Beilstein Journal of Nanotechnology最新文献

This work presents a unique and straightforward method to synthesise hafnium oxide (HfO₂) and hafnium carbide (HfC) nanoparticles (NPs) and to fabricate hafnium nanostructures (NSs) on a Hf surface. Ultrafast picosecond laser ablation of the Hf metal target was performed in three different liquid media, namely, deionised water (DW), toluene, and anisole, to fabricate HfO₂ and HfC NPs along with Hf NSs. Spherical HfO₂ NPs and nanofibres were formed when Hf was ablated in DW. Hf ablated in toluene and anisole demonstrated the formation of core-shell NPs of HfC with a graphitic shell. All NPs exhibited novel optical reflectance properties. Reflectance measurements revealed that the fabricated NPs had a very high and broad optical absorption throughout the UV-vis-NIR range. The NPs synthesised in toluene exhibited the best absorption. The successful fabrication of Hf NSs with the formation of laser-induced periodic surface structures (LIPSS) with low spatial frequency (LSFL) and high spatial frequency (HSFL) orthogonal to each other was also demonstrated. The LSFL and HSFL both exhibited quasi-periodicity. This work presents a simple way to fabricate HfO₂ and HfC NPs and provides insight into their morphological and optical characteristics paving way for their applications in future.

In this study, a simulation of the elementary chemical reactions during SiO _x film growth in a hot filament chemical vapor deposition (HFCVD) reactor was carried out using a 2D model. For the 2D simulation, the continuity, momentum, heat, and diffusion equations were solved numerically by the software COMSOL Multiphysics based on the finite element method. The model allowed for the simulation of the key parameters of the HFCVD reactor. Also, a thermochemical study of the heterogeneous reaction between the precursors quartz and hydrogen was carried out. The obtained equilibrium constants (K _eq) were related to the temperature profile in the deposition zone and used in the proposed simulation. The validation of the model was carried out by measuring the temperature experimentally, where the temperature range on the substrate is 450 to 500 °C for different deposition parameters. In the simulation, the laminar flow of species contributing to the film growth was confirmed, and the simulated concentration profiles of H° and SiO near the filaments and the sources were as expected. H° and SiO are essential species for the subsequent growth of the SiO _x films. These SiO _x films have interesting properties and embedded nanostructures, which make them excellent dielectric, optoelectronic, and electroacoustic materials for the fabrication of devices compatible with silicon-based technology.

Biomimetic nanocarriers, engineered to mimic the characteristics of native cells, offer a revolutionary approach in the treatment of various complex human diseases. This strategy enhances drug delivery by leveraging the innate properties of cellular components, thereby improving biocompatibility and targeting specificity. Biomimetic nanocarriers demonstrate significant advancements in drug delivery systems against cancer therapy, Alzheimer's disease, autoimmune diseases, and viral infections such as COVID-19. Here, we address the therapeutic applications of biomimetic nanocarriers and their promising strategy for personalized medicine.

The increasing interests in natural, biodegradable, non-toxic materials that can find application in diverse industry branches, for example, food, pharmacy, medicine, or materials engineering, has steered the attention of many scientists to plants, which are a known source of natural hydrogels. Natural hydrogels share some features with synthetic hydrogels, but are more easy to obtain and recycle. One of the main sources of such hydrogels are mucilaginous seeds and fruits, which produce after hydration a gel-like, transparent capsule, the so-called mucilage envelope. Mucilage serves several important biological functions, such as supporting seed germination, protecting seeds against pathogens and predators, and allowing the seed to attach to diverse surfaces (e.g., soil or animals). The attachment properties of mucilage are thus responsible for seed dispersal. Mucilage represents a hydrophilic, three-dimensional network of polysaccharides (cellulose, pectins, and hemicelluloses) and is able to absorb large amounts of water. Depending on the water content, mucilage can behave as an efficient lubricant or as strong glue. The current work attempts to summarise the achievements in the research on the mucilage envelope, primarily in the context of its structure and physical properties, as well as biological functions associated with these properties.

Thanks to their simple synthesis, controlled physical properties, and minimal toxicity, iron oxide nanoparticles (Fe₃O₄ NPs) are widely used in many biomedical applications (e.g., bioimaging, drug delivery, biosensors, diagnostics, and theranostics). However, the use of NPs does not preclude the possibility of selective toxicity and undesirable effects, including accumulation in tissues and direct interaction with specific biological targets. This study evaluated the biocompatibility of Fe₃O₄ NPs, Teucrium polium (T. polium) extract, rutin, and the corresponding complexes on the liver tissue of healthy white Wistar rats. The impact profile of the synthesized Fe₃O₄ NPs (15 ± 4 nm), rutin, T. polium extract, and their complexes on biochemical markers of liver function (ALT, AST, ALP, GGT, HDL, LDL, total cholesterol, total protein, and albumin) and morphological indicators of rat liver was investigated. Fe₃O₄ NPs, rutin, and T. polium extract do not show direct hepatotoxicity when administered intraperitoneally to rats, unlike their complexes. All agents exert a hypolipidemic effect by lowering LDL, despite maintaining the synthetic functions of the liver. Fe₃O₄ NPs increase the activity of GPO, which is associated with their peroxidase-like properties. A multifaceted and diverse mechanism of action of all studied samples on the liver of Wistar rats was identified.

ʟ-Carnosine is a dipeptide with notable antioxidant, antiglycation, metal chelating, and neuroprotective properties. Despite its many biological roles, applying ʟ-carnosine as a capping agent in nanoparticle synthesis has remained underexplored. This study explores the potential of ʟ-carnosine in synthesizing tunable plasmonic silver nanoparticles (ʟ-car-AgNPs). The formation of ʟ-car-AgNPs was confirmed via UV-vis optical absorption spectroscopy, showing single and double plasmonic peaks, depending on the synthesis conditions. Physicochemical characterization using TEM, FTIR, and Raman spectroscopy, as well as EDX and XRD revealed controlled aggregation, successful capping, and crystalline growth of the ʟ-car-AgNPs. The ʟ-car-AgNPs exhibited promising sensing capabilities with limits of detection of 141.79 ppb (1.2 μM) for Cd²⁺, 131.33 ppb (0.63 μM) for Pb²⁺, 215.35 ppb (2.8 μM) for As³⁺, and 245.49 ppb (4.7 μM) for Cr³⁺. Additionally, these nanoparticles demonstrated catalytic activity regarding the degradation of p-nitrophenol (P-NP), achieving complete degradation of 0.25 and 1 mM solutions within 5 and 10 min, respectively. This study reveals the potential of ʟ-car-AgNPs for both heavy metal ion detection and catalytic degradation of P-NP, indicating their suitability for environmental monitoring and remediation applications. Further optimization and research are needed to expand their environmental applications and to understand their interaction mechanisms with various contaminants.

Mosquito vectors such as Aedes spp. are responsible for the transmission of arboviruses that have a major impact on public health. Therefore, it is necessary to search for ways to control these insects, avoiding the use of conventional chemical insecticides that are proven to be toxic to nature. In the last years, there has been growing evidence for the potential of silver nanoparticles (AgNPs) to be ecologically benign alternatives to the commercially available chemical insecticides against vector-borne diseases. Natural seaweed extracts contain metabolites such as polyphenols, terpenoids, and alkaloids. These compounds act as reducing agents and stabilizers to synthesize biogenic AgNPs. The green synthesis of AgNPs has advantages over other methods, such as low cost and sustainable biosynthesis. In the perspective of using AgNPs in the development of novel insecticides for vector control, this review deals with the eco-friendly synthesis of AgNPs through seaweed extracts as reducing and stabilizing agents. In addition, assessment of toxicity of these nanomaterials in non-target species is discussed.

We studied the ultrastructure of the ultrablack cuticle in Traumatomutilla bifurca, an enigmatic and visually striking species of velvet ants (Hymenoptera, Mutillidae). Using a combination of scanning electron microscopy (SEM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), and optical spectroscopy, we conducted a comprehensive analysis of the cuticle to elucidate its unique optical properties. SEM imaging provided a detailed surface morphology, while TEM provided insights into the internal structure. CLSM showed that the cuticle exhibits no autofluorescence. Our findings reveal a highly specialized cuticle, characterized by microstructures that effectively minimize reflectance and enhance light absorption. Optical spectrometry confirmed the ultrablack nature of the cuticle, with the measured reflectance approaching minimal levels across a broad spectrum of wavelengths. Therefore, our study contributes to a deeper understanding of ultrablack biological materials and their potential applications in biomimetics.

A key step in building regulatory acceptance of alternative or non-animal test methods has long been the use of interlaboratory comparisons or round-robins (RRs), in which a common test material and standard operating procedure is provided to all participants, who measure the specific endpoint and return their data for statistical comparison to demonstrate the reproducibility of the method. While there is currently no standard approach for the comparison of modelling approaches, consensus modelling is emerging as a "modelling equivalent" of a RR. We demonstrate here a novel approach to evaluate the performance of different models for the same endpoint (nanomaterials' zeta potential) trained using a common dataset, through generation of a consensus model, leading to increased confidence in the model predictions and underlying models. Using a publicly available dataset, four research groups (NovaMechanics Ltd. (NovaM)-Cyprus, National Technical University of Athens (NTUA)-Greece, QSAR Lab Ltd.-Poland, and DTC Lab-India) built five distinct machine learning (ML) models for the in silico prediction of the zeta potential of metal and metal oxide-nanomaterials (NMs) in aqueous media. The individual models were integrated into a consensus modelling scheme, enhancing their predictive accuracy and reducing their biases. The consensus models outperform the individual models, resulting in more reliable predictions. We propose this approach as a valuable method for increasing the validity of nanoinformatics models and driving regulatory acceptance of in silico new approach methodologies for the use within an "Integrated Approach to Testing and Assessment" (IATA) for risk assessment of NMs.

A novel electrochemical sensor for the detection of enrofloxacin (ENR) in aqueous solutions has been developed using a carbon paste electrode modified with a mixture of metal-organic frameworks (MOFs) of CuBTC and FeBTC. These MOFs were successfully synthesized via a solvothermal method and characterized using various techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and X-ray photoelectron spectroscopy. The MOF mixture exhibited a particle size ranging from 40 to 100 nm, a high surface area of 1147 m²/g, a pore volume of 0.544 cm³/g, and a capillary diameter of 1.50 nm. Additionally, energy-dispersive X-ray mapping demonstrated the uniform distribution of the two MOFs within the electrode composition. The synergistic effect of the electrocatalytic properties of CuBTC and the high conductivity of FeBTC significantly enhanced the electrochemical response of ENR, increasing the signal by more than ten times compared to the unmodified electrode. Under optimal analytical conditions, the sensor exhibited three dynamic ranges for ENR detection, that is, 0.005 to 0.100 µM, 0.1 to 1.0 µM, and 1 to 13 µM, with coefficients of determination of 0.9990, 0.9954, and 0.9992, respectively, depending on the accumulation duration. The sensor achieved a low detection limit of 3 nM and demonstrated good reproducibility, with a relative standard deviation of 3.83%. Furthermore, the sensor demonstrated effective performance in analysing tap and lake water samples, with recovery rates ranging from 90.2% to 121.3%.