Nanotechnology最新文献

Retinal detachment (RD) is a common acute blinding eye disease, and dexamethasone (DEX), an adrenocorticosteroid, shows protective effects against RD. However, its poor water solubility and low bioavailability limit its effectiveness. To address this, we developed SF@DEX nanomaterials and investigated their therapeutic potential and mechanisms in RD. The nanomaterials were successfully synthesized and characterized, achieving 90% encapsulation efficiency and releasing 60% of DEX within 12 h.In vitro, phagocytosis was measured by flow cytometry, and enzyme-linked immunosorbent assay determined interleukin-17 (IL-17) and interleukin-10 (IL-10) levels. A rat RD model was established surgically, followed by oral administration of silk fibroin (SF), SF@DEX, and DEX. Polymerase chain reaction (PCR) assessed IL-17A and forkhead box P3 (FOXP3) expression, while Western blot analysed transforming growth factor-β1 (TGF-β1), IL-10, IL-17A, and FOXP3 levels. Apoptosis of retinal ganglion cells was evaluated using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and confocal microscopy detected colocalization of IL-17A and FOXP3. SF@DEX treatment significantly reduced Th17 cells and IL-17A while increasing Tregs, FOXP3, TGF-β1, and IL-10 levels. The severity of RD in rats was notably alleviated by SF@DEX, demonstrating its anti-inflammatory effects through modulation of the Th17/Treg immune balance. These results highlight SF@DEX as a promising nano-based therapy for RD.

Developing a reliable procedure for the growth of III-V nanowires (NW) on silicon (Si) substrates remains a significant challenge, as current methods rely on trial-and-error approaches with varying interpretations of critical process steps such as sample preparation, Au-Si alloy formation in the growth reactor, and nanowire alignment. Addressing these challenges is essential for enabling high-performance electronic and optoelectronic devices that combine the superior properties of III-V NW semiconductors with the well-established Si-based technology. Combining conventional scalable growth methods, such as Metalorganic Chemical Vapor Deposition (MOCVD) with in situ characterization using Environmental Transmission Electron Microscopy (ETEM-MOCVD) enables a deeper understanding of the growth dynamics, if that knowledge is transferable to the scalable processes. We report on successful epitaxial growth of Au-catalyzed GaAs NWs on Si(111) substrates using micro-electromechanical system (MEMS) chips with monocrystalline Si-cantilevers in both conventional MOCVD and ETEM-MOCVD systems. The conventional MOCVD provided a framework for initial parameter tuning, while ETEM-MOCVD offered valuable insights into early nucleation and catalyst-substrate interactions. Our findings show that nucleation is significantly influenced by the removal of native oxide layers and the initial formation of the Au-Si alloy. Our in situ studies revealed different NW-substrate interfaces, essential for optimizing the epitaxial growth process. We identified three typical configurations of NW "roots", each impacted by growth conditions and preparation steps, affecting the structural and potentially the optical properties of the NWs. Similarly, doping from the Si-substrate may affect both optical and electrical properties; however, compositional analysis revealed no traces of Si in NWs post-nucleation and a small amount in the catalytic droplet. Our research highlights the importance of in situ studies for a comprehensive understanding of nucleation mechanisms, paving the way for optimizing III-V NW growth on Si substrates and developing high-performance III-V/Si devices.

InSb is a material of choice for infrared as well as spintronic devices but its integration on large lattice mismatched semi-insulating III-V substrates has so far altered its exceptional properties. Here, we investigate the direct growth of InSb on InP(111)_Bsubstrates with molecular beam epitaxy. Despite the lack of a thick metamorphic buffer layer for accommodation, we show that quasi-continuous thin films can be grown using a very high Sb/In flux ratio. The quality of the films is further studied with Hall measurements on large-scale devices to assess the impact of the InSb surface and InSb/InP interface on the electronic properties. Taking advantage of the optimized growth conditions for the formation of thin films, the selective area molecular beam epitaxial growth of nanostructures is subsequently investigated. Based on cross-sectional transmission electron microscopy and scanning near-field optical microscopy in the middle-wave infrared, ultra-thin and very long in-plane InSb nanowires as well as more complex nanostructures such as nano-rings and crosses are achieved with a good structural quality.

Lead-free cesium bismuth iodide (Cs₃Bi₂I₉) perovskite exhibits extraordinary optoelectronic properties and attractive potential in various optoelectronic devices, especially the application for photodetectors. However, most Cs₃Bi₂I₉photodetectors demonstrated poor detection performance due to the difficulty in obtaining high-quality polycrystalline films. Therefore, it makes sense to modulate the preparation of high-quality Cs₃Bi₂I₉polycrystalline films and expand its applications. Here, a solvent-modulated method combining anti-solvent and precursor engineering has been developed to regulate the crystallization dynamics of Cs₃Bi₂I₉. Anti-solvent treatment is to suppress the asynchronous separation out of CsI and BiI₃due to significant differences in solubility, promoting uniform nucleation and limiting flake-like growth. Precursor engineering is synchronously used to modulate the subsequent nucleation growth dynamics. Due to the synergistic modulation, smooth and compact Cs₃Bi₂I₉polycrystalline films with distinct grains and grain boundaries can be easily obtained. The as-prepared photodetector exhibits an excellent on/off ratio of 4.26×10⁵as well as the detectivity up to 6.49×10¹⁰Jones at zero bias. And, the Cs₃Bi₂I₉photodetector indicates excellent device stability, maintaining about 70% of the original performance after being stored for 400 hours in the air without encapsulation. .

Strain sensing fabrics are able to sense the deformation of the outside world, bringing more accurate and real-time monitoring and feedback to users. However, due to the lack of clear sensing mechanism for high sensitivity and high linearity carbon matrix composites, the preparation of high performance strain sensing fabric weaving is still a major challenge. Here, an elastic polyurethane (PU)-based conductive fabric (GCPU) with high sensitivity, high linearity and good hydrophobicity is prepared by a novel synergistic conductive network strategy. The GCPU fabric consists of graphene sheets (GS)/carbon nanotubes (CNTs) elastic conductive layer and a PU elastic substrate. GS and CNTs can be constructed into a synergistic conductive network, and the fabric is endowed with high conductivity (1.193 S m^-1). Simulated equivalent circuits show that GS in the conductive network will break violently under applied strain, making the GCPU fabric extremely sensitive (gauge factor 102). CNTs are spatially distributed in GS lamellae, avoiding the phenomenon that the constructed synergistic conductive network is violently fractured under the applied strain, which leads to the decrease of linearity (0.996). Styrene-ethylene-butylene-styrene (SEBS) was used as a dispersant and binder to uniformly disperse and closely bond GS and CNTs into PU fabrics. In addition, the hydrophobicity of SEBS makes the GCPU fabric resistant to water environment (The contact angle is 123°). Due to the good mechanical stability of GCPU fabric, GCPU fabric has a wide strain range (0%-50%) and high cycle stability (over 1000 cycles). In practice, GCPU fabric can accurately simulate and detect the size and deformation motion of human body. Therefore, the successful construction of elastic fabrics with synergistic conductive networks provides a feasible path for the design and manufacture of wearable intelligent fabrics.

The utilization of dual-working-electrode mode of interdigitated array (IDA) electrodes and other two-electrode systems has revolutionized electrochemical detection by enabling the simultaneous and independent detection of two species, accompanied by the exhibition of unique characteristics. In contrast to conventional dual-potential electrodes, such as the rotating ring disk electrodes (RRDE), IDA electrodes demonstrate analogous yet vastly improved performance, characterized by remarkable collection efficiency and sensitivity. Notably, due to the distinctive microscale structure of IDA electrode, the special "feedback" effect makes IDA a unique signal amplifier. In recent decades, the research surrounding IDA electrodes has garnered escalating interest due to their attractive attributes. This review centers its focus on the fabrication and applications of IDA electrodes. In fabrication, two critical breakthroughs are poised for realization: the achievement of reduced dimensions and the diversification of materials. Established fabrication methods for IDA electrodes encompass photolithography, inkjet printing, and direct laser writing, each affording distinct advantages in terms of size and precision in IDA construction. Predominantly employed materials for IDA electrodes include gold, platinum, and carbon, with the selection of fabrication methods guided by considerations such as material properties, desired dimensions, cost-efficiency, and specific application requisites. In terms of applications, IDA electrodes, capitalizing on their distinctive attributes, have found utility in diverse fields. This review summarizes the applications of IDA electrodes based on their fundamental working principles, encompassing redox cycling, resistance modulation, capacitance variations, and more. The potential for further development of this specialized tool to exhibit enhanced properties holds substantial promise. .

Graphitic carbon nitride (g-C3N4) has gained significant attention as a promising nonmetallic semiconductor photocatalyst due to its photochemical stability, favorable electronic properties, and efficient light absorption. Nevertheless, its practical applications are hindered by limitations such as low specific surface area, rapid recombination of photogenerated charge carriers, poor electrical conductivity, and restricted photo-response ranges. This review explores recent advancements in the synthesis, modification and application of g-C3N4 and its nanocomposites with a focus on addressing these challenges. Key strategies for enhancing g-C3N4 include various synthesis methods (solvothermal, microwave-assisted, sol-gel, and vapor deposition), doping, defect engineering, heterojunction formation, and surface modifications. Their potential in energy storage and conversion applications, including photocatalytic hydrogen production, carbon dioxide reduction, nitrogen fixation, and electrochemical energy storage are also highlighted. Overall, the review underscores the importance of structural and morphological modifications in improving the photoelectrochemical performance of g-C3N4-based nanocomposites, providing insights for future development and optimization.

Although Mg-Li dual metal-ion batteries are proposed as a superior system that unite safety of Mg-batteries and performance of Li-ion based systems, its practical implantation is limited due to the lack of reliable high-performance cathodes. Herein, we report a high-performance Mg-Li dual metal-ion battery system based on highly pseudocapacitive hierarchical TiO₂-B nanosheet assembled spheres (NS) cathode. This 2D cathode displayed exceptional pseudocapacitance (a maximum of 93%) specific capacity (303 mAh g^-1at 25 mA g^-1), rate performance (210 mAh g^-1at 1 A g^-1), consistent cycling (retain ∼100% capacity for 3000 cycles at 1 A g^-1), Coulombic efficiency (nearly 100%) and fast-charging (∼12.1 min). These properties are remarkably dominant to the existing Mg-Li dual metal-ion battery cathodes. Spectroscopic and microscopic mechanistic studies confirmed negligible structural changes during charge-discharge cycles of the TiO₂-B nanosheet assembled spheres electrodes. Exceptional electrochemical properties of the 2D electrode is ascribed to remarkable pseudocapacitive Mg-Li dual metal-ion diffusion via the numerous nanointerfaces of TiO₂-B caused by its hierarchical microstrucrure. Large surface area, nanosheet morphology, mesoporous structure and ultrathin nature also acted as secondary factors facilitating improved electrode-electrolyte contact. Demonstrated approach of pseudocapacitive type Mg-Li dual metal-ion intercalation through hierarchical nanointerfaces may be further utilized for the designing of numerous top-notch electrode materials for futuristic Mg-Li dual metal-ion batteries.

In the post-lithium-ion battery era, potassium-ion batteries (PIBs) have been considered as a promising candidate because of their electrochemical and economic characteristics. However, as an emerging electrochemical storage technology, it is urgent to develop capable anode materials that can be produced at low cost and on a large scale to promote its practical application. Biomass-derived carbon materials as anodes of PIBs exhibit strong competitiveness by their merits of low weight, high stability, non-toxicity, and wide availability. In this work, we employed Platanus occidentalis L. fruits as a precursor to prepare a series of biomass-derived carbon materials by simply adjusting carbonization temperature, and we explored their electrochemical potassium storage capability as anode materials. The optimized sample (annealed at 800 °C) delivered good potassium storage capability (193.3 mAh g^-1at 100 mA g^-1after 100 cycles), cycling stability (80.4 mAh g^-1after 300 cycles at 300 mA g^-1), and rate performance (51.2 mAh g^-1at 1000 mA g^-1). This work demonstrates a feasible way to utilize biomass waste disposal for emerging sustainable energy storage technologies.

This study investigates the enhancement of damping properties in carbon fiber-reinforced polymer (CFRP) composites by incorporating graphene nanoplatelets (GNPs) into the epoxy matrix. Epoxy and CFRP specimens with varying GNP concentrations, were developed and tested through free vibration experiments to measure damping ratios. Additionally, a computational model based on the finite element method was developed to simulate the damping behavior of these hybrid nanocomposites. Using periodic representative volume elements under sinusoidal axial loads, the model accurately predicted damping performance by calculating the time lag between applied loads and resulting deformations. Comparison of numerical results with experimental data revealed a strong correlation, confirming the model's effectiveness in capturing the influence of GNP mass fraction on damping enhancement.