Nanomaterials最新文献

Hyaluronic acid (HA)-based hydrogels offer a promising approach for soft tissue application due to their biocompatibility, tunable mechanical properties, ability to mimic the extracellular matrix, and capacity to support cell adhesion and proliferation. In this work, bioadhesive composite hydrogels were developed by integrating graphite derivatives (EG) into a dopamine-modified HA matrix (HA-Cat), which enhances tissue adhesion through catechol groups that mimic mussel-inspired adhesion mechanisms. The EG was functionalized via 1,3-dipolar cycloaddition reaction (f-EG), that allowed the anchoring of silver nanoparticles (f-EG-Ag) and grafting of hydrocaffeic acid (f-EG-Cat) on the functionalized EG surfaces. The hydrogels were produced by oxidative crosslinking of HA-Cat under mild basic pH conditions using sodium periodate. Indirect in vitro assays using L929 fibroblast cells showed high biocompatibility and enhanced cell proliferation at optimized composite hydrogel concentrations. These findings suggest that composite hydrogels could find an application as bioactive, adhesive scaffolds for the regeneration of soft tissues, where they can facilitate localized agent delivery and integration with the host tissue.

Electrochemical glucose sensors are vital for clinical diagnostics and the food industry, where accurate detection is essential. However, the limitations of glucose oxidase (GOx)-based sensors, such as complex preparation, high cost, and environmental sensitivity, highlight the need for non-enzymatic sensors that directly oxidize glucose at the electrode surface. In this study, a self-supporting hierarchical Cu/Fe₃O₄ nanosheet electrode was successfully fabricated by in situ growth on Ni Foam using a hydrothermal method, followed by annealing treatment. The Cu/Fe₃O₄ hierarchical nanosheet structure, with its large surface area, provides abundant active sites for electrocatalysis, while the strong interactions between Cu/Fe₃O₄ and Ni Foam enhance electron transfer efficiency. This novel electrode structure demonstrates exceptional electrochemical performance for non-enzymatic glucose sensing, with an ultrahigh sensitivity of 12.85 μA·μM^-1·cm^-2, a low detection limit of 0.71 μM, and a linear range extending up to 1 mM. Moreover, the Cu/Fe₃O₄/NF electrode exhibits excellent stability, a rapid response (~3 s), and good selectivity against interfering substances such as uric acid, ascorbic acid, H₂O₂, urea, and KCl. It also shows strong reliability in analyzing human serum samples. Therefore, Cu/Fe₃O₄/NF holds great promise as a non-enzymatic glucose sensor, and this work offers a valuable strategy for the design of advanced electrochemical electrodes.

β-Ga₂O₃ holds significant promise for use in ultraviolet (UV) detectors and high-power devices due to its ultra-wide bandgap. However, the cost-effective preparation of large-area thin films remains challenging. In this study, β-Ga₂O₃ thin films are prepared using an inorganic solution reaction spin-coating method followed by post-annealing. The structures, surface morphologies, and optical properties of the films are then characterized using X-ray diffraction, scanning electron microscopy, and ultraviolet-visible spectrophotometry. A low-cost Ga metal was used to produce NH₄Ga(SO₄)₂, which was then converted into a precursor solution and spin-coated onto sapphire and quartz substrates. Ten cycles of spin coating produced smoother films, although higher annealing temperatures induced more cracks. The films on the (0001) sapphire subjected to spin-coating and preheating processes that were repeated for ten cycles, followed by annealing at 800 °C, had a preferred orientation in the [-201] direction. All the films showed high transmittances of 85% in ultraviolet-visible light with wavelengths above 400 nm. The films on the (0001) sapphire substrate that were annealed at 800 °C and 1000 °C exhibited bandgaps of 4.8 and 4.98 eV, respectively. The sapphire substrates demonstrated a superior compatibility for high-quality Ga₂O₃ film fabrication compared to quartz. This method offers a cost-effective and efficient approach for producing high-quality β-Ga₂O₃ films on high-temperature-resistant substrates with promising potential for optoelectronic applications.

The unintentional release of nanoparticles in the atmosphere and their targeted application to improve plant productivity requires detailed study. The translocation features of copper and gold nanoparticles applied by spraying in the concentration range of 1-100 mg/L in Petroselinum crispum (Mill.) tissues during a 10-day experiment were investigated. Atomic absorption spectrometry and inductively coupled plasma atomic emission spectroscopy showed that copper and gold nanoparticles applied to the leaves' surface could accumulate in plant organs. A dose-dependent increase in the content of copper and gold in the aerial parts of parsley was revealed. The content of copper in leaves treated with nanoparticles was 1-2.3 times higher than the control, while the content of gold exceeded control values 2-116 times. The effect of nanoparticles on plants' biochemical composition was assessed. The antioxidant tests showed an ambiguous response at exposure to metal nanoparticles. Copper nanoparticles at the applied concentration consistently reduced both chlorophyll and carotenoid content. Gold nanoparticles enhanced the chlorophyll and carotenoid level at low concentrations (1 mg/L) and significantly inhibited it at higher concentrations. The parsley exposed to nano-copper remained safe for human consumption, but parsley containing more than 14.9 mg/kg of gold may adversely affect human health.

Bacterial cellulose (BC) is a versatile biopolymer prized for its remarkable water absorption, nanoscale fiber architecture, mechanical robustness, and biocompatibility, making it suitable for diverse applications. Despite its potential, the high cost of conventional fermentation media limits BC's scalability and wider commercial use. This study investigates an economical solution by utilizing fractions from fruit processing wastewater, refined through sequential membrane fractionation, as a supplement to commercial HS medium for BC production. BC films were thoroughly characterized using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and assessments of mechanical properties and water holding capacity (WHC). FTIR confirmed the BC structure, while TEM validated its nanofibrillar 3D network. XRD analysis revealed a slight increasing trend in crystallinity with the addition of wastewater fractions, and DSC revealed a slight increase in thermal stability for F#6. Adding these fractions notably improved the BC films' tensile strength, Young's modulus, and WHC. Overall, the results underscore that fruit processing wastewater fractions can serve as a cost-efficient, eco-friendly alternative to traditional fermentation media. This approach supports circular economy principles by lowering reliance on intensive wastewater treatments, promoting waste valorization, and advancing sustainable production methods for high-value biopolymers.

Nanomaterials, including quantum dots, have gained more and more attention in the past few decades due to their extraordinary properties that make them useful for many applications, ranging from catalysis, energy generation and storage, biotechnology, and medicine to quantum informatics. Mathematical descriptions of the phenomena in which nanostructures are involved are of great demand because they may be utilized for the purpose of controlling these phenomena (e.g., the growth of nanostructures with certain sizes, shapes, and other properties). Such models may be of distinct nature, including calculations from first principles, ordinary and partial differential equations, and machine learning models (including artificial intelligence) as well. The aim of this article is to review the most important and useful computational and mathematical approaches for the description and control of processes involving nanostructures.

With the rise in global plastic production and the presence of plastic waste in the environment, microplastics are considered an emerging environmental contaminant. Human exposure and the impact of microplastics on human health are not well studied. Recent studies have observed the presence of microplastics in human tissues and several studies have noted toxicity in in vitro and in vivo mammalian models. We examined the impact of polystyrene nano- and microplastics in increasingly complex intestinal cell models. Using an undifferentiated Caco-2 mono-culture model, we assessed particle association, cytotoxicity, and particle clearance/retention, whereas in differentiated mono- and tri-culture transwell models, we assessed membrane integrity and particle translocation. Only 50 nm and 500 nm particles were internalized in the undifferentiated cells; however, no signs of cellular toxicity were observed at any concentrations tested. Additionally, polystyrene particles had no impact on barrier integrity, but the 50 nm particles were able to cross to the basolateral side, albeit attenuated in the tri-culture model that had a mucus layer. This study reduced some of the variability common to MNPL testing across various in vitro models, but further testing is needed to fully understand the potential effects of human MNPL exposure.

Ceramic materials have the merits of an adjustable dielectric constant, high strength, high temperature resistance, and oxidation resistance, and are thus being used as the protection matrix for carbon series, metal oxides, and other wave-absorbing materials at high temperatures. Here, progress on high-temperature-resistant wave-absorbing ceramic materials is introduced through the aspects of their composition and structure. In addition, metamaterials used for such purposes, which are mainly produced through 3D printing, are also highlighted. The pros and cons of high-temperature-resistant electromagnetic wave absorbers based on ceramic materials are systematically analyzed, and possible development directions are proposed. This work may assist in the design and manufacture of a new generation of radars, ships, and aircraft.

Tattoo inks contain varying amounts of metal nanoparticles (NPs) < 100 nm that, due to their unique physicochemical properties, may have specific biological uptake and cause skin or systemic toxicities. The toxic effects of certified reference standards of metal NPs and samples of commercially available tattoo inks were investigated using an in vitro system and a novel human ex vivo model. In vitro toxicity was evaluated using vitality assays on human skin cells (HaCaT cell line, primary fibroblasts, and keratinocytes). No toxicity was observed for Al₂O₃, Cr₂O₃, Fe₂O₃, and TiO₂ NPs, whereas CuO NPs showed dose-dependent toxicity on HaCaT and primary fibroblasts. Fibroblasts and keratinocytes were also sensitive to high concentrations of ZnO NPs. Reference standards and ink samples were then injected ex vivo into human skin explants using tattoo needles. Histological analysis showed pigment distribution deep in the dermis and close to dermal vessels, suggesting possible systemic diffusion. The presence of an inflammatory infiltrate was also observed. Immunohistochemical analysis showed increased apoptosis and expression of the inflammatory cytokine interleukin-8 in explants specifically tattooed with the reference standard or red ink. Taken together, the results suggest that the tattooing technique leads to exposure to toxic metal NPs and skin damage.

The optical properties of Mn⁵⁺ ions, which are responsible for the intense green-turquoise-blue coloration of Mn⁵⁺-based pigments and the near-infrared emission of phosphors, are the focus of this article. Mn⁵⁺ ions enter crystalline matrices in four-fold coordinated positions and can maintain their 5+ valence state when crystalline hosts meet the conditions described in this work. Mn⁵⁺ ions have [Ar]3d² electronic configuration and always experience a strong crystal field due to a high electric charge; therefore, their lower electronic states have the ³A₂ < ¹E < ¹A₁ < ³T₂ < ³T₁ progression in energy. We present the properties of several Mn⁵⁺-based pigments and discuss the electronic transitions responsible for their coloration. Specifically, we show that the color is determined by the spin-allowed ³A₂ → ³T₁(³F) absorption, which extends across the orange-red-deep red spectral region and is strongly influenced by crystal field strength. The narrow-band emission Mn⁵⁺-activated near-infrared phosphors arise from the spin-forbidden ¹E → ³A₂ transition, whose energy is independent of the crystal field strength and determined by the nephelauxetic effect. We demonstrate the linear relationship between ¹E state energy and the nephelauxetic parameter β₁ using Racah parameter literature data for Mn⁵⁺ phosphors. Lastly, we address the recent applications of these Mn⁵⁺ phosphors in luminescence thermometry.