A dual S-scheme TiO2@In2Se3@Ag3PO4 heterojunction for efficient photocatalytic CO2 reduction

The excellent photoresponse of semiconductors enables them to be promising photocatalysts for CO₂ reduction, but practical application is hampered by fast recombination of photogenerated carriers, low CO₂ capture capacity and poor stability. Herein, mesoporous hollow nanospheres of a dual S-scheme titanium dioxide@indium selenide@silver phosphate (TiO₂@In₂Se₃@Ag₃PO₄) heterojunction with a large specific surface area are designed and synthesized. The products of photocatalytic CO₂ reduction are CH₄, CH₃OH and CO with yields of 3.98, 4.32 and 8.2 μmol g^-1 h^-1, respectively, and the photocatalysts exhibit excellent cycle performance. The excellent photocatalytic performance is attributed to the large specific surface area of the samples and the construction of dual S-scheme heterojunctions. The large specific surface area can provide sufficient active sites for photocatalytic activity. Simultaneously, the built-in electric field (IEF) in the dual S-scheme exposed to light can facilitate the migration of photogenerated electrons from the CB of the oxidation photocatalyst (OP) to the VB of the reduction semiconductor (RP), where they recombine with the photogenerated holes on the VB of the RP, leaving behind photogenerated carriers with high redox ability for photocatalytic activity. This work provides new insights into the mechanism and design of highly efficient heterojunction photocatalysts for CO₂ reduction.

Ambipolar steep-slope nanotransistors with Janus MoSSe/graphene heterostructures

The transfer characteristics and switching mechanism of the steep-slope transistor composed of the graphene/Janus MoSSe heterostructure are investigated by quantum transport calculation. The Schottky barrier height at the Gr/SMoSe interface and tunneling width between the channel and drain can be tuned by the gate voltage, so that the device exhibits ambipolar switching with two minima in the subthreshold swing slope. 34 and 29 mV decade^-1subthreshold swings can be achieved and the on/off ratios are over 10⁶and 10⁸for the different switching mechanisms. The device provides a solution and guidance for the future design of low-power, high-performance devices.

Design and Properties of Antimicrobial Biomaterials Surfaces

Emergence of antibiotic-resistance pathogens has caused serious health issues and if the current trend is to continue, treatment of infection will become complicated and even unsuccessful due to new antimicrobial resistance (AMR). Therefore, there is a global drive to identify new methods to treat infection and develop better antibacterial materials and therapy. Although new and more potent antibiotics have aided the fight against microbes, they only offer a temporary solution because future bacteria strains may become resistant to these antibiotics and drugs. Recently, application of non-biological methods such electrical currents and photothermal/dynamic therapies to kill bacteria, reveals new approaches to design antimicrobial biomaterials, as complications stemming from drug-resistant bacteria can be obviated. Furthermore, recent research has focused on mimicking the surface patterns on plants and insects such as lotus leaves and dragonfly wings. Bio-inspired micro/nano patterns have been replicated on a variety of biomaterials to improve the bacterial resistance and other properties with good success. This is an exciting research area with immense practical and clinical potentials. In this review, recent advances in the application of chemical/biological approaches to combat bacterial infection and AMR are summarized and the related mechanisms are discussed. This article is protected by copyright. All rights reserved.

Probiotic-based nanoparticles for targeted microbiota modulation and immune restoration in bacterial pneumonia

While conventional bacterial pneumonia mainly centralizes avoidance of bacterial colonization, it remains unclear how to restore the host immunity for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia. Here, probiotic-based nanoparticles of OASCLR were formed by coating chitosan, hyaluronic acid and ononin on living Lactobacillus rhamnosus. OASCLR nanoparticles could effectively kill various clinic common pathogens and antibacterial efficiency was >99.97%. Importantly, OASCLR could modulate lung microbiota, increasing the overall richness and diversity of microbiota by decreasing pathogens and increasing probiotic and commensal bacteria. Additionally, OASCLR could target inflammatory macrophages by the interaction of OASCLR with the macrophage binding site of CD44 and alleviate overactive immune responses for hyperactive immunocompetent pneumonia. Surprisingly, OASCLR could break the state of the macrophage's poor phagocytic ability by upregulating the expression of the extracellular matrix assembly, immune activation and fibroblast activation in immunocompromised pneumonia. The macrophage's phagocytic ability was increased from 2.61% to 12.3%. Our work provides a potential strategy for hyperactive immunocompetent primary and immunocompromised secondary bacterial pneumonia.

Ni-Containing Electrolytes for Superior Zinc-Ion Aqueous Batteries with Zinc Hexacyanoferrate Cathodes

A one-step coprecipitation process is designed to synthesize zinc hexacyanoferrate (ZnHCF) cathodes in aqueous zinc-ion batteries (ZIBs). The morphology of the cathode is influenced by the concentration of the precursor solution and valence of iron ions. The rhombohedral ZnHCF sample exhibits high crystallinity on the microscale in the cut-angle cubic structure, whereas Na-rich NaZnHCF contains many interstitial water molecules in the rhombic nanoplates. Both samples show effective insertion of Zn ions in the aqueous ZnSO₄ solution. ZnHCF shows a specific capacity of 66.7 mA h g^-1, a redox voltage of 1.73 V, and fast decline in a few cycles. On the other hand, NaZnHCF has a lower specific capacity of 48.2 mA h g^-1, showing two voltage platforms and robust cycling stability. However, owing to serious side reactions, both samples have low Columbic efficiency. To improve the properties such as Coulombic efficiency, specific capacity, and cycling stability, Ni ions are introduced by adding 10 wt % NiSO₄ to the ZnSO₄ electrolyte. The ZnHCF cathode in the Ni-containing electrolyte has the best properties such as a high specific capacity of 71.2 mA h g^-1 at a current density of 100 mA g^-1, 93% retention of the Coulombic efficiency, and a good rate performance manifested by a reversible capacity of 58.2 mA h g^-1 at 1 A g^-1. The results reveal a strategy to improve the electrochemical properties of aqueous ZIBs by modifying the electrolytes.

Reversibly Migratable Fluorescent Probe for Precise and Dynamic Evaluation of Cell Mitochondrial Membrane Potentials

The mitochondrial membrane potential (MMP, ΔΨ_mito) provides the charge gradient required for mitochondrial functions and is a key indicator of cellular health. The changes in MMP are closely related to diseases and the monitoring of MMP is thus vital for pathological study and drug development. However, most of the current fluorescent probes for MMP rely solely on the cell fluorescence intensity and are thus restricted by poor photostability, rendering them not suitable for long-term dynamic monitoring of MMP. Herein, an MMP-responsive fluorescent probe pyrrolyl quinolinium (PQ) which is capable of reversible migration between mitochondria and nucleolus is developed and demonstrated for dynamic evaluation of MMP. The fluorescence of PQ translocates from mitochondria to nucleoli when MMP decreases due to the intrinsic RNA-specificity and more importantly, the translocation is reversible. The cytoplasm to nucleolus fluorescence intensity ratio is positively correlated with MMP so that this method avoids the negative influence of photostability and imaging parameters. Various situations of MMP can be monitored in real time even without controls. Additionally, long-term dynamic evaluation of MMP is demonstrated for HeLa cells using PQ in oxidative environment. This study is expected to give impetus to the development of mitochondria-related disease diagnosis and drug screening.

Highly sensitive dual-core photonic quasicrystal fiber methane sensor based on surface plasmon resonance

A highly sensitive dual-core photonic quasicrystal fiber methane sensor based on surface plasmon resonance is designed and analyzed. In this sensor, cryptophane E is doped with polysiloxane and Ag and used as the sensitive film and plasma medium, respectively, for sensitive detection of methane. The influence of the structural parameters on the sensor properties is analyzed by the finite element method. The optimized dual-quasi-D-shape structure has excellent methane-sensing properties such as maximum and average wavelength sensitivities of 14 and 10.98 nm/%, respectively, in the methane concentration range of 0%-3.5%. The sensitivity is better than that of similar sensors reported previously.

Enhanced Activities in Alkaline Hydrogen and Oxygen Evolution Reactions on MoS2 Electrocatalysts by In-Plane Sulfur Defects Coupled with Transition Metal Doping

2D transition metal disulfides (TMDs) are promising and cost-effective alternatives to noble-metal-based catalysts for hydrogen production. Activation of the inert basal plane of TMDs is crucial to improving the catalytic efficiency. Herein, introduction of in-plane sulfur vacancies (S_v ) and 3d transition metal dopants in concert activates the basal planes of MoS₂ (M-S_v -MoS₂ ) to achieve high activities in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Acetate introducing mild wet chemical etching removes surface S atoms facilitating subsequent cation exchange between the exposed Mo atoms and targeted metal ions in solution. Density-functional theory calculation demonstrates that the exposed 3d transition metal dopants in MoS₂ basal planes serve as multifunctional active centers, which not only reduce ΔG_H* but also accelerate water oxidation. As a result, the optimal Ni-S_v -MoS₂ and Co-S_v -MoS₂ electrocatalysts show excellent stability and alkaline HER and OER characteristics such as low overpotentials of 101 and 190 mV at 10 mA cm^-2 , respectively. The results reveal a strategy to activate the inert MoS₂ basal planes by defect and doping co-engineering and the technique can be extended to other types of TMDs for high-efficiency electrocatalysis beyond water splitting.

Phosphorus-Based Materials for High-Performance Alkaline Metal Ion Batteries: Progress and Prospect

Alkaline metal-ion batteries (AIBs) such as lithium-ion batteries (LIBs), sodium-ion batteries (NIBs), and potassium-ion batteries (KIBs) are potential energy storage systems. Currently, although LIBs are widely used in consumer electronics and electric vehicles, the electrochemical performance, safety, and cost of current AIBs are still unable to meet the needs for many future applications, such as large-scale energy storage, due to the low theoretical capacity of cathode/anode materials, flammability of electrolytes and limited Li resources. It is thus imperative to develop new materials to improve the properties of AIBs. Several promising cathodes, anodes, and electrolytes have been developed and among the new battery materials, phosphorus-based (P-based) materials have shown great promise. For example, P and metal phosphide anodes have high theoretical capacity, resource abundance, and environmental friendliness boding well for future high-energy-density AIBs. Besides, phosphate cathode materials have the advantages of low cost, high safety, high voltage, and robust stability, and P-based materials like LiPF₆ and lithium phosphorus oxynitride are widely used electrolytes. In this paper, the latest development of P-based materials in AIBs, challenges, effective solutions, and new directions are discussed.

Fabricating Black-Phosphorus/Iron-Tetraphosphide Heterostructure via a Solid-Phase Solution-Precipitation Method for High-Performance Nitrogen Reduction

Although constructing heterostructures is considered as one of the most successful strategies to improve the activity of a catalyst, the heterostructures usually suffer from the cumbersome preparation treatments and low-yield. Inspired by a solid-phase solution-precipitation (SPSP) process, an approach for interface intensive heterostructures with high yield is developed. Herein, a black-phosphorus/iron-tetraphosphide (BP/FeP₄ ) heterostructure is prepared mechanochemically with high transient pressure by the solid-phase ball milling approach. The BP/FeP₄ heterostructure delivers excellent catalytic performance in the nitrogen reduction reaction (NRR) as exemplified by an NH₃ yield of 77.6 µg h^-1 mg cat . - 1 \[{\rm{mg}}_{{\rm{cat}}{\rm{.}}}^{{\bm{ - }}1}\] and Faradic efficiency of 62.9% (-0.2 V), which are superior to that of most NRR catalysts recently reported. Experimental investigation and density-functional theory calculation indicate the importance of excess phosphorus in the heterostructures on the NRR activity, which assists the Fe atom to activate N₂ via adsorbing the H atom. The results demonstrate the great potential of this new type of heterostructures prepared by the SPSP approach. Benefiting from the simple preparation process and low cost, the heterostructures offer a new insight into the development of highly efficient catalysts.

Modulation of Redox Chemistry of Na2Mn3O7 by Selective Boron Doping Prompted by Na Vacancies

The small energy density and chemomechanical degradation of layered manganese oxide limit practical application to sodium-ion batteries (SIBs). Typically, Na₂Mn₃O₇ shows a low redox plateau at 2.1 V versus Na/Na⁺, and the oxygen redox reaction at a high voltage causes structural collapse. Herein, a Na vacancy-induced boron doping strategy is demonstrated to improve the properties. Boron is incorporated into selective sites in the lattice in the center of the MnO₆ octahedral ring at the O-layer. Bonding of boron in the TM layer enhances the electrochemical activity of low-valence Mn, giving rise to two reversible redox peaks at 2.45 and 2.55 V to enhance the average redox voltage. At the same time, the O 2p chemical state becomes weaker around the Fermi level, thus suppressing oxygen overoxidation for the high charge state and strengthening the layered structure during the redox reactions. The reduced Mn-O covalency and small diffusion barrier energy stemming from bonding of boron in the oxygen layer produce excellent rate characteristics. Modulation of the Mn 3d and O 2p orbital in Na₂Mn₃O₇ by Na vacancies leads to selective doping of boron at different sites, and our results reveal that it is an important strategy for studying transition-metal-oxide-layered electrode materials.

In situ growth of Ca-Zn-P coatings on the Zn-pretreated WE43 Mg alloy to mitigate corrosion and enhance cytocompatibility

Magnesium (Mg) alloys are potential materials for orthopedic fixation devices but rapid degradation of the materials restricts wider clinical applications. Herein, zinc-incorporated calcium phosphate (Ca-Zn-P) coatings are prepared on the Zn-pretreated WE43 Mg alloy by a hydrothermal technique under relatively stable and favorable conditions. The hydrothermal coating consists of a compact bottom layer of CaZn₂(PO₄)₂∙2 H₂O and ZnO granular crystals and a jagged upper layer of CaHPO₄. The Zn coating reduces the corrosion current density of WE43 to (3.49 ± 1.60) × 10^-5 A cm^-2, whereas the Ca-Zn-P/Zn composite coating further reduces it by 3 orders of magnitude in the simulated body fluid (SBF). The charge transfer resistances of the Zn-coated and Ca-Zn-P/Zn-coated alloys increase by 49 and 7176 times to 835 and 1.22 × 10⁵ Ω cm², respectively. The 7-day immersion results reveal that the Zn coating cannot provide long-term protection to WE43 in SBF because of the formation of galvanic couples between the Zn coating and WE43. In contrast, Ca-Zn-P/Zn-coated WE43 remains intact after soaking for 7 days and furthermore, the Ca-Zn-P coating self-repairs and continues to grow despite dissolution. The compact and adherent Ca-Zn-P bottom layer plays a major role in mitigating corrosion of WE43 by hindering penetration of the aggressive medium and charge transfer of the corrosion reactions resulting in only slight corrosion of the Zn layer. Biologically, the Zn coating reduces attachment and proliferation of MC3T3-E1 pre-osteoblasts on WE43, but the composite coating fosters cell adhesion and proliferation which stems from the good biocompatibility of the hydrothermal layer and relatively stable surface conditions avoiding severe corrosion.

Electric field enhancement by a hybrid dielectric-metal nanoantenna with a toroidal dipole contribution

Plasmonic nanocavities enable extreme light-matter interactions by pushing light down to the nanoscale. The numerical simulation is carried out systematically on the slotted Φ-shaped Si disk system with the super-dipole mode based on the analysis of the scattering strength of electric and toroidal dipoles. New blocks are introduced to the zero-field strength region of a slotted Si disk system as a function of the field enhancement factors. The far-field scattering characteristics and near-field electromagnetic field distributions are investigated by a multipole decomposition analysis to elucidate the intrinsic causes of the field enhancement. In the hybrid metal-dielectric nanoantenna, the Φ-shaped Si structure is prepared by superimposing Au nanoantennas for further field enhancement. In addition, the effects of the placement of an electric dipole emitter on the Purcell factor are derived. The geometric volume of the system is increased, and the electric field strength is improved, leading to an electric field increase of ∼30. Coupling between the super-dipole mode of the dielectric nanostructure and plasmonic modes of the metallic nanoantenna produces an enhancement as large as 16 times. Our results reveal a greatly enhanced super-dipole mode by electromagnetic coupling in composite structures, which will play a significant role in enhanced nonlinear photonics, near-field enhancement spectroscopy, and strong photon-exciton coupling.

Ti3 C2 TX MXene Modified with ZnTCPP with Bacteria Capturing Capability and Enhanced Visible Light Photocatalytic Antibacterial Activity

Light-assisted antibacterial therapy is a promising alternative to antibiotic therapy due to the high antibacterial efficacy without bacterial resistance. Recent research has mainly focused on the use of near-infrared light irradiation to kill bacteria by taking advantage of the synergistic effects rendered by hyperthermia and radical oxygen species. However, photocatalytic antibacterial therapy excited by visible light is more convenient and practical, especially for wounds. Herein, a visible light responsive organic-inorganic hybrid of ZnTCPP/Ti₃ C₂ T_X is designed and fabricated to treat bacterial infection with antibacterial efficiency of 99.86% and 99.92% within 10 min against Staphylococcus aureus and Escherichia coli, respectively. The porphyrin-metal complex, ZnTCPP, is assembled on the surface of Ti₃ C₂ T_X MXene to capture bacteria electrostatically and the Schottky junction formed between Ti₃ C₂ T_X and ZnTCPP promotes visible light utilization, accelerates charge separation, and enhances the mobility of photogenerated charges, and finally increases the photocatalytic activity. As a result of the excellent bacteria capturing ability and photocatalytic antibacterial effects, ZnTCPP/Ti₃ C₂ T_X exposed to visible light has excellent antibacterial properties in vitro and in vivo. Therefore, organic-inorganic materials that have been demonstrated to possess good biocompatibility and enhance wound healing have large potential in bio-photocatalysis, antibacterial therapy, as well as antibiotics-free treatment of wounds.

Highly Durable and Efficient Ni-FeOx/FeNi3 Electrocatalysts Synthesized by a Facile In Situ Combustion-Based Method for Overall Water Splitting with Large Current Densities

Ni-/Fe-based materials are promising electrocatalysts for the oxygen evolution reaction (OER) but usually are not suitable for the hydrogen evolution reaction (HER). Herein, a durable and bifunctional catalyst consisting of Ni-FeO_x and FeNi₃ is prepared on nickel foam (Ni-FeO_x/FeNi₃/NF) by in situ solution combustion and subsequent calcination to accomplish efficient alkaline water splitting. Density functional theory (DFT) calculation shows that the high HER activity is attributed to the strong electronic coupling effects between FeO_x and FeNi₃ in the Janus nanoparticles by modulating ΔG_H* and electronic states. Consequently, small overpotentials (η) of 71 and 272 mV in HER and 269 and 405 mV in OER yield current densities (j) of 50 and 1000 mA cm^-2, respectively. The catalyst shows outstanding stability for 280 and 200 h in HER and OER at a j of ∼50 mA cm^-2. Also, the robustness and mechanical stability of the electrode at an elevated j of ∼500 mA cm^-2 are excellent. Moreover, Ni-FeO_x/FeNi₃/NF shows excellent water splitting activities as a bifunctional catalyst as exemplified by j of 50 and 500 mA cm^-2 at cell voltages of 1.58 and 1.80 V, respectively. The Ni-FeO_x/FeNi₃/NF structure synthesized by the novel, simple, and scalable strategy has large potential in commercial water electrolysis, and the in situ combustion method holds great promise in the fabrication of thin-film electrodes for different applications.

Construction of α-MnO2 on Carbon Fibers Modified with Carbon Nanotubes for Ultrafast Flexible Supercapacitors in Ionic Liquid Electrolytes with Wide Voltage Windows

In this study, α-MnO₂ and Fe₂O₃ nanomaterials are prepared on a carbon fiber modified with carbon nanotubes to produce the nonbinder core–shell positive (α-MnO₂@CNTs/CC) and negative (Fe₂O₃@CNTs/CC) electrodes that can be operated in a wide voltage window in ultrafast asymmetrical flexible supercapacitors. MnO₂ and Fe₂O₃ have attracted wide research interests as electrode materials in energy storage applications because of the abundant natural resources, high theoretical specific capacities, environmental friendliness, and low cost. The electrochemical performance of each electrode is assessed in 1 M Na₂SO₄ and the energy storage properties of the supercapacitors consisting of the two composite electrodes are determined in Na₂SO₄ and EMImBF4 electrolytes in the 2 V and 4 V windows. The 2 V supercapacitor can withstand a large scanning rate of 5000 mV S⁻¹ without obvious changes in the cyclic voltammetry (CV) curves, besides showing a maximum energy density of 57.29 Wh kg⁻¹ at a power density of 833.35 W kg⁻¹. Furthermore, the supercapacitor retains 87.06% of the capacity after 20,000 galvanostatic charging and discharging (GCD) cycles. The 4 V flexible supercapacitor shows a discharging time of 1260 s and specific capacitance of 124.8 F g⁻¹ at a current of 0.5 mA and retains 87.77% of the initial specific capacitance after 5000 GCD cycles. The mechanical robustness and practicality are demonstrated by physical bending and the powering of LED arrays. In addition, the contributions of the active materials to the capacitive properties and the underlying mechanisms are explored and discussed

Detection of kerosene adulteration in automobile fuel by a low-loss surface plasmon resonance (SPR) chemical sensor

A surface plasmon resonance (SPR) chemical sensor with gold as the sensitive material has been designed to detect the adulteration of petrol by kerosene. Samples of petrol adulterated with kerosene were prepared in different ratios by volume (v/v). Kerosene concentrations ranging from 0% to 80% can be detected by monitoring the optical spectra, and the properties of the sensor were analyzed using the COMSOL Multiphysics software. The sensor shows a high spectral sensitivity of 7117 nm per RIU and a sensing resolution of 1.4 × 10^-4 RIU. The excellent sensing properties and a low confinement loss of 5.4 dB cm^-1 render the sensor competitive in SPR sensing applications.

In-Plane Mott-Schottky Effects Enabling Efficient Hydrogen Evolution from Mo5 N6 -MoS2 Heterojunction Nanosheets in Universal-pH Electrolytes

Cost-effective electrocatalysts for the hydrogen evolution reaction (HER) spanning a wide pH range are highly desirable but still challenging for hydrogen production via electrochemical water splitting. Herein, Mo₅ N₆ -MoS₂ heterojunction nanosheets prepared on hollow carbon nanoribbons (Mo₅ N₆ -MoS₂ /HCNRs) are designed as Mott-Schottky electrocatalysts for efficient pH-universal HER. The in-plane Mo₅ N₆ -MoS₂ Mott-Schottky heterointerface induces electron redistribution and a built-in electric field, which effectively activates the inert MoS₂ basal planes to intrinsically increase the electrocatalytic activity, improve electronic conductivity, and boost water dissociation activity. Moreover, the vertical Mo₅ N₆ -MoS₂ nanosheets provide more activated sites for the electrochemical reaction and facilitate mass/electrolyte transport, while the tightly coupled HCNRs substrate and metallic Mo₅ N₆ provide fast electron transfer paths. Consequently, the Mo₅ N₆ -MoS₂ /HCNRs electrocatalyst delivers excellent pH-universal HER performances exemplified by ultralow overpotentials of 57, 59, and 53 mV at a current density of 10 mA cm^-2 in acidic, neutral, and alkaline electrolytes with Tafel slopes of 38.4, 43.5, and 37.9 mV dec^-1 , respectively, which are superior to those of the reported MoS₂ -based catalysts and outperform Pt in overall water splitting. This work proposes a new strategy to construct an in-plane heterointerface on the nanoscale and provides fresh insights into the HER electrocatalytic mechanism of MoS₂ -based heterostructures.

Atomistic Observation of the Local Phase Transition in MoTe2 for Application in Homojunction Photodetectors

Direct atomic-scale observation of the local phase transition in transition metal dichalcogenides (TMDCs) is critically required to carry out in-depth studies of their atomic structures and electronic features. However, the structural aspects including crystal symmetries tend to be unclear and unintuitive in real-time monitoring of the phase transition process. Herein, by using in situ transmission electron microscopy, information about the phase transition mechanism of MoTe₂ from hexagonal structure (2H phase) to monoclinic structure (1T' phase) driven by sublimation of Te atoms after a spike annealing is obtained directly. Furthermore, with the control of Te atom sublimation by modulating the hexagonal boron nitride (h-BN) coverage in the desired area, the lateral 1T'-enriched MoTe₂ /2H MoTe₂ homojunction can be one-step constructed via an annealing treatment. Owing to the gradient bandgap provided by 1T'-enriched MoTe₂ and 2H MoTe₂ , the photodetector composed of the 1T'-enriched MoTe₂ /2H MoTe₂ homojunction shows fast photoresponse and ten times larger photocurrents than that consisting of a pure 2H MoTe₂ channel. The study reveals a route to improve the performance of optoelectronic and electronic devices based on TMDCs with both semiconducting and semimetallic phases.

Anti-tumor immunity and ferroptosis of hepatocellular carcinoma are enhanced by combined therapy of sorafenib and delivering modified GO-based PD-L1 siRNAs

Programmed cell death receptor ligand 1 (PD-L1)/PD-1 signaling has been exploited to design inhibitors that deliver promising clinical outcome albeit with limited efficacy. Herein, we prepare graphene oxide (GO)-PEI-PEG with low cytotoxicity and long stability and GO-PEI-PEG delivers PD-L1 siRNAs to hepatocellular carcinoma (HCC) cells by the endocytosis-lysosome pathway. The functional GO-PEI-PEG/PD-L1 siRNAs decrease PD-L1 and PD-1 abundance, increase pro-inflammation cytokine IFN-γ and TNF-α release, and improve the proliferation activity of Jurkat T cells. Since GO-PEI-PEG targets the mouse liver effectively, the intrahepatic tumors in C57BL/6 mice are treated with GO-PEI-PEG/Pd-l1 siRNAs via the tail vein, resulting in shrinkage of the HCC tumors and boosting the anti-tumor efficacy in combination with oral sorafenib. A single treatment improves the total CD3⁺ and cytotoxic CD8⁺ T cell infiltration in the HCC tumor tissues and even spleen and upregulates the expression of Perforin, Gzmb, Ifng, Il-1b and Tnfa in the tumors after the combined treatment. Both the single and combined treatments enhance reactive oxygen species (ROS) accumulation, and improved HCC ferroptosis. The results suggest that GO-PEI-PEG delivered PD-L1 siRNAs combined with oral sorafenib can activate the adaptive immunity and tumor ferroptosis and reveal an effective therapy to treat advanced HCC patients.

Exosomes derived from magnesium ion-stimulated macrophages inhibit angiogenesis

Angiogenesis, an essential prerequisite to osteogenesis in bone repair and regeneration, can be mediated by immunoregulation of macrophages. Magnesium and its alloys are promising biodegradable bone implant materials and can affect immunoregulation of macrophages by the degradation products (magnesium ions. Nevertheless, the mechanism of macrophage-derived exosomes stimulated by Mg ions in immunoregulation is still not well understood. Herein, 10-50 mM magnesium ions are shown to inhibit the macrophage viability and proliferation in a dose-dependent manner, but a high concentration results in macrophage apoptosis. The exosomes secreted by macrophages from magnesium ion stimulation inhibit angiogenesis of endothelial cells, as manifested by the suppressed cell viability, proliferation, migration, and tube formation, which arise at least partially from exosome-mediated downregulation of endothelial nitric oxide and the vascular endothelial growth factor. The findings reported in this paper suggest that the bio-functionality of biodegradable magnesium alloys must be considered from the perspective of immunoregulation of macrophage-derived exosomes. Our results also suggest potential cancer therapy by inhibiting tumor-associated angiogenesis.

Hydrogels as Soft Ionic Conductors in Flexible and Wearable Triboelectric Nanogenerators

Flexible triboelectric nanogenerators (TENGs) have attracted increasing interest since their advent in 2012. In comparison with other flexible electrodes, hydrogels possess transparency, stretchability, biocompatibility, and tunable ionic conductivity, which together provide great potential as current collectors in TENGs for wearable applications. The development of hydrogel-based TENGs (H-TENGs) is currently a burgeoning field but research efforts have lagged behind those of other common flexible TENGs. In order to spur research and development of this important area, a comprehensive review that summarizes recent advances and challenges of H-TENGs will be very useful to researchers and engineers in this emerging field. Herein, the advantages and types of hydrogels as soft ionic conductors in TENGs are presented, followed by detailed descriptions of the advanced functions, enhanced output performance, as well as flexible and wearable applications of H-TENGs. Finally, the challenges and prospects of H-TENGs are discussed.