, J@EV significantly ameliorated the related symptoms as well as suppressed the over-activated immune reaction, evidenced by the decreased keratinocyte hyperplasia, Th17 expansion, and IL17 release. This study shows that J@EV exerts therapeutic efficacy for psoriasis by suppressing LAT1-mTOR involved keratinocyte hyperproliferation and Th17 expansion, as well as inhibiting IL-1-NF-κB mediated inflammation, representing a novel and promising strategy for psoriasis therapy.

Preparation of Janus nanosheets composed of gold/palladium nanoparticles and reduced graphene oxide for highly efficient emulsion catalysis.

Interface/emulsion catalysis is an effective approach for many organic and inorganic chemical reactions. Positioning catalysts at the interface is essential for highly efficient interface/emulsion catalysis. The sheet-like Janus nanostructures may have great advantages in stabilizing emulsions and improving reaction efficiency. In this work, by using a simple emulsion reaction and photodeposition, we successfully prepare the Janus nanosheets with opposite sides composed of AuNPs/PdNPs and reduced graphene oxide (rGO) respectively, referred to as AuNP-rGO/PdNP-rGO Janus nanosheets. Due to the distinct hydrophilicities on opposite sides, the prepared Janus nanosheets demonstrate high efficiency in emulsion stabilization and emulsion catalysis. By introducing the prepared PdNP-rGO and AuNP-rGO Janus nanosheets in emulsion reactions, highly efficient hydrogenation of p-nitroanisole and photocatalytic degradation of Nile red are demonstrated. This work provides a simple and cost-effective method to prepare Janus nanosheets and realize highly efficient emulsion reactions, and this strategy can be extended to promote many other interface/emulsion reactions.

Molecular Cocatalyst of p-Mercaptophenylboronic Acid Boosts the Plasmon-Mediated Reduction of p-Nitrothiophenol.

Localized surface plasmon resonance (LSPR) has been demonstrated to be highly effective in the initialization or acceleration of chemical reactions because of its unique optical properties. However, because of the ultrashort lifetime (fs to ps) of plasmon-generated hot carriers, the potential of LSPR in photochemical reactions has not been fully exploited. Herein, we demonstrate an acceleration of the plasmon-mediated reduction of p-nitrothiophenol (PNTP) molecules on the surface of silver nanoparticles (AgNPs) with in situ Raman spectroscopy. p-Mercaptophenylboronic acid (PMPBA) molecules coadsorbed on AgNP surfaces act as a molecular cocatalyst in the plasmon-mediated reaction, resulting in a boosting of the PNTP reduction. This boosting is attributed to the improved transfer and separation of the plasmon-generated hot carriers at the interface of the AgNPs and coadsorbed PMPBA molecules. Our finding provides a highly simple, cost-effective, and highly effective strategy to promote plasmonic photochemistry by introducing a molecular cocatalyst, and this strategy can be extended to promote various plasmon-mediated reactions.

Simple, Skin-Attachable, and Multifunctional Colorimetric Sweat Sensor.

In situ analysis of sweat provides a simple, convenient, cost-effective, and noninvasive approach for the early diagnosis of physical illness in humans and is particularly useful in family care. In this study, a flexible and skin-attachable colorimetric sweat sensor for multiplexed analysis is developed using a simple, cost-effective, and convenient method. The obtained sweat sensor can be used to simultaneously detect glucose, lactate, urea, and pH value in sweat, as well as sweat loss and skin temperature. Only 2.5 µL of sweat is enough for the whole test, and the sweat loss and chemical-sensing results can be read out conveniently by naked eyes or a smartphone. In addition, body temperature can also be detected with an additional electrical circuit. Our sweat sensor provides a new, cost-effective, and convenient approach for in vitro diagnosis of multiple components in sweat, and the easy fabrication and cost-effectiveness make our sensor commercializable in the near future.

Direct Observation of the Light-Induced Exfoliation of Molybdenum Disulfide Sheets in Water Medium.

Single and a few atomic-layer molybdenum disulfide (MoS2) is a promising material in the fields of hydrogen generation, battery, supercapacitor, and environmental protection, owing to the outstanding electronic, optical, and catalytic properties. Although many approaches have been developed for exfoliation of MoS2 sheets, it is still essential to develop simple, convenient, and environmental friendly exfoliation methods. More importantly, the microscopic exfoliation process and the mechanism are still not clear, limiting a deeper understanding of the exfoliation. Herein, we develop a convenient and clean method for exfoliation of the 2H phase MoS2 (2H-MoS2) deposited on an indium tin oxide (ITO) surface. Importantly, the exfoliation process is observed directly and continuously under an optical microscope to reveal the detailed exfoliation process and mechanism. As illustrated, the light illumination triggers the exfoliation of the 2H-MoS2 sheets, and the presence of water is essential in this exfoliation process. The light intensity and wavelength, humidity, and bias all affect the exfoliation process obviously. The exfoliation is caused by the vaporization of the water molecules intercalated in 2H-MoS2 interlayers. By using this method, 2H-MoS2 nanosheets with different thicknesses are prepared on the ITO substrate, and microscopic catalysis mapping of the exfoliated sheets is demonstrated with single-molecule fluorescence microscopy, revealing that the prepared thin-layer 2H-MoS2 nanosheets show improved electrocatalysis activity (roughly 20 times). Our work will not only help deepen the understanding of exfoliation process of two-dimensional nanosheets but also provide an effective tool for the in situ study of various properties of the exfoliated sheets.

Synthesis of Thin Bi9 O7.5 S6 Nanosheets for Improved Photodetection in a Wide Wavelength Range.

Bismuth-based compounds possess layered structures with a variety of stacking modes, endowing the compounds with diverse properties. As one type of bismuth oxysulfides, Bi9 O7.5 S6 nanocrystals has great applications in photodetection; however, the responsivity of bulky Bi9 O7.5 S6 is limited due to the poor charge separation. Herein, single-crystalline Bi9 O7.5 S6 thin nanosheets are successfully synthesized by using a solvothermal method. The thickness of the obtained Bi9 O7.5 S6 nanosheets is down to 15 nm and can be easily tuned by varying the reaction period. Moreover, the Bi9 O7.5 S6 nanosheets show strong light absorption in the visible and near infrared range, making it a promising candidate in optoelectronics. As a demonstration, the thin Bi9 O7.5 S6 nanosheets are used as active layer in an optoelectronic device, which exhibits sensitive photoelectric response to light in a wide range of 400-800 nm. The responsivity of the device reaches up to 1140 µA W-1 , and the performance of the device is stable after long-period illumination. This work demonstrates a great potential of the thin Bi9 O7.5 S6 nanosheets in optoelectronic devices, and these nanosheets may also be extended to various optoelectronic applications.

Copper-catalyzed radical cascades of para-quinone methides with AIBN and H2O via α-cyanoalkylation by C-C bond cleavage: new access to benzofuran-2(3H)-ones.

We describe the first one-pot construction of a benzofuran-2(3H)-one scaffold via a radical cascade reaction of para-quinone methides with azodiisobutyronitrile and water. In the presence of CuI (20 mol%), this cascade proceeds smoothly through 1,6-conjugate addition/aromatization, α-cyanoalkylation by unstrained and non-polar C(aryl)-C(t-butyl) bond cleavage, and downstream cyano-insertion/cyclization/hydrolysis, which leads to cyano-containing benzofuran-2(3H)-ones with an excellent functional-group compatibility.