Search Results (4,689)

This study explored the synthesis and characterization of pectin-based composites containing encapsulated propolis and sea buckthorn oil. Both propolis and sea buckthorn oil are well known for their antioxidant and antimicrobial properties. To mitigate their sensitivity to environmental degradation, these compounds were encapsulated within a pectin matrix. The composites were prepared using an emulsification technique and subsequently for their physicochemical properties via scanning electron microscopy (SEM), ultraviolet–visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC), as well as color and mechanical testing. The results showed that freeze-dried samples exhibited heterogeneous, bubble-like structures containing nanocapsules (800–2000 nm), whereas for the film samples, the capsules were visibly embedded within the matrix. The study shows that this three-component system exhibits synergistic potential. Encapsulation significantly improved the UV barrier properties and the antioxidant activity of the nanocomposites, which demonstrated greater antioxidant capacity. Microbiological assays revealed that the pectin-based composites containing encapsulated propolis and sea buckthorn oil exhibited strong antibacterial activity, particularly against Gram-positive bacteria such as Streptococcus and Staphylococcus spp. The composites also demonstrated hydrophobic surface characteristics and reduced crystallinity, which correlates with their potential for controlled release. These results underscore the applicability of pectin–propolis–sea buckthorn oil composites as effective natural preservatives or functional ingredients in food systems, due to their high antioxidant and antimicrobial efficacy. Full article

Background/Objectives: Fenbendazole is a potential cancer treatment and a proven antiparasitic in veterinary applications. However, its poor water solubility limits its application. In this study, potential fenbendazole solubility enhancement was investigated through size reduction methods. The effect of the presence of Soluplus^® on solubility was investigated as well. Methods: Solubility enhancement was explored using microfluidization and ultrasonication techniques. These techniques were applied to fenbendazole alone and in combination with Soluplus^®. UV–Vis spectroscopy was used to determine solubility. Possible chemical reactions were checked using Fourier transform infrared spectroscopy (FT-IR). Differential scanning calorimetry (DSC) was conducted to analyze the physical structure and crystallinity of the samples. Scanning electron microscopy (SEM) was also utilized for characterization of the effect of the treated formulations and the size reduction method on morphology. The elements present in samples were identified with energy-dispersive X-ray spectroscopy (EDX) combined with SEM. A comparison of crystalline structure between the products was performed via X-ray powder diffraction (XRPD). Dynamic light scattering (DLS) was also used to measure the samples’ average particle size at different stages. Results: Both ultrasonication and microfluidization led to marginal increases in the solubility of neat fenbendazole. In contrast, formulations processed in the presence of Soluplus^® demonstrated a greater enhancement in solubility. However, solubility improvement was not retained in the dried samples. The post-drying samples, irrespective of the presence of Soluplus^®, showed nearly the same solubility as neat fenbendazole. Conclusions: Size-reduction methods, particularly when combined with Soluplus^®, improved the solubility of fenbendazole. However, drying appeared to reverse these gains, regardless of the method used. Full article

This study aimed to develop a novel biomaterial for neural tissue regeneration by combining chitosan (CS), a natural polymer, with graphene oxide (GO) at concentrations of 3%, 6%, and 9%. The homogeneity, conductivity, three-dimensional characteristics, and ability to support cell viability of the composite materials were systematically evaluated. Fourier-Transform Infrared (FTIR) spectroscopy confirmed the successful incorporation of GO into the CS matrix, while UV-Vis and photoluminescence (PL) spectrometry revealed modifications in the optical properties with increasing GO content. Thermogravimetric analysis (TG-DSC) demonstrated improved thermal stability of the composites, and swelling tests indicated enhanced water absorption capacity. Although some agglomerates were observed, the homogeneity was reasonable at both macroscopic and microscopic level (optical visualization–FTIR and electron microscopy). The composite films exhibited promising physical and electrochemical properties, highlighting their potential for neural tissue engineering applications. Their biological activity was assessed by culturing neuronal cells on the CS-GO scaffolds. Results from MTT, LDH, and LIVE/DEAD assays demonstrated excellent cell viability, moderate-to-good cell attachment, and the promotion of intercellular network formation. Among the tested formulations, the CS-GO 6% scaffold showed the most favorable biological response, with a significant increase in SH-SY5Y cell viability after 7 days (p < 0.05) compared to the CS control. LIVE/DEAD imaging confirmed enhanced cell attachment and elongated morphology, while the LDH assay indicated minimal cytotoxicity. Notably, a critical threshold was identified between 6% and 9% GO, where conductivity increased by approximately 52-fold. Future studies should focus on optimizing the composite parameters, loading them with specific biologically active agents and thus targeting specific neuronal applications. Full article

The search for bioactive compounds with antioxidant properties is critical in combating oxidative stress-related diseases and advancing novel therapeutic agents. Azo dyes, traditionally used in textiles, food, and cosmetics, have recently attracted attention due to their emerging biological activities, including antioxidant potential. In this study, we synthesized and characterized 267 azo dyes derived from natural phenolic cores such as salicylic acid, syringol, and 5,6,7,8-tetrahydro-2-naphthol. Eighteen of these compounds are novel. Structural characterization was performed using NMR, UV-Vis, IR spectroscopy, and mass spectrometry. Antioxidant activity was assessed using in vitro assays with ABTS radical scavenging method. SAR analysis revealed that dyes derived from syringol and 5, 6, 7, 8-tetrahydro-2-naphthol showed the most consistent and potent antioxidant activity. Notably, azo dyes bearing fluoro and nitro substituents in the para position exhibited the lowest IC₅₀ values, highlighting the influence of electron-withdrawing groups and substitution patterns on antioxidant behavior. This work establishes a precedent for SAR-driven evaluation of azo dyes using ABTS and supports their further exploration as functional antioxidant agents in medicinal chemistry. Full article

This work reports a low-cost, microwave-assisted wet chemistry synthesis of zinc antimonate (ZnSb₂O₆) powders with a trirutile structure, yielding highly homogeneous, nanometric particles. X-ray diffraction (XRD) confirmed the formation of the trirutile phase with lattice parameters of a = 4.664 Å and c = 9.263 Å, and an estimated crystallite size of 42 nm. UV–vis spectroscopy revealed a bandgap of 3.35 eV. Scanning electron microscopy (SEM) showed that ethylenediamine, as a chelating agent, formed porous microstructures of microrods and cuboids, ideal for enhanced gas adsorption. Brunauer–Emmett–Teller (BET) analysis revealed a specific surface area of 6 m²/g and a total pore volume of 0.0831 cm³/g, indicating a predominantly mesoporous structure. The gas sensing properties of ZnSb₂O₆ pellets were evaluated in CO and C₃H₈ atmospheres at 100, 200, and 300 °C. The material exhibited high sensitivity at 300 °C, where the maximum responses were 5.86 for CO at 300 ppm and 1.04 for C₃H₈ at 500 ppm. The enhanced sensitivity at elevated temperatures was corroborated by a corresponding decrease in electrical resistivity. Furthermore, the material demonstrated effective photocatalytic activity, achieving up to 60% degradation of methylene blue and 50% of malachite green after 300 min of UV irradiation, with the process following first-order reaction kinetics. These results highlight that ZnSb₂O₆ synthesized by this method is a promising bifunctional material for gas sensing and photocatalytic applications. Full article

The presence of secondary electromagnetic waves (EMWs) results in EMW pollution and a large need for EMW-shielding materials. Therefore, new, lightweight, flexible, chemically resistant, and durable EMW shielding materials are demanded, while graphene and its derivatives meet the above-mentioned requirements. Among graphene derivatives, N-doped graphene exhibits promising electrical properties for shielding applications, although achieving sufficient N-incorporation in the graphene sheets remains a challenge. Herein, we produced graphene oxide using the modified Hummers’ method (GO) and the electrochemical exfoliation of highly ordered pyrolytic graphite. These two GO samples were thermally treated at 500 °C and 800 °C under a pure NH₃ gas for 1 h. UV-Vis, infrared, and Raman spectroscopies and X-ray diffraction, elemental, and thermogravimetric analyses were used to investigate the structural properties of modified GO. One of the highest levels of N-doping of GO was measured (11.25 ± 0.08 at%). The modification under a NH₃ atmosphere leads to simultaneous N-doping and reduction of graphene, resulting in the formation of electrically conductive and EMW shielding materials. Density functional theory (DFT) revealed the effect of heteroatoms on the energy band gap of GO. The cluster corresponding to N-doped rGO had a reduced bandgap of 0.77 eV. Full article

This study employed a sol–gel route to fabricate mesoporous silica (MS) carriers capable of simultaneously encapsulating two widely utilized UV absorbers—benzophenone-3 (BP-3) and octyl methoxycinnamate (OMC)—resulting in the composite sunscreen agent S4M1B1. Comprehensive characterization using FTIR, TGA, UV–vis spectroscopy, DSC, SEM, and standard photoprotective indices (SPF and UVA-PF) confirmed the successful immobilization of both active ingredients within the MS porous structure, achieving a notably high loading of up to 72 wt%. Sunscreen formulations incorporating the encapsulated composite demonstrated superior photoprotective performance, exhibiting SPF and UVA-PF values approximately 40% higher than equivalent physical mixtures of the same actives. Additionally, the MS encapsulation significantly enhanced the photostability of BP-3 and OMC, effectively maintaining their UV-protective efficacy after prolonged simulated solar exposure. Franz glass diffusion cell assays further revealed that encapsulation markedly reduced the in vitro skin permeation of both BP-3 and OMC by over 55%, substantially diminishing transdermal absorption risks. The dual benefits of enhanced UV-protection efficiency and reduced dermal penetration underscore the composite’s potential as a safer and more effective active ingredient in cosmetic sunscreen products, with promising applications in advanced skincare and cosmeceutical formulations. Full article

In this study, highly ordered titanium dioxide nanotubes (TiO₂-NTs) have been synthesized using the electrochemical anodization procedure. Subsequently, the TiO₂-NTs were successfully decorated with PbS nanoparticles (NPs) using the pulsed KrF-laser deposition (PLD) technique under vacuum and under different Helium background pressures (P_He) ranging from 50 to 400 mTorr. The prepared samples (PbS-NPs/TiO₂-NTs) were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and UV–Vis and photoluminescence spectroscopies. XRD analyses confirmed that all TiO₂-NTs crystallized in the anatase phase, while the PbS-NPs crystallized in the cfc lattice. The average crystallite size of the (200) crystallites was found to increase from 21 to 33 nm when the pressure of helium (PHe) was raised from vacuum to 200 mTorr and then dropped back to ~22 nm at P_He = 400 mTorr. Interestingly, the photoluminescence intensity of the PbS-NPs/TiO₂-NTs samples was found to start diminishing for P_He ≥ 200 mTorr, indicating a lesser recombination rate of the photogenerated carriers, which also corresponded to a better photocatalytic degradation of the Amido Black (AB) dye. Indeed, the PbS-NPs/TiO₂-NTs samples processed at P_He = 200 and 300 mTorr were found to exhibit the highest photocatalytic degradation efficiency towards AB with a kinetic constant 130% higher than that of bare TiO₂-NTs. The PbS-NPs/TiO₂-NTs photocatalyst samples processed under P_He = 200 or 300 mTorr were shown to remove 98% of AB within 180 min under UV light illumination. Full article

Background/Objectives: Copovidone (polyvinylpyrrolidone-vinyl acetate copolymer, PVP/VA) is a widely used pharmaceutical excipient with various applications in drug formulation. In hot melt extrusion (HME), PVP/VA is an approved carrier material for the production of amorphous solid dispersions (ASDs) by embedding drugs on a molecular level. This study investigates the properties and processability of two copovidone grades—Plasdone™ S-630 (PS-630) and the novel Plasdone™ S-630 Ultra (PS-630U)—to assess their suitability as ASD carrier materials. Methods: The thermal and physicochemical characteristics of both polymers were evaluated, focusing on glass transition temperature and polymer melt rheology. The process performance in HME was investigated on small-scale as well as in production-scale extrusion. The two model drugs itraconazole and griseofulvin were used to examine drug dissolution and degradation during HME via in-line UV-vis spectroscopy. Results: When comparing both polymers, PS-630U offers various advantages due to the improved powder feeding behavior and reduced yellowing of extruded products while maintaining similar melt properties and drug compatibility compared to PS-630. Conclusions: These findings support the use of PS-630U as an optimized copovidone grade for ASD manufacturing, facilitating improved processing characteristics and best product qualities without the requirement of significant formulation adjustments. Full article

Background/Objectives: The rise in antibiotic resistance presents a serious and urgent global health challenge, emphasizing the need to develop new therapeutic compounds. This study focuses on the design and evaluation of a novel series of hybrid molecules that combine the 2-quinolone and 1,2,3-triazole pharmacophores, both recognized for their broad-spectrum antimicrobial properties. Methods: A library of 29 candidate molecules was first designed using in silico techniques, including QSAR modeling, ADMET prediction, molecular docking, and molecular dynamics simulations, to optimize antibacterial activity and drug-like properties. The most promising compounds were then synthesized and characterized by ¹H and ¹³C NMR APT, mass spectrometry (MS), Fourier-transform infrared (FT-IR) spectroscopy, and UV-Vis spectroscopy. Results: Antibacterial evaluation revealed potent activity against both Gram-positive and Gram-negative bacterial strains, with minimum inhibitory concentration (MIC) values ranging from 0.019 to 1.25 mg/mL. Conclusions: These findings demonstrate the strong potential of 2-quinolone–triazole hybrids as effective antibacterial agents and provide a solid foundation for the development of next-generation antibiotics to combat the growing threat of bacterial resistance. Full article

Dexamethasone (DXM) is a glucocorticoid widely used in treating various diseases, but its extensive use raises environmental concerns due to poor absorption and rapid excretion, leading to its presence in aquatic environments. In this study, aqueous DXM was treated via heterogeneous solar photocatalysis (HSP) using a Zn-doped TiO₂ catalyst supported on zeolite clinoptilolite (TiO₂-Zn(II)-ZC), synthesized by electrodeposition. The catalyst was characterized by IR spectroscopy, SEM-EDS, XRD, atomic absorption spectroscopy, and P_zc determination. A Box–Behnken design was applied to evaluate the influence of initial DXM concentration (5–15 mg/L), hydraulic retention time (HRT: 30–60 min), and catalyst dose (0.5–1.5 g/L), using DXM (UV–Vis) and COD as response variables. Optimal conditions (12.5 mg/L DXM, 60 min HRT, 1.0 g/L catalyst) achieved 80% DXM removal (UV–Vis), 88.71% (HPLC), 85.29% COD removal, and 82.86% TOC reduction at 67 °C, 325.12 kJ/L, and 38.77 W/m². Additionally, a treated sample of chocolate industry wastewater enriched with 12.5 mg/L DXM (DXM-WW) achieved 67.88% (HPLC), 93.02% (COD), and 92.38% (TOC) removal. The catalyst reduced the bandgap, enabling sunlight-driven generation of e⁻/h⁺ pairs and reactive oxygen species (^•OH, H₂O₂, and O₂^•−), facilitating DXM degradation. Full article

This study investigates the effects of different tungsten (W) doping contents on the optical transmittance, surface roughness, residual stress, and microstructure of evaporated vanadium dioxide (VO₂) thin films. W-doped VO₂ thin films with varying tungsten concentrations were fabricated using electron beam evaporation combined with ion-assisted deposition techniques, and deposited on silicon wafers and glass substrates. The optical transmittances of undoped and W-doped VO₂ thin films were measured by UV/VIS/NIR spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The root mean square surface roughness was measured using a Linnik microscopic interferometer. The residual stress in various W-doped VO₂ films was evaluated using a modified Twyman–Green interferometer. The surface morphological and structural characterization of the W-doped VO₂ thin films were performed by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). Raman spectroscopy was used to analyze the structure and vibrational modes of different W-doped VO₂ thin films. These results show that the addition of tungsten significantly alters the structural, optical, and mechanical properties of VO₂ thin films. Full article

Collagen-based biomaterials are increasingly explored in dentistry for their ability to deliver drugs locally and support healing. In this study, we developed chlortetracycline-loaded collagen sponges aimed at preventing postoperative infections. Five formulations were prepared by lyophilization, each with the same collagen-to-drug ratio but different glutaraldehyde (GA) concentrations: 0%, 0.25%, 0.5%, 0.75%, and 1% (w/w) relative to dry collagen. The sponges were characterized using FT-IR and UV–VIS–NIR spectroscopy, and their swelling capacity, enzymatic stability, and drug release kinetics were evaluated. Antibacterial activity was tested against Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. Statistical differences between formulations were assessed using one-way ANOVA followed by Tukey’s post hoc test (p < 0.05). All sponges released the antibiotic rapidly within the first 60 min, followed by a sustained release for up to 10 h. The non-crosslinked sponge showed the highest antimicrobial effect, while the 0.25% GA formulation offered a good balance between stability and bioactivity. While higher cross-linking enhanced structural stability, it progressively reduced antimicrobial efficacy, highlighting a crucial design trade-off. These findings underline the need to fine-tune cross-linking conditions to achieve both durability and strong antimicrobial action in collagen-based drug delivery systems for dental applications. Full article

One of the most sensible, economical, and ecologically friendly methods for treating wastewater is photocatalytic treatment. The most widely used and easily accessible photocatalyst for wastewater treatment is zinc oxide (ZnO). This study used laser ablation to create ZnO, Mo, and Mo-doped ZnO photocatalysts. The nanoparticles were then characterized using linear absorbance, X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The degradation of methylene blue under UV-Vis spectroscopy was used to evaluate the photocatalytic activity of the photocatalysts and the reaction’s kinetics. The Mo doping of ZnO enhanced photocatalytic degradation efficiency, according to the analytical data. This study’s 90 min photocatalytic degradation experiments showed about 94.11% methylene blue degradation efficiency. Mo-doped ZnO nanoparticle photocatalysts have a promising future for treating wastewater, according to this study, which calls for more research in this area. Full article

This study investigates the synthesis and characterization of boron-modified nanotubular titania (NTO) arrays fabricated via a single-step anodizing process with varying concentrations of boric acid (BA). Following anodization, a reductive heat treatment was applied to facilitate the crystallization of the anatase phase in the boron-modified NTO. The effect of the BA concentration on the structural, morphological, and photoelectrochemical (PEC) properties of the NTOs was systematically explored through scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), luminescence, and UV-Vis spectrometry. The introduction of boron during anodization facilitated the formation of sub-bandgap states, thereby enhancing the light absorption and electron mobility. This study revealed the optimal BA concentration that yielded a 3.3-fold enhancement of the PEC performance, attributed to a reduction in the bandgap energy. Notably, the highest incident photon-to-current conversion efficiency (IPCE) was observed for NTO samples anodized at a 0.10 M BA concentration. These findings underscore the promise of boron-modified NTOs for advanced photocatalytic applications, particularly in solar-driven water-splitting processes. Full article