Search Results (377)

This study presents a comparative analysis of the effect of methylene blue (MB) loading strategy on the physicochemical and colloidal properties of ethosomes prepared by the cold method. Two synthesis protocols differing in the phase of introduction of the cationic hydrophilic dye were investigated: a classical approach with MB loading into the aqueous phase and an alternative approach involving MB incorporation into the ethanolic lipid phase. It is shown that the loading strategy is a critical technological factor determining vesicle size, encapsulation efficiency, loading capacity, and electrokinetic properties of the systems. The alternative method results in the formation of smaller ethosomes (R_h ≈ 78 nm) compared to the classical protocol (R_h ≈ 96 nm), but is accompanied by a lower encapsulation efficiency (EE ≈ 36% versus 48%). The results indicate that a reduction in vesicle size does not necessarily lead to higher encapsulation of hydrophilic cationic MB and may be associated with a decrease in the total internal aqueous volume as well as an increased contribution of a weakly bound surface-associated dye fraction. Spectral analysis indicates the preservation of a predominantly monomeric form of MB within ethosomes, while differences in ζ-potential suggest distinct localization of the dye within the vesicular systems. Overall, the results highlight the importance of optimizing the loading protocol in the development of ethosomal drug delivery systems for photodynamic therapy and topical applications. Full article

CsPbBr₃ perovskite quantum dots (QDs) have attracted significant attention for optoelectronic applications owing to their outstanding optical properties, yet achieving controlled synthesis with high stability under mild conditions remains a challenge. The room-temperature synthesis of CsPbBr₃ perovskite quantum dots using a coprecipitation method is systematically investigated in this work, with an emphasis on how the structural and optical properties of the QDs are influenced by the Br/Pb ratio and OA/OAm ratio. The findings show that controlling the Br/Pb and OA/OAm ratios can effectively influence the size, crystalline phase, and surface passivation properties of CsPbBr₃ quantum dots. The photoluminescence peak shifts blue and the bandgap widens when the Br/Pb ratio rises due to a decrease in quantum dot size. This is mainly explained by more effective surface covering by Br⁻ ions and increased quantum confinement effects. The resultant quantum dots demonstrate ideal optical performance at a Br/Pb ratio of 75 and an OA/OAm ratio of 1.5, with dense ligand coverage, superior defect passivation, and markedly improved stability under UV irradiation and in aqueous environments. Variations in the Br/Pb and OA/OAm ratios affect the binding configuration and coverage of ligands on the quantum dot surface, thereby influencing the relationship between non-radiative recombination and the quantum confinement effect. The LED fabricated with the as-synthesized high-performance quantum dots demonstrates a wide color gamut, covering 129.45% of the NTSC standard, indicating strong potential for display applications. 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 increasing demand for environmentally benign inorganic pigments has stimulated interest in sustainable synthesis routes for iron oxide nanoparticles that minimize toxic reagents and energy-intensive processing. In this study, a plant-mediated approach for the synthesis of hematite (α-Fe₂O₃) nanoparticles using Spinacia oleracea (spinach) leaf extract is presented, with particular emphasis on pigment-relevant material characteristics. An aqueous spinach extract was employed as a natural reducing and stabilizing medium for ferric ions under ambient conditions. The formation of iron oxide nanoparticles was indicated by a characteristic color change and confirmed by structural and morphological characterization. X-ray diffraction revealed phase-pure crystalline hematite, while transmission electron microscopy showed quasi-spherical nanoparticles with sizes in the range of 20–50 nm. The synthesis avoids hazardous chemicals, high-temperature calcination, and organic solvents, offering a low-energy and environmentally compatible route. Although the yield per batch is modest, the simplicity, non-toxicity, and pigment-suitable properties of the synthesized nanoparticles highlight the potential of this method for sustainable pigment and coating applications. Full article

Metal–organic frameworks (MOFs), particularly Zeolitic Imidazolate Framework-8 (ZIF-8), are promising photocatalysts; however, their practical application is limited by a wide band gap (~3.85 eV), which restricts light absorption mainly to the ultraviolet region. This limitation was addressed by synthesizing a series of cobalt-doped ZIF-8 materials, Co(x)ZIF-8 (x = 0, 2.5, 5, 7.5, and 10 wt%), using a cost-effective aqueous synthesis route. Structural and compositional analyses using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS) confirmed the formation of phase-pure ZIF-8 topology, with no significant change in nanoparticle morphology upon the partial substitution of Zn²⁺ by Co²⁺ ions within the framework. UV–Vis diffuse reflectance and Tauc plot analysis revealed a systematic and substantial reduction in the optical band gap (Eg) with increasing Co content, indicating enhanced visible-light absorption capability. All Co(x)ZIF-8 samples exhibited superior photocatalytic activity compared to pristine ZIF-8 under light irradiation. Among them, Co(2.5)ZIF-8 displayed the highest apparent reaction rate constant for pollutant degradation, while Co(5)ZIF-8 achieved the highest overall degradation efficiency (~87%) after 40 min. The enhanced photocatalytic performance is attributed to the synergistic effects of band-gap narrowing and the presence of Co²⁺ ions, which act as effective charge-trapping centers and suppress electron–hole recombination. Electrochemical measurements further demonstrated that Co(5)ZIF-8 exhibits the highest current density (most negative J) at large negative potentials (e.g., J ≈ −0.105 A cm⁻² at E = −2.0 V), indicating superior intrinsic catalytic activity. These findings highlight cobalt-doped ZIF-8 as a highly tunable and efficient photocatalyst with strong potential for environmental remediation applications. Full article

The trend toward developing sustainable nanotechnology has driven researchers to explore environmentally friendly techniques for nanomaterial fabrication. This review examines the utilisation of Commelina benghalensis plant extracts as an effective biological tool for the green synthesis of various nanomaterials. The procedures involve reducing metal salt precursors with aqueous or polar solvent extracts rich in phytochemicals such as flavonoids and polyphenols, followed by a calcination step that yields crystalline products. The findings show that the properties of ZnO, TiO₂, Ag, NiO, and their composites are directly influenced by synthesis factors, including solvent, plant component, and extract concentration. This directly influenced their specific sizes, morphologies, and phases. Furthermore, these C. benghalensis-mediated nanomaterials showed high efficiency in the photocatalytic degradation of textile dyes and pharmaceuticals, as well as potential antibacterial and antioxidant properties. The Commelina benghalensis plant is flexible and renewable for efficient nanomaterial synthesis; nevertheless, issues with standardisation and scalability must be overcome to fully realise its promise for commercial and industrial uses. Full article

The synthesis of enantiomerically pure chiral β-nitroalcohols is a crucial objective in asymmetric catalysis. In order to efficiently obtain such chiral products, we developed a series of thermoresponsive, oxazoline–copper catalysts (Cu^II-PN_xFe_yO_z) via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization. These catalysts can self-assemble in water into single-chain nanoparticles (SCNPs) with biomimetic behavior, in which intramolecular hydrophobic and metal-coordination interactions generate a confined hydrophobic cavity. Comprehensive characterization by FT-IR, TEM, DLS, CD, CA, and ICP analysis confirmed the nanostructure and composition. When applied to the aqueous-phase asymmetric Henry reaction between nitromethane and 4-nitrobenzaldehyde, the optimal catalyst (2.0 mol%) achieved a quantitative yield (96%) with excellent enantioselectivity (up to 99%) within 12 h. Furthermore, the thermosensitive poly(N-isopropylacrylamide, NIPAAm) block enabled facile catalyst recovery through temperature-induced precipitation above its lower critical solution temperature (LCST). This work presents an efficient and recyclable biomimetic catalytic system, offering a novel strategy for designing sustainable chiral catalysts for green organic synthesis. Full article

This work investigates the synthesis and characterization of Barium Titanate (BT) nanoparticles, which exhibit non-linear optical properties, with a focus on their potential application in biomedical imaging. BT nanoparticles are active in second harmonic generation (SHG), enabling deep tissue imaging with a high signal-to-noise ratio. A major objective of this study is to advance in the understanding of the interactions between these nanoparticles and model biological systems. To this end, monolayers of 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC) spread on aqueous sub-phase are employed as model bio-interfaces, and the effects of BT nanoparticles on their properties are investigated using physicochemical experimental techniques such as Langmuir trough and Dynamic Light Scattering, also in the presence of albumin, a representative serum protein. The results evidence nanoparticle incorporation into the lipid layer, affecting its phase behavior, as well as the spontaneous formation of protein coronas around NPs, which is further confirmed by super-resolution optical microscopy Full article

A sustainable hybrid material, CuO/Cu₂O, was synthesized using an aqueous extract of Curcuma longa L. as a reducing and stabilizing agent. The material was characterized by UV-Vis spectroscopy, FTIR, XRD, SEM, EDX, and TEM. XRD analysis revealed peaks corresponding to CuO and Cu₂O phases with crystallite sizes of 15.88 nm and 16.71 nm, respectively. TEM images showed nearly spherical particles with some agglomeration and an average particle diameter of 8.17 nm. The hybrid material exhibited catalytic activity toward the synthesis of 1,2,3-triazoles in water, under low catalyst loading and mild reaction conditions. This work highlights the potential of Curcuma longa-mediated synthesis as a low-cost, eco-friendly alternative for producing efficient catalysts, contributing to the advancement of green chemistry and sustainable nanomaterial applications in organic synthesis. Full article

This review examines the feasibility of electrochemical synthesis of poly-L-arginine (PArg) using repetitive cyclic voltammetry in neutral aqueous phosphate-buffered saline. Previous studies on electrochemical deposition of PArg onto different carbonaceous electrode materials are discussed with respect to the already reported mechanistic models. Some controversial interpretations are of interest, predominantly the formation of peptide bonds during the electropolymerisation of L-arginine. Several alternative anodic pathways are considered via the possibilities and limitations of ways of attaching L-arginine molecules to the electrode surface. Furthermore, the role of oxygen-containing surface groups is discussed, as this aspect has been largely overlooked in the context of L-arginine deposition, despite the O-terminating character of the electrode surface and its effect on the reactivity of the nucleophilic guanidine group in L-arginine. Also, the application of extremely high potentials around +2 V vs. Ag/AgCl/3 mol L⁻¹ KCl is considered, as it can lead to the generation of reactive oxygen species that may interfere with or even govern the entire deposition process. Thus, the absence of such considerations may raise doubts about the peptide nature of the electrochemically assisted polymerisation of this basic amino acid. Finally, it seems that the identity of the electrochemically synthesised PArg does not correspond to that of this polymer prepared by conventional methods, such as solid-phase peptide synthesis, solution-phase synthesis, or N-carboxy-anhydride polymerisation, and therefore the whole process remains unproved. Full article

Curcumin is a polyphenolic compound isolated from Curcuma longa, which is widely recognized for its therapeutic properties: particularly its strong anti-inflammatory and antioxidant activities. However, its practical incorporation into functional foods, especially aqueous dairy beverages, is severely hindered by its extremely low water solubility, poor chemical stability (notably at the near-neutral pH of milk), and very limited oral bioavailability. This review provides a critical synthesis of the literature published in the last two decades, with a focus on the development and application of food-grade oil-in-water (O/W) nanoemulsions to advanced colloidal delivery systems. It covers the fundamental principles of nanoemulsion formulation, including the selection of the oil phase, surfactants, and stabilizers, as well as both high-energy and low-energy fabrication techniques. It further examines the integration of these nano-delivery systems into dairy matrices (milk, yogurt, cheese), highlighting key interactions between nanoemulsion droplets and native dairy constituents such as casein micelles and whey proteins. Critically, findings indicate that nanoencapsulation not only enhances curcumin’s solubility but also protects it from chemical degradation during industrial processes, including pasteurization and sterilization. Moreover, the dairy matrix structure plays a key role in modulating curcumin bioaccessibility, with fortified products frequently exhibiting enhanced stability, shelf life, and sensory attributes. Finally, key technological challenges addressed the heterogeneous global regulatory landscape surrounding biopolymers and future trends: most notably, the growing shift toward “clean-label” biopolymer-based delivery systems. Full article

The increasing discharge of recalcitrant organic dyes from the textile industry necessitates the development of efficient and sustainable wastewater treatment technologies. This study reports the successful eco-friendly fabrication of magnetically separable cerium–manganese ferrite (Ce-MnFe₂O₄) nanocatalysts via a one-pot green synthesis route, utilizing an aqueous extract of Brachychiton populneus leaves. The structural, morphological, magnetic, and optical properties of the synthesized nanocatalysts were systematically investigated. X-ray diffraction (XRD) analysis confirmed the formation of a phase-pure cubic spinel structure, with evidence of Ce³⁺ ion incorporation leading to lattice expansion and the formation of beneficial oxygen vacancies. The composite material exhibited superparamagnetic behavior with a high saturation magnetization of 38.7 emu/g, which facilitates efficient magnetic separation and recovery. Optical studies revealed a direct bandgap of 2.33 eV, enabling significant photocatalytic activity under visible light irradiation. The Ce-MnFe₂O₄ nanocatalyst demonstrated superior performance, achieving degradation efficiencies of 96% for methylene blue and 98% for Congo Red within 90 min. Furthermore, the catalyst demonstrated good operational stability, maintaining 62% of its initial degradation efficiency for CR and 51% for MB after five consecutive reuse cycles. These results underscore the potential of this green-synthesized, magnetically recoverable nanocatalyst as a highly effective and sustainable solution for the remediation of dye-contaminated industrial effluents. Full article

Fluoride solid solutions exhibit exceptional optical and thermodynamic properties that make them valuable for advanced technological applications, and the PbF₂-EuF₃ system represents a particularly promising quasi-binary system for developing high-performance materials. However, the comprehensive understanding of the thermodynamic conditions governing phase equilibria and the precise boundaries of homogeneity regions in this system remains incomplete, limiting the rational design of single-phase materials with desired properties. Therefore, we conducted a comprehensive investigation of the thermodynamic conditions (temperature and composition) controlling the existence of cubic and rhombohedral phases within the homogeneity regions of the PbF₂-EuF₃ system. Solid solution samples were synthesized using both solid-phase synthesis and co-precipitation techniques from aqueous nitrate solutions. Phase equilibria were systematically investigated in two critical regions: the solvus line spanning 0–10 mol% EuF₃ and the ordered rhombohedral R-phase region spanning 35–45 mol% EuF₃. Structural characterization was performed at temperatures below the phase transition temperature in lead fluoride (365 °C) using X-ray phase analysis, optical probing, and Raman scattering. Our investigation successfully demonstrated the possibility of obtaining cubic preparations of high purity across the 0–37 mol% EuF₃ composition range. Additionally, we precisely defined the region of existence of the ordered rhombohedral R-phase within the concentration range of 37–39 to 43–44 mol% EuF₃. These findings provide essential thermodynamic data for the rational design of PbF₂-EuF₃ solid solutions and establish clear compositional boundaries for obtaining desired phase structures in this technologically important fluoride system. Full article

Cerium (Ce³⁺)-doped gadolinium orthoborate (GdBO₃) phosphor powders were synthesized via an aqueous sol–gel route, with systematic variation in solution pH (2, 5, and 8) and annealing temperature (600–1200 °C, in 100 °C increments) to investigate their influence on structural, optical, and scintillation properties. The materials were comprehensively characterized using thermogravimetric and differential thermal analysis (TG–DTA) to assess thermal behavior, X-ray diffraction (XRD) for crystal structure determination, Fourier-transform infrared spectroscopy (FTIR) for vibrational analysis, and both photoluminescence (PL) and radioluminescence (RL) spectroscopies to evaluate optical and scintillation performance. All samples crystallized in the hexagonal GdBO₃ vaterite phase (space group P6₃/mcm). The PL and RL emission spectra were consistent with the Ce³⁺ 5d–4f transitions, and scintillation yields under X-ray excitation were quantified relative to a standard Gadox phosphor. A decrease in photoluminescence quantum yield (PLQY) was observed at annealing temperatures above 800 °C, which is attributed to the incorporation of Ce³⁺ into the host lattice. Scintillation decay profiles were recorded, enabling extraction of timing kinetics parameters. Overall, the results reveal clear correlations between synthesis conditions, structural evolution, and luminescence behavior, providing a rational basis for the optimization of Ce³⁺-doped GdBO₃ phosphors for scintillation applications. Full article

Mn⁴⁺-activated fluoride phosphors possess outstanding luminescent properties, making them highly suitable for applications in lighting and display technologies. However, the synthesis of such phosphors generally requires the use of large amounts of highly toxic aqueous HF, leading to serious environmental pollution. To eliminate the use of hazardous HF solution, a low-temperature molten salt method employing NH₄HF₂ was developed to synthesize the narrow-band red emitter Cs₂GeF₆: Mn⁴⁺ phosphor. Following the reaction, the product was washed with a dilute H₂O₂ solution to remove residual NH₄HF₂ and other impurities. The phase purity and morphology were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively, and the luminescence properties were examined via photoluminescence (PL) spectroscopy. The obtained phosphors exhibit bright red emission characteristics of Mn⁴⁺ under blue-violet excitation. Among them, Cs₂GeF₆: 0.08 Mn⁴⁺ shows the highest emission intensity, with an internal quantum efficiency (IQE) of 78%. A white light-emitting diode (WLED) fabricated by combining this phosphor with a blue chip and commercial Y₃Al₅O₁₂: Ce³⁺ (YAG) phosphor achieved a high luminous efficacy (LE) of ~146 lm/W, a correlated color temperature (CCT) of ~4396 K, and a color rendering index (Ra) of ~83, alongside excellent operational color stability. Full article