Applied Nano

Dimethyl phthalate (DMP) is an environmental contaminant known for its endocrine-disrupting properties, and its removal poses a critical environmental challenge. In this paper, we present a theoretical study of the adsorption of the DMP molecule and its isomers on pristine and nitrogen-doped graphitic surfaces, which represent the pore walls of nanoporous activated carbon, using density functional theory (DFT) calculations. Detailed wavefunction analyses were performed to elucidate the nature of adsorption on the AC surfaces. Our results reveal that nitrogen doping improves phthalate adsorption in the following order: AC-Pristine < AC-NH₂ < AC-Graphitic-N < AC-Graphitic-2N. This enhancement arises from changes in charge distribution that introduce electrostatic interactions between the COOCH₃ groups of the molecules and nitrogen-doped atoms on the AC surface. This study provides mechanistic insights into DMP adsorption on nitrogen-doped AC and offers rational guidelines for designing efficient carbon-based adsorbents for the removal of phthalate esters from contaminated water and the environment. Full article

Altermagnets combine compensated magnetic order with momentum-dependent spin splitting, enabling Berry-curvature control without net magnetization. Here we investigate mechanically driven altermagnet–topological-insulator (AM/TI) interfaces in which periodic modulation of the crystalline phase selectively renormalizes the cycle-averaged interfacial exchange harmonics through exact Bessel-function averaging. The resulting harmonic-selective control introduces a new tuning parameter—the drive amplitude—that continuously reshapes the angular mass texture and enables re-entrant transitions between distinct topological sectors. Using continuum Berry-curvature calculations, we show that amplitude-controlled modulation of the twofold and fourfold exchange harmonics produces topological switching, Hall-conductivity suppression near Bessel zeros, and enhanced thermoelectric responses. Cyclic driving protocols further generate nontrivial winding trajectories in the experimentally accessible two-mass control plane, providing a geometric characterization of adiabatic modulation cycles through a winding invariant. To establish the topological character of the predicted phases, the continuum results are independently validated using compact Brillouin-zone lattice regularization, gauge-invariant Fukui–Hatsugai–Suzuki Chern-number calculations, and open-boundary ribbon spectra. The proposed mechanism operates in the adiabatic regime accessible to piezoelectric and surface-acoustic-wave actuation at MHz frequencies and is compatible with strain-tunable AM/TI heterostructures at cryogenic temperatures. These results identify mechanically driven AM/TI interfaces as a platform for programmable topological transport and harmonic-selective Berry-curvature engineering. Full article

Modern aquaculture is essential for meeting the increasing global demand for fish and seafood, but its rapid expansion has exposed limitations that threaten long-term sustainability. Major challenges include high disease outbreaks, low nutritional efficiency, and the instability and poor solubility of nutraceuticals and plant-derived compounds. These challenges often create a self-reinforcing feedback loop, amplifying the detrimental effects of one another. Conventional approaches, including antibiotics, chemical treatments, aquafeeds, and chemotherapeutic agents, have shown limited effectiveness, partly due to inefficient delivery systems that can contribute to environmental contamination and antimicrobial resistance. This review discusses nanotechnology-enabled strategies to improve these traditional methods, focusing on nanocarriers and nanoencapsulation techniques, and also mentioning other synthetized nanoparticles and microencapsulation strategies. These systems have succeeded in reducing oxidative degradation and improving bioavailability by enhancing the stability and activity of encapsulated bioactives. The review also evaluates their functional performance, limitations, environmental effects, interactions with different organisms, and regulatory constraints in the industry. Overall, while safe and scalable use of biodegradable nanoscale delivery systems in modern aquaculture has shown great potential, it still depends on careful design, harmonized regulations, and economically feasible manufacturing. Full article

Silicon carbide (SiC) is the leading wide-bandgap semiconductor material, providing mature doping and device fabrication. Additionally, SiC hosts a multitude of optically active point defects (color centers) and is relevant for many applications in quantum technologies. A crucial step towards harnessing the full potential of the SiC platform includes technologies to create color centers with defined localization and density, e.g., to facilitate their coupling to nano-photonic structures and to observe cooperative effects. Here, silicon vacancy centers and divacancies stand out, as no impurity atom is needed, and high-thermal budget annealing steps can be avoided. We characterize the effect of localized, femtosecond laser irradiation of SiC, investigating surface modifications and photoluminescence, including Raman spectroscopy and optical lifetime measurements. We employ commercial, high-purity, semi-insulating substrates and an industrial-grade laser system to explore broader applicability of the method. As a novel approach, we apply femtosecond laser irradiation to SiC substrates with an epitaxial graphene layer and find that the threshold for photoluminescence due to laser treatment is lowered. Full article

The present work analyzes light propagation in asymmetric waveguides with dielectric cores and anisotropic multilayer claddings based on nanometric planar hyperbolic metamaterials. A generalized definition of asymmetry, incorporating both structural and physical parameters, is introduced by varying metal composition and filling ratios in the claddings. The influence of wavelength, material permittivity, metal filling fraction, and core thickness on surface wave modes is examined using effective medium theory and considering experimentally derived material data. Propagation distances on the order of 400 µm have been achieved for optimized waveguide configurations operating within the C-band used in optical telecommunications. Full article

Supercapacitors are widely used in high-power-density applications due to their ability to deliver rapid energy bursts and fast recharging. The incorporation of naturally derived materials into supercapacitor electrodes offers notable advantages in terms of sustainability, environmental impact, and biodegradability relative to their synthetic counterparts. In this study, activated carbon with high electronic conductivity is combined with pyrolyzed sucrose as a binder to fabricate thin-film electrodes, with 2.50 mol dm⁻³ H₂SO₄ serving as the electrolyte. Both constituent materials are characterized with respect to their structural and electrical properties. The optimized electrodes exhibit a sheet resistance of 171.24 Ω sq⁻¹ and a resistivity of 1.92 × 10⁻⁴ Ω cm. The assembled electric double-layer capacitor achieves a specific capacitance of 74.35 F g⁻¹ at an activated carbon-to-sucrose ratio of 1:2, following sintering at 350 °C for 20 min. Cyclic voltammetry reveals capacitive-to-diffusive current contributions of 93:7% at 200 mV s⁻¹ and 67:33% at 5 mV s⁻¹, with a specific capacitance retention of 77% after 1000 cycles. Collectively, these results indicate that the fabricated electrodes possess satisfactory energy storage capability and adequate electrochemical stability. The findings suggest that biomass-derived activated carbon–pyrolyzed sucrose composites warrant consideration as cost-effective and environmentally benign electrode materials for sustainable energy storage applications. Full article

Hydrogen peroxide (H₂O₂) is a key reactive oxygen species involved in both cellular signaling and oxidative stress, making its reliable detection essential in biological and environmental systems. Electrochemical sensing has emerged as a promising approach for H₂O₂ monitoring due to its high sensitivity, rapid response, and suitability for in situ analysis. This review provides a comprehensive overview of nanostructured metal oxide electrodes for non-enzymatic electrochemical detection of H₂O₂. The effects of material composition, nanostructure morphology, and synthesis strategies (particularly hydrothermal methods) on sensor performance are critically discussed. Special attention is given to our previously reported studies, enabling a consistent comparison of structure–property relationships under similar experimental conditions. Furthermore, the application of these sensors in plant stress analysis is examined, including both the monitoring of oxidative stress and the evaluation of stress mitigation strategies using metal oxide nanoparticles. The role of nanoparticles as reactive oxygen species scavengers and enhancers of plant antioxidant systems is highlighted, demonstrating their ability to reduce H₂O₂ levels and improve plant physiological status under adverse environmental conditions. Overall, this work emphasizes the dual functionality of nanostructured materials as both sensing platforms and active agents for stress mitigation, highlighting their potential in agricultural and environmental applications. Full article

PVP-stabilized silver nanoparticles (Ag NPs) were functionalized with sildenafil (Sil), leading to spherical NPs (Ag@Sil NPs) with a size of about 30 nm as observed through transmission electron microscopy and dynamic light scattering. Fourier-transformed IR spectroscopy confirmed the covering of the particles with Sil. The Ag@Sil NPs were incorporated into a 0.1 wt% ointment and tested for the treatment of acute anal fissures in a preliminary medical study involving 50 patients. Typical symptoms such as pain, bleeding, itching, and mass sensation were improved in the intervention group with no adverse effects. Molecular docking showed strong interactions with docking scores slightly above −10 kcal/mol between sildenafil and two different model complexes [Ag–Sil]⁺ for the Ag-bound sildenafil with either piperazine-N- or pyrazole-N-bound Ag⁺ ions and the muscarinic M2 and the nicotinic acetylcholine α3β4 receptor, which are both involved in anal sphincter regulation. All three showed superior binding compared with nitroglycerin and L-arginine. The residue analysis revealed a higher number of relevant interactions for the sildenafil and the two Ag⁺ complexes, compared to nitroglycerin and L-arginine, fully in line with the differences in the docking scores. Full article

The built-in electric field induced by polarization in ZnO/Mg_0.2Zn_0.8O quantum wells can be screened to modulate the conduction-band potential profile and intersubband energy levels. To optimize the screening of the built-in electric field, we analyze the influence of an external electric field, temperature, and modulation doping. The position of the doped layer is varied within the heterostructure to improve field compensation, providing additional control over electron localization and intersubband energy separation. In this work, within the effective mass approximation and by self-consistently solving the Poisson and Schrödinger equations using the finite-difference method, we calculate the electronic structure and nonlinear optical response of an n-type doped ZnO/Mg_0.2Zn_0.8O quantum well heterostructure. Our results indicate a strong dependence of the confinement potential on the applied external electric field and the electrostatic potential arising from the doped layer. We demonstrate electronic Raman gain values on the order of ${10}^3$–${10}^4$ cm⁻¹ for specific values of field strength, temperature, and doped-layer position. This approach enables fine-tuning of the nonlinear optical response, which is crucial for the development of ZnO-based optoelectronic devices. Full article

Hybrid organic–inorganic composites based on biopolymers and nanoclays are attracting increasing interest for the development of functional materials in biomedical and agricultural applications. In this work, elongated alginate/halloysite nanotube (Alg/HNT) composite filaments were fabricated through a wet-spinning process assisted by syringe-based extrusion. Alg/HNT dispersions with different inorganic/organic ratios were first screened in terms of colloidal stability and injectability in order to identify suitable formulations for extrusion. The influence of key processing parameters, including the extrusion flow rate and calcium chloride concentration in the coagulation bath, was then systematically investigated to elucidate their effect on filament morphology and structure. Optical and scanning electron microscopy revealed that filament diameter can be tuned by varying the CaCl₂ concentration, while partial alignment of alginate chains along the extrusion direction was observed. Halloysite nanotubes were homogeneously distributed within the polymer matrix, mainly as micro-sized aggregates. Finally, the nanotubes were chemically functionalized with caffeine, as a model molecule, and incorporated into the alginate filaments, demonstrating the feasibility of introducing specific functionalities into wet-spun Alg/HNT composite fibers. These results establish a reproducible strategy for the fabrication of alginate/HNT filaments with tunable morphology and functionalizable nanotube interfaces, providing a versatile platform for the development of sustainable hybrid biopolymer materials. Full article

Introduction: Silver diamine fluoride (SDF) is a colorless solution used at different concentrations. It is a topical treatment used on caries lesions having as its main properties being cariostatic, remineralizing and antibacterial. Nanosilver fluoride (NSF) is effective as a cariostatic without a staining effect on the tooth surface as in the case of SDF, which generates a black stain on the treated surface. This NSF has been shown to exhibit low toxicity and continue to exhibit antimicrobial properties. Purpose: To compare the antibacterial effect of silver diamine fluoride and nanosilver fluoride against Streptococcus mutans. Methods: The NSF was prepared by starting with the synthesis of silver nanoparticles with chitosan and then adding it to a sodium fluoride (NaF) solution. The compared groups were SDF, NSF, AgNPs, NaF, and chlorhexidine. The antibacterial effect will be measured using the Kirby–Bauer microbiological technique. Results: The analysis of results was obtained using the ANOVA statistical test. A significant difference was obtained in the comparison between the groups with a value of p = 0.001. Subsequently, Tukey’s test was applied, obtaining significant differences between all the groups compared against the SDF, obtaining greater results in this group. Conclusions: Both silver diamine fluoride and nanosilver fluoride exhibit strong antibacterial activity at commercially recommended concentrations, supporting their use as optimal dental materials in both interceptive and preventive caries treatments. Full article

Clove essential oils (CEOs) are widely studied because of their biological potential; however, their applications are limited because of their water immiscibility. Microemulsions (MEs) can protect, deliver, and enhance the biological activities of CEOs, including their antioxidant and cytotoxic activities. In this research, the effects of ethanol as a cosurfactant and the polysorbate 80:cosurfactant mixture (S_mix = 1:0, 9:1, 7:1, 5:1, 3:1, and 1:1) on the formation of CEO-MEs were evaluated via a pseudo-ternary phase diagram. After 35 days, all the systems produced clear, monodisperse, and thermodynamically stable MEs, characterized by average sizes below 25.6 nm and low polydispersity index values (<0.21). The S_mix dose–response experiments without CEO revealed that the S_mix ratios of 1:1 and 3:1 resulted in the lowest cytotoxicity to HT-29 (colorectal adenocarcinoma) cells. The antioxidant capacity of the CEO-ME was greater than that of the CEO. Finally, the CEO-MEs enhanced the in vitro cytotoxic activity of the CEO against Caco-2, HT-29, HeLa, PC-3, and A549 cancer cells. These findings provide valuable information for the development of low-energy clove essential oil MEs for potential incorporation into functional foods and pharmaceutical products. Full article

The development of biocompatible functional nanostructures has emerged as a key driver in advancing nanomedicine, environmental remediation, and sustainable energy technologies. However, conventional synthesis methods often rely on toxic reagents, hazardous solvents, and energy-intensive processes, raising significant concerns regarding environmental impact and biological safety. In this context, green synthesis has gained increasing attention as a sustainable alternative, utilizing biological systems, renewable resources, and environmentally benign solvents to produce functional nanomaterials. This mini-review provides an overview of recent advances in the green synthesis of organic, inorganic, and hybrid nanostructures, highlighting their physicochemical properties and functional performance. Particular emphasis is placed on their applications in nanomedicine, including drug delivery, bioimaging, antimicrobial and anticancer therapies, and theranostic platforms. Additionally, their roles in environmental applications, such as pollutant degradation and water treatment, and in energy-related systems, including catalysis, solar energy conversion, and energy storage, are discussed with selected representative examples. Despite significant progress, key challenges remain, including limited mechanistic understanding, reproducibility issues, scalability constraints, and uncertainties related to long-term toxicity and environmental impact. Addressing these limitations will be essential for the safe and large-scale implementation of green nanotechnology. Overall, the integration of green chemistry principles with advanced nanomaterial design offers a promising pathway toward the development of multifunctional, sustainable, and high-performance nanostructures capable of addressing global health, environmental, and energy challenges. Full article

This study investigates the hydrothermal modification of commercial titanium dioxide (TiO₂) in the presence of a natural licorice root extract (Glycyrrhiza glabra L.), serving as a stabilizing and growth-modulating agent. The experimental framework combines hydrothermal treatment in a Teflon-lined autoclave with subsequent thermal calcination to elucidate the structural, morphological, and chemical evolution of the material. The plant-based extract significantly influences particle assembly during synthesis, fostering the formation of an initial organic–inorganic hybrid system that results in enhanced morphological homogeneity compared to pristine TiO₂. Thermal analyses (TGA and DSC) demonstrated the progressive decomposition of the organic components with increasing temperature, yielding a thermally stable, predominantly inorganic material at 600 °C. Scanning Electron Microscopy (SEM) observations confirmed a more uniform particle distribution in the modified samples. X-ray diffraction (XRD) patterns corroborated that the primary crystalline phase of TiO₂ remains intact across all conditions, with structural variations limited to peak definition and long-range organization. Furthermore, FTIR spectroscopy supported the preservation of characteristic TiO₂ vibrational features while indicating a gradual depletion of weakly bound surface species following thermal treatment. In conclusion, these findings demonstrate that natural extracts can effectively function as growth-modulating agents, steering material organization without altering its intrinsic chemical properties. This approach aligns with the principles of Green Chemistry and the circular economy, highlighting the potential of renewable plant-based resources as functional additives for the sustainable processing of inorganic materials. Rather than seeking to outperform commercial benchmarks, this work establishes a viable and low-environmental-impact strategy for morphological and structural modulation. Full article

Copper functions as an exceptionally efficient conductor, garnering considerable interest in electrical and thermal applications; however, its relatively malleable nature and insufficient durability may hinder its structural effectiveness. This study focused on the development of copper-based nanocomposites by reinforcing a copper matrix with co-precipitated CuO/Al₂O₃ nanoparticles (varying from 0 to 10 wt% in increments of 2%). A thorough examination was conducted regarding the microstructural characteristics, mechanical properties, and the electrical and thermal conductivities of the composites. X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) analysis validated the successful synthesis of nano-sized CuO and Al₂O₃ phases, with an estimated crystallite size of 33.2 ± 2.4 nm. Scanning electron microscopy revealed a relatively uniform distribution of nano-oxides within the copper matrix, albeit with signs of particle agglomeration at higher loading levels. The durability of the copper exhibited a significant enhancement attributed to the nano-oxide reinforcement, achieving an 180% increase relative to pure copper with a 10% reinforcement addition. Consequently, the tensile strength increased by approximately 68% (from around 154 MPa to nearly 260 MPa), while maintaining an exceptional level of ductility. The electrical conductivity of copper remained largely unchanged with the addition of nanoparticles; rather, a slight improvement in conductivity and a ~30% rise in thermal conductivity were observed at the maximum reinforcement level. This research work presents a copper-based nanocomposite that offers remarkable potential for applications requiring enhanced strength, wear resistance, and exceptional electrical and thermal conductivity. Full article

The commercialization of V-based catalysts for the selective catalytic reduction of NOx by NH₃ (NH₃-SCR) is hindered by their narrow operating temperature window, insufficient low-temperature (LT) activity, and severe SO₂-to-SO₃ oxidation. To bridge this gap, we herein introduced Nb and hexagonal BN into a VW/TiO₂ system to simultaneously enhance its LT SCR activity, suppress undesired side reactions, and improve durability. Nb incorporation promoted V⁵⁺/V⁴⁺ redox cycling and enhanced lattice oxygen mobility, thus reducing the apparent activation energy and suppressing SO₂ oxidation at elevated temperatures. However, excessive Nb loading induced NH₃ oxidation and N₂O formation. This drawback was mitigated by introducing BN as a dispersion promoter, which helped secure high catalytic performance at a reduced Nb content. The VWNb/Ti-BN catalyst achieved superior NOx conversion and N₂ selectivity over a wide temperature range and benefited from notably suppressed NH₃ oxidation and SO₂-to-SO₃ oxidation. Kinetic analysis revealed that Nb primarily lowered the reaction energy barrier via redox property enhancement, whereas BN accelerated surface reaction turnover by stabilizing and dispersing active acidic sites, markedly increasing the turnover frequency without reducing the activation energy. In situ spectroscopic analysis confirmed the accelerated consumption of adsorbed NH₃ species and enhanced formation of reactive NOx intermediates, indicating SCR pathway enhancement. After aging in the presence of SO₂ and H₂O, the best-performing honeycomb-type monolithic catalyst retained and NOx conversion of >80%, demonstrating excellent long-term durability under practical conditions. A composition-aware machine learning model based on log-ratio-transformed variables quantitatively identified the synergistic balance among V, Nb, W, BN, and TiO₂ as the dominant factor governing LT SCR performance. Thus, this work provides valuable mechanistic insights and a strategy for designing wide-temperature-window SCR catalysts with improved activity, selectivity, and resistance to sulfur poisoning. Full article

Currently, titanium dioxide films are widely used as the electron transport layer material in perovskite solar cells. An alternative to titanium dioxide for this role could be niobium pentoxide (Nb₂O₅), an n-type conducting semiconductor oxide. However, the application of Nb₂O₅ in perovskite solar cells is hindered by a lack of data on its electron transport properties, electrophysical parameters, and current–voltage characteristics. Amorphous niobium pentoxide films were obtained by magnetron sputtering. To study their electrical and capacitive properties, a structure of heavily doped n⁺-silicon (n⁺)/niobium oxide/aluminum was used. Based on the analysis of the I–V curves, it was concluded that for a sample at 25 °C, the electron mean free path is greater than the width of the Schottky barrier layer, allowing electrons to pass through this layer without collisions. At temperatures of 35 °C and higher, electrons experience numerous collisions within the Schottky barrier layer. The height of the Schottky barrier for the contact between niobium pentoxide and aluminum was determined. The obtained capacitance frequency plots were explained using the concepts of dipole-relaxation polarization in a dielectric, where electric dipoles can reorient in an external electric field. It has been shown that the use of magnetron sputtering to produce amorphous niobium pentoxide films leads to a reduction in the effective Schottky barrier height. This allows for high electron injection density at low voltages when using such an oxide semiconductor as an electron transport layer, thereby potentially increasing the efficiency of solar cells. Full article

Amorphous calcium phosphate (ACP), a key calcium-phosphorus compound, has been widely applied in fields such as dentistry, orthopedics, and biomedicine. However, its potential for removing copper ions from aqueous solutions remains largely unexplored. In this study, sodium citrate-stabilized amorphous calcium phosphate (Cit-ACP) and its calcined derivatives at various temperatures were successfully synthesized as adsorbents for copper ions. The adsorption behavior of Cit-ACP was best described by the Langmuir isotherm, with kinetics following a pseudo-second-order model. Under conditions of pH 5.5 and an initial copper ion concentration of 200 mg/L, Cit-ACP exhibited a maximum adsorption capacity of 323.96 mg/g. Thermodynamic analysis confirmed that the adsorption process was spontaneous and endothermic. Comprehensive characterization via XRD, XPS, and zeta potential measurements before and after adsorption revealed a two-stage adsorption mechanism. At low initial copper concentrations, adsorption occurred predominantly through surface complexation between copper ions and sodium citrate molecules on Cit-ACP nanoparticles. At higher concentrations, the mechanism extended to include co-precipitation of copper ions with hydroxyl groups, which promoted the transformation of Cit-ACP into copper-substituted calcium phosphate phases, such as copper-containing hydroxyapatite. Owing to its straightforward synthesis, high adsorption capacity, and inherent biocompatibility, Cit-ACP presents a promising, cost-effective, and efficient adsorbent for the removal of copper ions from aqueous environments. Full article

The utilization of biopolymers as raw materials for the development of sustainable materials has become one of the most promising strategies to minimize the negative impact of plastic pollution. Tubers such as purple yam are rich in starch, which serves as the main component for producing strong and durable bioplastics with properties comparable to conventional plastics. In this study, purple yam flour was used as a raw material to develop a biodegradable film through the casting method. Additionally, Flour Nanoparticles (FN) extracted via the Aqueous Counter Collision technique were incorporated to enhance the mechanical, morphological, and barrier properties of the films. The nanoparticles exhibited sizes below 100 nm, as determined by DLS analysis. The casting process was carried out using film solutions containing 2 wt% flour and 15 wt% glycerol, with FN concentrations of 5 wt%, 15 wt%, and 25 wt%. The main results showed that the films with 25 wt% FN displayed improved mechanical strength, increasing from 2.2 MPa (control) to 7.3 MPa, as well as enhanced thermal resistance, rising from 68 °C (control) to 102 °C. The films also exhibited a smoother morphology, indicating improved water vapor transmission (WVT). The incorporation of FN thus contributed to the development of films with reduced hydrophobicity. Full article