Search Results (3,964)

Nanocomposite materials combine diverse material properties to form multifunctional structures, enhancing the efficiency of conventional applications. Particularly in environmental monitoring, such as water analysis, nanocomposites significantly improve sensitivity and lower costs associated with standard analysis methods. The SERS method is gaining popularity due to its operational simplicity, on-site applicability, and rapid results delivery. This study focused on the development of a multifunctional metal-chitosan-based nanocomposite utilizing an economical, eco-friendly approach as an SERS substrate. The resulting composite exhibits considerable preconcentration capabilities and will provide low detection limits (LOD) for future SERS applications. Specifically, magnetic nanoparticles (MNPs) were electrostatically combined with chitosan-coated silver nanoparticles (Chi-Ag NPs) to synthesize the MNPs@Chi-Ag NPs nanocomposite. CoFe₂O₄ NPs were prepared as MNPs. The resulting nanocomposite, which demonstrated colloidal stability after optimization, was characterized using various techniques, including UV-VIS and FTIR spectroscopy, XRD, TEM, SEM, and DLS. As a SERS substrate, the MNP@Chi-Ag NPs exhibited considerable analytical enhancement factors of (1.5 ± 0.4) × 10⁶, (7.0 ± 0.3) × 10⁶, and (1.2 ± 0.5) × 10⁶ for the detection of water contaminants BCB, CV, and MP, respectively. It was demonstrated that the substrate enhances precision and exhibits preconcentration. Finally, the MNPs@Chi-Ag NP nanocomposite demonstrates remarkable antibacterial activity, with larger inhibition zones observed at higher nanocomposite concentrations, indicating a concentration-dependent effect. Full article

(1) The growing interest in the use of natural and sustainable ingredients highlights the investigation of vegetable oils in dermato-cosmetic applications. In this context, the vegetable oil obtained from walnut (Juglans regia L.) is of actual interest due to its composition rich in unsaturated fatty acids. The aim of the present study was to investigate and characterize walnut oil from a physicochemical, structural, and rheological point of view. (2) The oil was obtained by a cold pressing process from walnut seeds, with a yield of about 51.03 ± 1.41%, and subsequently analyzed by complementary methods. (3) The results show an acceptable physicochemical profile, characterized by appropriate values of density, pH, and spreadability. The oxidative stability indicated a moderate resistance to degradation, specific to oils rich in polyunsaturated fatty acids. Fourier infrared transform spectrometry (FTIR) analysis confirmed the presence of functional groups characteristic of triglycerides, without indications of advanced oxidation, and atomic force microscopy (AFM) investigations revealed a heterogeneous morphology. The rheological properties indicated a pseudoplastic behavior, favorable for topical application. The determination of heavy metals confirmed the safety of the raw material for the intended dermato-cosmetic use. While arsenic levels were slightly above the strict Codex Alimentarius limits for foodstuffs, all values remained within the safety ranges established for cosmetic ingredients. A total of six fatty acids were found in cold-pressed walnut oil, determined using GC-MS methods. The number of compounds identified in the silylated sample was found to be 17. The antioxidant activity determined using DPPH and ABTS methods was generally considered good and relatively stable over time. The measured sun protection value (SPF) demonstrates a favorable capacity to act as a photoprotective ingredient against ultraviolet (UV) radiation. (4) Overall, the results demonstrate that walnut oil presents adequate physicochemical and structural properties, supporting its further use as a potential cosmetic raw material. Full article

This study developed high-performance, biodegradable nanocomposites from polyvinyl alcohol (PVA) reinforced with nanocellulose derived from the invasive Nile rose plant (NR). Cellulose nanofibrils (CNFs) were successfully extracted using maleic anhydride treatment, yielding nanofibers with an average diameter of 20.81 nm and a high negative surface charge of −40.7 mV, indicating effective functionalization. The synergistic effect of incorporating 7.5% CNF and applying 50 kGy gamma irradiation dramatically enhanced the composite properties, resulting in a 64.01% improvement in tensile strength compared to neat PVA. The crosslinked network significantly increased hydrophobicity, with the water contact angle rising from 60.95° to 106.40°, and reduced moisture absorption. Optical characterization demonstrated excellent UV-shielding capabilities, maintaining a visible light transmittance of 66.6% at 800 nm, while thermal analysis confirmed enhanced stability against high-temperature degradation. These findings suggest that the developed nanocomposites are promising candidates for advanced protective packaging applications where UV shielding and moisture resistance are critical. Full article

Background/Objectives: Gold(I) complexes are promising bioactive agents with anticancer and anti-inflammatory potential. This study evaluated cytochrome P450 (CYP) interactions and in vitro pharmacokinetic properties of two Au(I)–triphenylphosphine complexes bearing 6-alkoxy-9-deazapurine ligands. Methods: Complexes [Au(HL_1,2)(PPh₃)] (HL₁ = 6-isopropyloxy-9-deazapurine, complex 1; HL₂ = 6-benzyloxy-9-deazapurine, complex 2) were investigated. Inhibition of nine human CYP isoforms was assessed in liver microsomes, and kinetics were analyzed using Dixon and Lineweaver–Burk plots. CYP binding was evaluated by UV–Vis difference spectroscopy. ADME properties (chemical/plasma stability, microsomal stability, plasma protein binding, and PAMPA permeability) were determined. Binding thermodynamics were analyzed by ITC. Results: Both complexes weakly inhibited most CYP isoforms, with stronger effects on CYP2C9 and CYP3A4/5. A non-competitive inhibition mechanism was observed, which may be related to the binding of the complexes to the substrate channels of CYP2C9 and CYP3A4, thereby limiting the active site’s accessibility to the substrate, as supported by molecular docking studies. UV–Vis spectra showed type I binding with Kd values of 9.32 µM (1) and 12.64 µM (2). Both compounds showed high chemical and plasma stability (>90%), moderate microsomal stability (~60% after 60 min), high plasma protein binding (~80%), and low passive permeability. Conclusions: Au(I)–triphenylphosphine complexes with 6-alkoxy-9-deazapurine ligands exhibit moderate CYP affinity and defined pharmacokinetic profiles, supporting further preclinical evaluation. Full article

Surface-enhanced Raman scattering (SERS) offers exceptional sensitivity for trace contaminant detection; conventional noble-metal substrates suffer from high cost, signal irreproducibility, and poor chemical stability. While semiconductor alternatives are promising, their performance is fundamentally limited by sluggish interfacial charge-transfer kinetics under static band alignment. To overcome these limitations, we introduced a new strategy centred on a high carrier generation rate (HCGR). By integrating TiOPc, a material that exhibits strong Ti–O bond polarisation and a high HCGR, with atomically thin MoS₂, we constructed a hybrid platform that drives efficient charge transfer via HCGR-enabled kinetic pumping, surpassing traditional thermodynamic band engineering. This HCGR-driven efficient CT mechanism primarily amplifies SERS through enhanced chemical mechanisms (CM) with minor electromagnetic contributions, achieving an enhancement factor (EF) of 10⁷. The platform can detect methylene blue (MB) and rhodamine 6G (R6G) at concentrations as low as 10⁻¹⁴ M and 10⁻¹³ M, respectively, demonstrating excellent repeatability (RSD = 7.2%) and stability over 60 days. Additionally, efficient CT accelerated MB photodegradation under UV light, achieving complete decomposition within 80 min. The practical applicability of the platform is evidenced by detecting Hg²⁺ (LOD: 10⁻¹¹ M) and malachite green in tap/lake water (LODs: 10⁻¹² M/10⁻¹⁰ M). This work establishes HCGR-driven efficient CT as the next generation of semiconductor SERS platforms. It provides a scalable route toward low-cost, reusable sensors for real-time, in situ monitoring of industrial effluents and the dynamic pollutant degradation of pollutants in environmental monitoring. Full article

Ammonia (NH₃) emissions from livestock facilities pose significant environmental challenges, particularly under high-humidity conditions where conventional adsorption efficiency significantly declines. This study investigates the photocatalytic removal of NH₃ using TiO₂-coated zeolite LTA supports (3A and 4A) under relative humidity (RH) levels typical of farm environments. The composites were synthesized via controlled dip-coating cycles and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Brunauer–Emmett–Teller (BET) analyses. At 55% RH, zeolite 3A exhibited higher NH₃ removal efficiency than zeolite 4A, owing to its smaller pore size and superior intrinsic adsorption selectivity. However, adsorption-only systems underwent rapid deactivation over repeated cycles. While TiO₂ coatings enhanced the photocatalytic activity of both supports, zeolite 3A composites showed a more pronounced decline in efficiency over time. In contrast, at 95% RH, the TiO₂-coated zeolite 4A achieved superior photocatalytic efficiency and operational stability. This performance is attributed to the 4A framework’s greater water uptake and faster diffusion kinetics, which promoted the generation of hydroxyl (•OH) and hydroperoxyl (HO₂•) radicals under UV-A irradiation. These findings suggest that while TiO₂–zeolite 3A is effective at moderate humidity, TiO₂–zeolite 4A is more robust for high-humidity livestock environments, providing a sustainable strategy for effective NH₃ emission control. Full article

The temperature-sensitive plugging agent (HAAN) was synthesized via free-radical graft polymerization using hydroxypropyl methyl cellulose (HPMC), acrylamide (AM), 4-acryloylmorpholine (ACMO) and N-vinyl-2-pyrrolidone (NVP) as the main monomers. HAAN demonstrates potential for addressing the frequent lost circulation problems encountered during the drilling of complex formations. The target product was characterized by FTIR and ¹H NMR. Its phase transition behavior was verified via temperature-dependent UV-visible transmittance measurements and high-temperature rheological tests. The experimental results show that the plugging agent possesses good temperature and salt tolerance, and its rheological properties can be enhanced by incorporation into drilling fluid. It demonstrates effective plugging performance both at room temperature and under high-temperature conditions, thereby contributing to improved wellbore stability. It provides a new idea for green multifunctional application of cellulose in water-based drilling fluid. Full article

In the present study, innovative active gelatin–chitosan films enriched with blackberry (ACTIVE-BF) and sage flower (ACTIVE-SF) extracts were developed and comprehensively characterised with regard to their physicochemical, functional and environmental properties. The incorporation of phenolic compounds increased the film’s UV–Vis (ultraviolet–visible spectroscopy) absorbance, confirming the presence of chromophoric groups and the improvement of light-barrier properties. FTIR (Fourier Transform Infrared Spectroscopy) analysis revealed hydrogen bond formation and intermolecular interactions between polyphenols and the –OH/–NH groups of the biopolymer matrix, which enhanced the structural stability of the films. Adding blackberry and sage extracts slightly increased the hydrophilicity and solubility of the films (40–48%), without significantly affecting their water vapour transmission rate (531–547 g/m²·d). The obtained films exhibited strong antioxidant activity, with FRAP (Ferric Reducing Antioxidant Power) values ranging from 17.75 to 40.83 mM Trolox/mg, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging capacity between 42.58 and 46.88%, and metal chelating ability up to 50.82%. During the nine-day storage of salmon fillets at 4 °C, the active films effectively inhibited microbial growth (reduction of 1.5–2.1 log CFU/g) while maintaining pH stability (6.2–6.4). Respiration activity confirmed environmental safety. The developed materials represent biodegradable, multifunctional films with high potential for application as sustainable active packaging for perishable food products. Full article

To compare the structure and properties of hydroxypropyl starch/carrageenan blends with different amylose/amylopectin contents, two types of hydroxypropyl starch—a high-amylose type (amylose content > 70%) and a high-amylopectin type (amylopectin content > 95%)—were used. These starches had similar molecular weights, degrees of hydroxypropyl substitution, and other properties, differing only in their amylose and amylopectin contents. Each starch was blended with carrageenan via a solution blending method, and the resulting blends were systematically characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis, rheological tests, texture analysis, mechanical property tests, contact angle analysis, and UV-Vis spectrophotometry. The results showed that, upon blending with carrageenan, the hydroxypropyl starch transformed from a weak viscoelastic solution into an elastic, strong gel. FTIR and XRD analyses confirmed that the hydroxypropyl starch and carrageenan formed a homogeneous, compact, three-dimensional network via hydrogen bonding. This significantly enhanced the mechanical strength and stability of the blends. The influence of starch molecular structure on the blend system’s properties exhibited a pronounced state dependence. In the gel state, hydroxypropyl amylopectin effectively filled the carrageenan network due to its high swelling capacity, thereby improving the thermal stability and textural properties of the blends. However, in the film state, hydroxypropyl amylose with higher crystallinity and denser molecular packing contributed to superior tensile strength, hydrophobicity and light transmittance. Furthermore, the optimal mass ratio of hydroxypropyl starch to carrageenan was found to be in the range of 2:1 to 4:1. With this ratio, excessive cross-linking and poor compatibility could be avoided, resulting in improved mechanical performance, hydrophobicity, and light transmittance. This study reveals the relationship between starch molecular structure, system state and macroscopic properties, providing a theoretical basis for the rational design and regulation of the properties of hydroxypropyl starch/carrageenan blends. Full article

In this work, an in situ UV-assisted photoreduction was used to functionalize silk fibroin films with silver nanoparticles in order to develop antibacterial devices for wound healing applications. The process showed high efficiency (~80%) in terms of reacted silver precursor. The effects of the silver treatment on fibroin macromolecule were evaluated in function of the process parameters in terms of chemical structure, thermal and mechanical properties, swelling behavior, resistance to degradation and antibacterial activity. Silver functionalization significantly improved the mechanical properties of the films, with Young’s modulus increasing from 0.23 ± 0.04 MPa (methanol-treated samples) to 7.26 ± 0.46 MPa (silver-functionalized samples). In parallel, a marked reduction in swelling degree was observed (from ~360–420% to ~60%), indicating enhanced structural stability. The treated films also exhibited improved resistance to degradation over 7 days under physiological conditions. From a functional perspective, the materials showed strong antibacterial activity, with up to 97–98% reduction in bacterial proliferation for Pseudomonas aeruginosa and Escherichia coli, and up to 93% for methicillin-resistant Staphylococcus aureus. Overall, the results demonstrate that silver functionalization process improves the structural stability of silk fibroin while conferring sustained antibacterial activity, thus supporting their potential application as antimicrobial dressings for the treatment of superficial and low-exudate wounds. Full article

Halloysite nanotubes (HNTs), composed of an aluminosilicate framework, are naturally abundant, biocompatible, and sustainable clay minerals with a tubular morphology and tunable surface chemistry, making them attractive platforms for targeted, multifunctional drug delivery systems. In this study, a zinc ferrite integrated halloysite nanocomposite (ZnFe₂O₄/HNT) was developed via a one-pot synthesis approach for sustained release of cisplatin (Cp), aiming to reduce systemic toxicity and enhance cell-specific activity. The nanocomposites were further functionalized by integrating Cp (Cp: ZnFe₂O₄/HNT ratio 0.05) and folic acid (ZnFe₂O₄/HNT/Cp: FA ratio 0.05), followed by PEGylation (0.17 µL/mg of ZnFe₂O₄/HNT/Cp/FA/PEG). The structural and surface characteristics, phase, interfacial interactions (FA and Cp), and colloidal stability of nanoformulations were systematically investigated using powder X-ray diffraction analysis (XRD), Fourier transformed infrared (FT-IR) spectroscopy, zeta potential analysis, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), high-resolution transmission electron microscopy (HRTEM), and diffuse reflectance UV–visible (DRS-UV-Vis) spectroscopy. The results confirmed that ZnFe₂O₄ integration preserved the clay’s tubular framework while inducing nanocrystallization of both ferrite and cisplatin, indicating molecular dispersion within the clay matrix. Functionalization with FA (ZnFe₂O₄/HNT/Cp/FA) promoted amide bond linkage, modulated Cp-FA interactions, and significantly enhanced cumulative Cp release compared to the non-functionalized system ZnFe₂O₄/HNT/Cp (10.3% at 72 h vs. 34.4% at 72 h) under tumor acidic conditions (pH 6.6). PEGylation maintained the controlled release profile while improving dispersion stability. In vitro cytotoxicity studies revealed that FA-conjugated nanocomposites exhibited enhanced, time-dependent anticancer activity against HeLa cervical cancer cells, with reduced toxicity toward normal fibroblasts, indicating preferential cellular uptake via folate receptor-mediated mechanism. Overall, this work demonstrates that FA-functionalized ZnFe₂O₄/HNT nanocomposite provides an effective clay-based platform for modulating Cp release and enhancing folate receptor protein-mediated targeted therapy for cervical cancer. Full article

The objective of this study was to evaluate colour changes in cotton fibres within knitted fabric structures under different light exposure conditions and to assess the applicability of forensic analytical methods for this purpose. Fabrics of three distinct colours were exposed to two types of irradiation: natural sunlight and artificial light in a controlled climatic chamber. A multi-scale analytical approach was applied, including visual inspection and stereomicroscopy for macro-level evaluation, followed by bright-field microscopy, fluorescence microscopy, and UV–Vis microspectrophotometry for single-fibre characterisation. Visual assessment of fabrics revealed perceptible colour differences between exposed and unexposed samples, whereas stereomicroscopy did not consistently enhance the detection of these alterations. Bright-field and fluorescence microscopy showed no visually perceptible differences between fibres from exposed and unexposed fabrics of the same colour. Microspectrophotometric measurements did not reliably capture colour changes in single cotton fibres, particularly in samples exposed to natural sunlight. Furthermore, total colour difference (ΔE) values, ranging from 0.248 to 6.652, were found to be unreliable at the single-fibre level due to significant spatial variability across different measurement sites. The findings indicate that, while light exposure may induce perceptible colour alterations in cotton knitted fabrics, the forensic examination of single fibres does not necessarily reflect these macro-scale changes. From a forensic perspective, the stability of microscopic and microspectrophotometric characteristics supports reliable fibre comparison, even after post-event exposure to sunlight. Full article

To reveal the long-term anti-aging mechanisms of rubber–plastic elastomer-modified asphalt in complex service environments and overcome the inherent defects of single polymer modifiers—namely their susceptibility to degradation or phase separation—this study prepared styrene-butadiene-styrene (SBS), low Mooney rubber (LMMR), and low-density polyethylene (LDPE)-modified asphalts. Simultaneously, an LMMR-LDPE rubber–plastic thermoplastic elastomer (TPE) was fabricated utilizing twin-screw extrusion technology and subsequently used to prepare a composite-modified asphalt. Three aging protocols were simulated: short-term thermo-oxidative aging (RTFOT), long-term pressure aging (PAV), and ultraviolet light aging (UV). A multi-scale quantitative characterization was conducted using a dynamic shear rheometer, Fourier transform infrared spectroscopy, and atomic force microscopy to evaluate the rutting factor, carbonyl index, and surface microroughness of each system before and after aging. The experimental results indicate that the coupled effect of long-term stress and thermal oxidation causes the most severe damage to the colloidal structure of modified asphalt. Conventional SBS-modified asphalt, due to its abundance of unsaturated double bonds, exhibits a sharp increase in the carbonyl index and aging index of the rutting factor after aging, making it highly susceptible to oxidative chain scission. Although LDPE-modified asphalt possesses chemical inertness, it is prone to crystalline phase separation under aging conditions, resulting in a microroughness distortion rate of up to 86.36%. In contrast, the LMMR-LDPE composite system, leveraging the high chemical stability of the saturated aliphatic carbon chain and the flexibility-enhancing and crystallization-inhibiting effects of LMMR, effectively reduces active oxidation sites and improves interfacial compatibility. This composite system exhibits the lowest carbonyl increment and rheological attenuation under all aging conditions, while effectively inhibiting the free migration and agglomeration of macromolecular components. The LMMR-LDPE composite modification technology effectively overcomes the inherent drawbacks of single polymers, such as susceptibility to degradation or segregation, demonstrating excellent long-term macroscopic rheological stability and microscopic phase morphology anti-aging capability. The present findings provide laboratory-scale mechanistic support for the design of durable rubber–plastic-modified asphalt systems, while further pilot-scale, economic, and field validation is still required before practical engineering application can be fully assessed. Full article

Zirconium oxide nanoparticles (ZrO₂ NPs) were synthesized via a plant-assisted route using Cycas revoluta leaf extract as a natural reducing and stabilizing agent. The synthesis and properties of the NPs were confirmed using UV–Vis, FTIR, XRD, SEM-EDS, HR-TEM/SAED, DLS, and zeta potential measurements. The adsorption performance of ZrO₂ NPs toward doxycycline from water was investigated by varying pH, adsorbent dose, initial concentration, temperature, and contact time. Under the optimum conditions (pH 7, 50 mg adsorbent in 50 mL, 10 mg L⁻¹ doxycycline, 60 °C, 180 min), a maximum removal efficiency of 60.81% was achieved. The equilibrium data were fitted using the Langmuir model, giving an estimated qmax of 11.276 mg g⁻¹; however, this value should be interpreted cautiously because of the limited number of isotherm data points. The time-dependent adsorption data were empirically described using both pseudo-first-order and pseudo-second-order kinetic models without assigning strict superiority to either model. These results indicate that green-synthesized ZrO₂ NPs can serve as a low-impact adsorbent for removal of pharmaceutical contaminants in water. Full article

The growing demand for sustainable solutions in civil construction has driven the use of industrial waste in the formulation of new materials. This study evaluated the alterability of artificial stone slabs produced with 87% ornamental stone waste (Dumont Quartzite and Preto São Gabriel Granite) and 13% epoxy matrix, using the vacuum vibro-thermo-compression technique. Alterability was tested against staining agents, chemical attack, wetting and drying cycles, UV radiation, salt crystallization, three-point flexural strength test after freeze–thaw cycles, and natural weathering. Quantitative results revealed high physical stability, with mass loss varying only between 0.11% and 0.23% in wetting and drying cycles. In salt crystallization, mass loss ranged from 0.38% to 0.47%, lower than the rates of 0.87% and 1.36% reported in the literature for similar materials. Regarding mechanical performance, freeze–thaw cycles caused reductions in flexural strength between 11.66% and 31.59%; however, the stones maintained final strength values above 20 MPa, classifying them as very high-strength materials. The results indicated good physical and chemical stability of the materials, with low mass loss and preservation of mechanical properties, except under UV radiation and natural weathering, which caused significant chromatic alterations. The data obtained demonstrate the viability of applying these stones in indoor environments, promoting the valorization of waste and contributing to the circular economy. Full article