Journal of Science: Advanced Materials and Devices最新文献

In this study, we fabricated vertical Schottky barrier diodes (SBDs) based on wide bandgap semiconductor beta-phase gallium oxide (β-Ga₂O₃) and silicon carbide (SiC), respectively, and conducted proton irradiation experiments to analyze the radiation hardness of the SBDs comparatively. The effects of proton radiation on the performance of SBDs were assessed through measurements of forward current, capacitance, and breakdown characteristics. Both devices exhibited degradation in current and capacitance characteristics following proton irradiation, attributed to displacement damage (DD). Notably, the β-Ga₂O₃-based SBD demonstrated more pronounced deterioration compared to the SiC-based device despite similar vacancy distributions as confirmed by SRIM simulation. Moreover, a decrease in contact radius correlated with exacerbated degradation in the current characteristics of the β-Ga₂O₃-based SBD. Following proton irradiation, breakdown voltages of both devices increased due to elevated resistance induced by displacement damage. While both β-Ga₂O₃ and SiC-based SBDs experienced displacement damage under high fluence proton irradiation, the extent of performance degradation varied depending on the dimensions and quality of epitaxial and substrate layers.

The advancement of future electronic devices necessitates dielectric materials with enhanced compositional complexity and improved capabilities. We here demonstrate a gas-phase alloying approach that yields ultrathin and crystalline dielectrics with attractive properties for the integration into electronics. A surface-selective deposition process was shown to produce sulfur (S) and selenium (Se) alloys with large-scale uniformity. Through combination of experimental diffraction analysis and materials modeling, we establish the crystallinity of the alloy with a modified lattice structure compared to the host materials. The resulting lattice arrangement endows the alloy dielectric with high ionic mobility as validated by electrochemical impedance spectroscopy. Leveraging this innovative feature, we fabricate memristive devices exhibiting promising performance characteristics. Our findings demonstrate the feasibility of utilizing gas-phase alloying to engineer dielectrics with superior properties and functionality for future device integration.

We successfully synthesized three-layered photocatalysts by modifying Bi nanoparticles on TiO₂/BiVO₄ bilayer composite films through a sol-gel process and sputtering. When exposed to ambient air, the surface of the prepared Bi nanoparticles oxidizes to form an amorphous ultra-thin Bi₂O₃ out layer. Under light exposure, this layer is reduced to metallic Bi, thanks to the band alignment between the Bi nanoparticles and TiO₂/BiVO₄ Z-scheme composite. The addition of Bi nanoparticles in the composite films improves visible-light absorption by the surface plasmon resonance (SPR), which contributes to the hot electron and enhances the photocatalytic characteristics. By constructing effective TiO₂/BiVO₄ Z-scheme heterostructures to facilitate photoinduced electron-hole pair separation and prevent recombination, Bi nanoparticles can efficiently capture photons and enhance the photocatalytic efficiency of semiconductors through the SPR effect. Optimizing the content of Bi nanoparticles decorated on the TiO₂/BiVO₄ Z-scheme composite film is a promising approach for designing a highly efficient photocatalyst, as evidenced by the performance of photoelectrochemical properties and RhB photodegradation ability.

Carbon nanotubes (CNT) are promising electroconductive nano-scale materials for neuroregeneration. Herein, we report on a new electroconductive composite scaffold made of the polymer 1% oxidized polyvinyl alcohol (OxPVA) combined with functionalized water soluble multiwalled CNT (OxPVA + MWCNT-S) (diazotization reaction). Preliminarily, MWCNT-S were characterized to evaluate the reaction outcome, the degree of functionalization and the dispersibility in water. Thereafter, OxPVA + MWCNT-S nanocomposite membranes were fabricated and analyzed for physicochemical properties (Raman spectroscopy, thermal decomposition, calorimetric properties, electroconductivity), macroscopic appearance and ultrastructure, mechanical behavior, in vitro cytotoxicity and in vivo biocompatibility. In parallel, OxPVA + MWCNT-S membranes with a linear pattern were also developed and analyzed for interaction with SH-SY5Y cells. Compared to OxPVA, the presence of MWCNT-S (only 0.016 wt%) significantly increased polymer conductivity and imparted a certain porosity without altering mechanical behaviour, as corroborated by uniaxial tensile tests. Neither cytotoxicity nor local signs of inflammation were detected in vitro and after subcutaneous implantation (14 and 42 days), proving composite material biocompatibility. OxPVA + MWCNT-S nanocomposite revealed as promising for future electroconductive conduits free from toxic effects amenable to CNT agglomeration within the polymer. Ideally, nerve lesions with wide gaps, may be effectively supported by those “active” devices, overcoming limitations of the available ones. Despite preliminary data, the presence of a linear pattern confirmed to have a beneficial effect over the scaffold/cells interaction.

Recent urbanization and environmental problems urge for networks of sensors that can monitor air quality. Small, inexpensive, and smart sensors are one of the key components enabling the realization of such networks. Chemoresistive sensors are the ideal candidate, but they greatly lack selectivity, and for this reason, they are usually combined in arrays to create electronic noses, whose dimensions, however, make them not miniaturizable and cannot be integrated into portable devices. To overcome this inconvenience, we present a thermal electronic nose consisting of identical resistive sensors working at different temperatures so that the whole device is simple to make and tiny. The device contains two sensor arrays based on tin oxide nanowires decorated with Ag and Pt nanoparticles, respectively. The five sensors in each array are identical, but their response is differentiated by different temperatures locally generated by an on-chip integrated heater. This innovative approach allows the tiny array of five sensors together with the integrated heater to occupy only approximately 50 × 200 μm² and consume only 120 μW. The tiny and portable device can estimate the concentration of H₂ and NH₃ in a mixture with a root mean square error of 6.1 ppm and 13.3 ppm, respectively, and it still works well after two months. The performance analysis of the double partial least squares regression used for concentration estimation also allows for feedback on which sensors are the most sensitive to which gas so that the electronic nose can be engineered for specific applications using the most suitable sensors. The size of the thermal electronic nose allows it to be integrated into portable and wearable devices, and its performance makes it suitable for any gas detection application. For example, a smartphone with an integrated sensor could carry out breath analysis and act as medical pre-screening or be used to evaluate the freshness of agri-food products in a rapid and non-invasive way.

The annual prevalence of gastric cancer has increased in recent years. Curcumin (CUR) has shown great potential in the treatment of gastric cancer; however, its low bioavailability and poor efficacy hinder its widespread clinical application. Additionally, CUR has been found to be excellent photosensitizer in photodynamic therapy. In this study, the Fe-based metal-organic framework (MOF) Fe Tetrakis (4-carboxyphenyl) porphyrin (Fe-TCPP，FT) was used as a photosensitizer and mononuclear agent. The natural anti-tumor active ingredient CUR was loaded as both a chemotherapeutic agent and photosensitizer to form the nanoparticles CUR@FT (CF). Finally, a cell-penetrating peptide (CPP10) was modified on the surface of the nanoparticles to construct a drug delivery system (named CPP10-PEG@CUR@FT, CCF) that could actively target tumor cells while exerting a synergistic therapeutic effect of chemotherapy and photodynamic therapy. This can improve the efficacy of CUR as a chemotherapeutic drug or photosensitizer, and the high drug load and pH sensitivity of FT nanoparticles provide an excellent carrier for the efficient delivery of CUR. The polyethene glycol (PEG)-conjugated CPP10 (PEG-CPP10) coating allows nanoparticles to specifically target gastric cancer cells, significantly improving the absorption of nanoparticles in vivo and in vitro and improving biosafety. We evaluated the thermal stability, drug loading capacity, and safety of FT as a drug delivery vehicle. We also assessed the in vitro photodynamic performance and toxicity of various nanoparticles and the targeting and biocompatibility of CPP10-PEG@CUR@FT. CPP10-PEG@CUR@FT could specifically target tumor cells, and its effect on killing gastric cancer cells (MKN45) under light was much stronger than that of free CUR. Its toxicity and side effects to other organs and tissues are low, offering good biosafety. The experimental results showed that FT and CUR exerted synergistic effects on photodynamic therapy and chemotherapy. In summary, our novel CUR-loaded targeted nano drug delivery system offers significant advantages by combining photodynamic therapy and chemotherapy for tumor treatment. This approach introduces a new concept for integrating chemotherapy, photodynamic therapy and targeted drug delivery, potentially providing a new strategy for the clinical treatment of gastric cancer.

The current investigation aims to study the bio route preparation of chitosan capped-silver nanoparticles using aqueous flower extract of the Achillea ptarmica plant. The biosynthesized silver nanoparticles/chitosan (Ag NPs@CHI) were characterized by various spectroscopic techniques. The creation of Ag nanoparticles over the chitosan was initially determined by the presence of a single broad peak at 545 nm that was recorded by the UV–Vis spectrum. The presence of poly-dispersity, spherical shape and nanosizes in the Ag NPs@CHI were verified by the TEM and SEM pictures. The purity and crystalline nature of the prepared Ag NPs@CHI were confirmed by XRD analysis. In vivo, Ag NPs@CHI decreased the inflammatory cells presence in the colon and ileum, lowered the levels of IL-17A, IL-1β, IL-6, and TNF-α, raised the levels of IL-10 and IL-4 in colon tissues, enhanced acetate and propionate production. The findings revealed that Ag NPs@CHI have the potential to boost intestinal structure restoration, decrease levels of inflammatory cytokines and enhance short-chain fatty acid (SCFA) levels. Our research demonstrated that Ag NPs@CHI can safeguard the intestinal barrier by upregulating the expression of Claudin-1 and Occludin. Furthermore, silver nanoparticles suppressed the MAPK signaling pathway to ameliorate the inflammatory condition. Following the completion of clinical trials, these novel nanoparticles could serve as a promising new treatment for diarrhea in humans.

In this work, graphene oxide (GO) was prepared via the Hummers’ method, whereas SrFe₁₂O₁₉, SrFe₁₂O₁₉@Fe₃O₄, and SrFe₁₂O₁₉@Fe₃O₄@rGO were fabricated using the hydrothermal techniques. The samples' phase structure, surface morphology, magnetic properties, and electromagnetic wave absorption characteristics were studied and compared. Findings show that the Fe₃O₄ particles adhered to the surface of the SrFe₁₂O₁₉ hexagonal plates, and the combination of SrFe₁₂O₁₉@Fe₃O₄ foam flakes and two-dimensional graphene rGO could enhance the absorption electromagnetic wave performance. The composite SrFe₁₂O₁₉@Fe₃O₄@rGO sample exhibited an ideal impedance matching within the frequency f range of 11 GHz–12.4 GHz. The minimum reflection loss reached −62.3 dB at 12.2 GHz with a thickness of 2 mm. With a thickness of 2 mm, the effective absorption bandwidth obtained the value of −20 dB, covering a range of 9.3 GHz. The composite SrFe₁₂O₁₉@Fe₃O₄@rGO sample, which shows the highest performance both in reflectivity and bandwidth, can find potential application in microwave absorptions.

The impact of the nanoparticles on the dyspepsia mice gut microbiota is evaluated through the utilization of the 16S rRNA technique. Various methods were employed to characterize the NPs. In the textile, culinary, paper, leather, and printing sectors, synthetic dyes are frequently employed as coloring agents. Because these dye molecules are harmful to both the environment and living things, it is difficult to remove them sustainably. Here, we have produced nanoparticles embedded in chitosan-polyvinyl alcohol hydrogel (CS-PVA) by using bark's Pistacia under ultrasonic irradiation. The reduction of Ag ⁺ ions into Ag⁰ NPs was detected by a visual change in the colors. UV–Vis analysis indicated that the characteristic SPR band appeared near ∼440–450 nm. UV/Vis, EDX-elemental mapping, SEM, TEM, ICP-OES, and XRD analysis were applied to characterize the Ag NPs/CS-PVA nanocomposite. The recent study focused on the cellular and molecular aspects. The MTT assay was conducted for 48 h to evaluate the anti-human gastric cancer and cytotoxicity efficacies of the treated cells with nanocomposite. The assessment was performed on normal (HUVEC) and gastric cancer cells, namely MKN45 and NCI–N87. The IC₅₀ values of nanocomposite against MKN45 and NCI–N87 were 180 and 151 μg/mL, respectively. The dose-dependent reduction in malignant gastric cell viability was observed in the nanocomposite presence. Furthermore, the nanocomposite induced cell apoptosis by 40–50%, leading to an increase in the expression of pro-apoptotic markers (Bax and cleaved caspase-8) and a decrease in the expression of the anti-apoptotic marker, Bcl-2. Furthermore, the nanocomposite showed inhibitory effects on colony formation. Our results indicate that the nanocomposite can increase p53 expression and decrease the expression of STAT3 in treated cells. This indicates that p53 and STAT3 play crucial roles in the biological effects induced by the extract in human gastric carcinoma cells. The data from the gut microbiome suggested that nanocomposites have the ability to control the rebalancing of homeostasis and microbiome composition by decreasing the levels of harmful bacteria, and at the same time, increasing the levels of beneficial bacteria. Following the introduction of nanocomposite, there was an observed rise in the levels of gastrointestinal hormones in the serum, including gastrin and motilin, while the levels of vasoactive intestinal peptide decreased. The application of nanocomposite led to an improvement in gastrointestinal movement, encompassing a rise in the rate of transit through the small intestine and the rate of gastric emptying. These findings offer that the Ag NPs/CS-PVA nanocomposite could be a promising anticancer treatment for functional dyspepsia and gastric cancer.

Dimethylaluminum isopropoxide (DMAI) is attracting attention as an alternative precursor for atomic layer deposition (ALD) of aluminum oxide (Al₂O₃). However, the surface chemical reaction mechanisms of DMAI during ALD regarding its dimeric structure under vacuum deposition process conditions has yet to be clear. In this work, the adsorption mechanism of dimeric and monomeric DMAI on a fully hydroxylated Al₂O₃ surface is studied using machine-learning potential (MLP) calculations. The initial adsorption of DMAI appears facile and would result in the coexistence of both methyl and isopropoxy ligands on the surface. The reactivity of DMAI is smaller than that of TMA, owing to the propensity of DMAI to adopt a dimeric form. Especially when the substrate is partially covered by other adsorbate species, the large molecular size and low reactivity of dimeric DMAI considerably hinder its reactivity toward surface adsorption. Current results are in good correspondence with the previous experimental results, where lower growth per cycle (GPC) and higher selectivity in area-selective ALD (AS-ALD) could be observed by using DMAI than compared to those of TMA processes.