Search Results (25,473)

In this work, three functionalized hybrid composites, CS/PVA-VAN, CS/PVA-VAN@TiO₂ and CS/GO/PVA-VAN@TiO₂, were synthesized and applied for adsorption evaluation on two common non-steroidal anti-inflammatory drugs, i.e., diclofenac (DCF) and ketoprofen (KTP). The structural and morphological characteristics of new composites were identified via Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and BET techniques. BET analysis demonstrated that the CS/GO/PVA-Van@TiO₂ composite has a surface area 64.86 m²/g, which is twice that of CS/PVA-Van. Moreover, adsorption evaluation was achieved at an optimum pH condition (pH 5.0) for both drugs. In addition, the kinetic data fitted better in a pseudo-second-order kinetic model, while the adsorption was heterogeneous and multilayer. The adsorption capacity of CS/GO/PVA-VAN@TiO₂ was found to be 114.53 mg/g and 65.20 mg/g for diclofenac and ketoprofen, respectively. Thermodynamic analysis confirmed that the adsorption process was endothermic and spontaneous for all pollutants. Moreover, the kinetic swelling and stability studies demonstrated that graphene oxide contributed to improving the structural compactness and stability of composite. Finally, the adsorption performance of the optimal composite material was investigated in a binary system of non-steroidal anti-inflammatory drugs in various ratios. Full article

Expanded polystyrene (EPS) waste poses a major environmental concern due to its high volume, low density, and resistance to biodegradation. In this study, post-consumer EPS was reprocessed into continuous microfibers by Air Jet Spinning (AJS) using chloroform and chloroform/D-limonene as solvent systems. The effects of polymer concentration, air pressure, and solvent ratio on fiber formation were systematically investigated through rheological and surface tension analyses. The incorporation of 10 vol. % D-limonene improved jet stability and reduced bead formation, attributed to its lower volatility and favorable solubility with EPS, as supported by Hansen solubility parameters. SEM analysis confirmed uniform microfiber formation within a defined processing window. FTIR spectra indicated preservation of the polystyrene chemical structure, while TGA and DSC analyses were used to evaluate thermal behavior and assess potential residual solvent retention, particularly related to D-limonene. The results elucidate the interplay between solvent volatility, solution properties, and fiber morphology, establishing a sustainable processing framework for converting EPS waste into value-added fibrous materials via AJS. This work contributes to the United National Sustainable Development Goals, particularly SDG 12 (Responsible Consumption and Production) by promoting EPS waste valorization, and SDG 13 (Climate Action) through the partial replacement of conventional solvents with sustainable alternative. Full article

The study presents novel photocrosslinked hydrogels based on methacrylated chitosan and methacrylated gelatin/allyl-modified gelatin and compares their properties as drug delivery systems in wound healing applications. The polymers were selected due to their biocompatible, mucoadhesive, cell-interactive properties and flexibility in adjusting their structure, making them suitable candidates for applications that require tissue repair. A range of hydrogel formulations was obtained by modulating the ratio of modified chitosan to two distinct modified gelatins, with photocrosslinking performed using Irgacure 2959 as the photoinitiator. FT-IR analysis, SEM data, and swelling and mechanical properties confirmed the 3D networking and the compatibility between the hydrogel components. Allylic gelatin-based hydrogels present larger pores and a stronger pH-responsive swelling behaviour compared to methacrylated gelatin-based samples, reflecting the higher flexibility of allylic gelatin networks. The hydrogels release bacitracin during the first six hours, with a release profile that follows a non-Fickian diffusion mechanism. Cytocompatibility and wound healing potential were tested in the presence of human and mouse fibroblasts, cells with a pivotal role in the wound healing process. All formulated hydrogels exhibit antioxidant capacity and protein stabilization properties, which are attributed to the presence of chitosan in their composition. The cytocompatibility, in vitro wound healing, and biological properties of the obtained hydrogels, as well as the drug release results, confirm their suitability in wound healing applications. Full article

Eutectic solvents have become a viable choice to create innovative pharmaceutical technologies within the framework of the green chemistry approach. Despite the growing applicative interest, a general gap remains in the pharmaceutical sector regarding thorough and systematic research of their properties and useful applications. In this work, eutectic solvents have been prepared from choline chloride and polyols (sorbitol, xylitol, mannitol, and isomalt) at different molar ratios (1:1, 2:3, and 3:2), characterised, and used for the solubility enhancement of poorly water-soluble drugs (ibuprofen and naproxen) as well as the potential drug candidate apigenin. The interactions between the eutectic solvent components were investigated by DSC, FTIR, and refractive index methods. In all eutectic solvents, the water content detected by Karl Fischer titration and loss on drying was less than 3%. Solubility studies, carried out using the shake-flask method, showed significant solubility enhancement of the following: ibuprofen: ~152-fold increase, naproxen: ~144-fold increase, and apigenin: ~188-fold increase. These findings highlighted the great potential of eutectic solvents as solubility enhancers in the development of novel and more effective drug delivery systems. Full article

Zirconia-based hybrid blends at various molecular or nanometer scales have attracted significant interest from a technological perspective. In particular, several inorganic-organic hybrids are being applied in the biomedical field. In this context, inorganic ZrO₂ and hybrids composed of ZrO₂, and polyethylene glycol (PEG) have been synthesized through the sol–gel process and characterized from both morphological and spectroscopic viewpoints to explore their potential as hybrid biomaterials. Atomic Force Microscopy (AFM) has enabled a quantitative assessment of the surface roughness of bioactive sol–gel-based materials. The findings indicated an increase in material porosity in relation to the amount of PEG present in the systems, underscoring the important role of PEG in influencing the morphological characteristics of zirconia-based blends. AFM images display the typical globular structure of PEG spread across the surface of all systems. All hybrid systems seem to be uniform, and no phase separation is evident, thereby validating that the produced materials are hybrid nanostructured ones. The simultaneous presence of both inorganic and organic phases was verified using Fourier-transform infrared spectroscopy (FT-IR). FT-IR deconvolution in 850–550 cm⁻¹ region showed that PEG progressively perturbs the Zr–O–Zr network, increasing disorder and establishing more flexible inorganic domains at high PEG content. Increasing polymer amount enhanced cell viability against NIH-3T3 cell line, while antibacterial activity decreased, with pure ZrO₂ showing the strongest inhibition against Escherichia coli (E. coli). Full article

The synergistic effects of glucose (Glu) concentration and clay mineral type (kaolinite [Kao], montmorillonite [Mon]) on abiotic humification via the polyphenol-Maillard reaction remain poorly understood. To address these scientific challenges, a series of controlled, sterile batch experiments was conducted. Specifically, a glucose concentration gradient (0, 0.03, 0.06, 0.12, and 0.24 mol/L) was established; Kao and Mon were separately introduced as mineral catalysts; and the Maillard reaction was facilitated in the presence of catechol and glycine under strictly abiotic conditions to preclude any potential biological interference. Comprehensive analyses were performed on the reaction products—namely, the supernatant and the dark-brown residue generated during the reaction process. These analyses included: the E₄/E₆ ratio and total organic carbon (TOC) content of the supernatant; the carbon-based ratio of humic-like acid to fulvic-like acid (C_HLA/C_FLA); and the structural characteristics of humic-like acid (HLA) isolated from the dark-brown residue. Results showed dynamic E₄/E₆ ratio and TOC changes in the supernatant were accurately described by the Logistic function. Kao favored soluble organic C accumulation and enhanced retention of early-stage, low-molecular-weight intermediates in the dark-brown residue, while Mon promoted humic-like substances (HLS) polymerization and aromatic condensation. FTIR spectroscopy analysis identified optimal Glu thresholds for maximal HLS formation—0.03 mol/L for Kao and 0.06 mol/L for Mon—indicating non-linear, rather than monotonic, dependence on Glu dosage. Comparative pre- and post-reaction Fourier-transform infrared (FTIR) spectroscopy further demonstrated that Mon, owing to Mg–OH octahedral sites arising from isomorphic substitution, formed more stable Cat chelates than Kao. These chelates effectively stabilized surface-bound hydroxyl-associated water molecules and modulated the electron cloud distribution around Si–O bonds. Collectively, this study clarified the dual regulatory role of Glu concentration and clay mineral identity in abiotic humification pathways, advanced mechanistic understanding of clay mineral-mediated polyphenol-Maillard reactions, and established a scientific foundation for optimizing humification efficiency in both engineered and natural systems. Full article

We investigate 3D-printed composite materials composed of a photosensitive polylactic acid (PLA) resin blended with 10% starch and fabricated by Digital Light Processing. We synthesize the 3D-printed composites by incorporating a post-processing stage involving thermomoulding at various temperatures ranging from 50 °C to 150 °C. The composition, structure, and thermal and mechanical performance of the 3D-printed composites are evaluated using infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), synchrotron X-ray microtomography and tensile testing assisted with digital image correlation. Our results indicate that post-treatment influences the mechanical behaviour of the composites, leading to a moderate increase in stiffness while the tensile strength remains slightly reduced compared with the reference condition, particularly when moulding temperatures reach 100 °C. Our 3D printing approach combined with the photosensitive/starch blend provides a cost-effective alternative for obtaining 3D-printed biosourced components, maintaining technical performance at a reasonable cost. Full article

Silver nanoparticles synthesized using natural polysaccharides have received attention for their biocompatibility and potential selective anticancer activity. In this study, the physicochemical properties and biological activity of silver nanoparticles prepared using gums from Acacia senegal (ASS) and Acacia seyal (ASY) were compared. The gums were analyzed to determine their physicochemical characteristics and used as natural reducing and stabilizing agents in nanoparticle synthesis. The resulting nanoparticles were characterized using UV–visible spectroscopy, FTIR, dynamic light scattering, and zeta potential analysis. Their cytotoxicity was evaluated in MCF-7 breast cancer cells and HEK-293 normal cells using MTT assay, flow cytometry, and intracellular reactive oxygen species (ROS) measurement. Both gums showed properties consistent with Gum Arabic, with a higher protein content in ASS. ASS-derived nanoparticles were smaller and had greater colloidal stability. Both formulations reduced MCF-7 cell viability in a dose-dependent manner, with lower IC₅₀ values observed for the ASS-based nanoparticles. Apoptosis induction was associated with increased ROS generation. Limited cytotoxicity toward HEK-293 cells resulted in favorable selectivity indices. Acacia gum–mediated silver nanoparticles demonstrate selective anticancer activity, and gum composition significantly influences nanoparticle stability and bioactivity, supporting their potential application in breast cancer nanotherapy. Full article

Hybrid nanomaterials integrating magnetic and semiconductor phases offer promising multifunctional platforms for wastewater remediation; however, their stabilization and recovery remain challenging. In this study, Fe₃O₄ and ZnTiO₃/TiO₂ nanoparticles were incorporated into a rice husk ash-based geopolymer matrix to develop hybrid nanocomposites for synergistic adsorption–photodegradation of methylene blue (MB) and methyl orange (MO). The materials were synthesized via alkaline activation followed by nanoparticle incorporation, and characterized by XRD, XRF, FTIR, SEM, EDX, BET surface area analysis, and pHPZC determination. XRD confirmed the presence of nanocrystalline Fe₃O₄ and ZnTiO₃/TiO₂ phases while preserving the amorphous aluminosilicate framework. Modified powders exhibited higher specific surface areas (up to 198 m² g⁻¹) compared to the unmodified geopolymer. Adsorption followed the Langmuir isotherm and pseudo-second-order kinetics, with spontaneous and exothermic behavior. Under UV irradiation, the ZnTiO₃/TiO₂-modified composite achieved photodegradation efficiencies up to 94% for MB and 92% for MO, whereas the Fe₃O₄-modified material combined adsorption capacity with magnetic recoverability. These results demonstrate that nanoparticle incorporation enables multifunctional performance while maintaining structural integrity of the geopolymeric matrix. Full article

This study investigates the formation mechanism of lactic-acid-derived coatings produced by open-air atmospheric-pressure plasma polymerization. A comparison of nebulization and bubbling precursor-delivery methods using FT-IR and XPS showed that the bubbling method facilitated plasma-assisted chemical bonding, including the possible formation of copper(II) lactate-like interfacial species and the retention of carbonyl-containing functional groups. However, the present dataset does not provide direct, discriminating evidence for a specific metal-lactate interfacial species, and alternative interpretations such as adsorption, oxidation, hydroxylation, or generic oxygenated carbon deposition cannot be excluded. Time-dependent analysis revealed a transition from oxygen-rich functional layers at short plasma exposure to carbon-rich overlayers at longer exposure, suggesting a fragmentation-recombination mechanism that is consistent with the formation of a metal-lactate-like interfacial region and a carbon-rich overlayer, while alternative interpretations related to signal attenuation and non-uniform coverage remain possible. Antibacterial testing revealed that the observed bacterial responses were not attributable to an intrinsic antibacterial property of the deposited films, but were instead strongly dependent on the underlying substrate chemistry and exposure time. C1100 retained the inherent antibacterial activity of copper, SUS430 showed no activity due to the absence of film formation, and SPCC exhibited only a transient effect attributed to lactic-acid-induced local acidification. Overall, the study elucidates the plasma-assisted deposition mechanism of lactic-acid-derived coatings under open-air conditions and highlights the critical role of interface chemistry in achieving stable and substrate-independent functional properties. Full article

Magnesium phosphate cement (MPC) is a type of rapid-hardening inorganic cementitious material, which has important application value in rapid road repair, solidification of hazardous and radioactive waste, and other fields. However, it suffers from excessively fast setting and hardening and a short working time retention, which severely restrict its engineering application. Therefore, the development of high-efficiency set retarders is of great significance for optimizing MPC performance, enhancing its construction workability, and expanding its application scope. In this study, the effect of sodium polyacrylate (PAAS) on the setting and hardening of magnesium potassium phosphate cement (MKPC) was investigated by testing the setting time and fluidity at a low water-to-solid ratio (W/S = 0.18). Through pH and electrical conductivity measurements, combined with XRD, TG/DTG, and FTIR characterizations, we elucidated the retarding mechanism of PAAS on MKPC using a high water-to-solid ratio (W/S = 10). The results indicate that the setting time of MKPC is positively correlated with the PAAS dosage, whereas the fluidity and compressive strength exhibited a negative correlation with the PAAS dosage. Additionally, PAAS reduces the total heat release and the heat release rate of MKPC. The addition of PAAS increased the pH of the suspension, thereby reducing the solubility of MgO, but did not inhibit the dissolution of KH₂PO₄  The carboxylate groups in PAAS chemically reacted with Mg²⁺ on the surface of MgO to form magnesium carboxylate complexes (Mg-PAA), which remained as precipitates in the MKPC suspension system, thus reducing the amount of available Mg²⁺ participating in the hydration reaction. Furthermore, PAAS had no effect on the final precipitate composition at the end of hydration, which was composed of MgKPO₄·6H₂O  and Mg₃(PO₄)₂·22H₂O  in all cases. Full article

Konjac glucomannan (KG) is a biocompatible polysaccharide with limited functional performance in its native form, motivating modification strategies to enhance its properties. This study investigates the effect of gallic acid (GA) functionalization on the structural, physicochemical, mechanical, antioxidant, and biological properties of KG-based films. FTIR analysis confirmed that GA interacts with KG primarily through non-covalent hydrogen bonding without disrupting the polymer backbone. Modification with GA enabled concentration-dependent tuning of surface energy, roughness, hydration behavior, and water vapor permeability. Mechanical testing revealed a significant increase in stiffness and tensile strength accompanied by reduced elongation at higher GA contents. Antioxidant activity was markedly enhanced even at low GA concentrations. All films exhibited excellent hemocompatibility, while cytocompatibility toward human fibroblasts depended on GA content. Optical analysis indicated moderate color changes without severe discoloration. Overall, GA functionalization effectively improves the functional performance of KG films while preserving polymer integrity. Hence, GA-modified KG films as promising candidates for biomedical applications (like wound dressing) requiring antioxidant activity, controlled hydration, and biocompatibility. Full article

Frozen surimi, a commonly used raw material in processed aquatic products, is vulnerable to repeated freeze–thaw fluctuations that accelerate protein denaturation and quality loss. In this study, root-derived Flammulina velutipes polysaccharides (FVPs) were extracted from the root-like portion of enoki mushroom, and surimi supplemented with 2% FVP and a blank control (CK) were stored at −18 °C and subjected to a total of five freeze–thaw cycles. The effects of FVP on myofibrillar protein (MP) characteristics and the storage quality of catfish surimi during the freeze–thaw cycles were analyzed. Compared with CK, FVP markedly alleviated the deterioration of water-holding capacity, gel strength, and MP solubility throughout freeze–thaw cycling. It also effectively inhibited the increase in thiobarbituric acid reactive substance (TBARS) values and MP aggregation and delayed the rate of decrease in the storage modulus (G′) and loss modulus (G″) of surimi. Additionally, low-field nuclear magnetic resonance (LF-NMR) further showed that FVP limited the conversion of immobilized water to free water, indicating enhanced water retention under repeated freeze–thaw stress. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses revealed that FVP stabilized the secondary structure of MPs, making the microstructure of surimi more uniform and compact. The results of this study indicate that FVP exhibited significant cryoprotective effects during freeze–thaw cycles of surimi relative to the untreated control group, providing a theoretical basis for its potential application in aquatic product storage. Full article

Poly(lactic acid) (PLA) films containing two different hemp-derived essential oils (EOs), Carmagnola CS (Carm) and Futura 75 (Fut), at 1, 5, and 10% wt were successfully produced via solvent casting for packaging applications. The influence of EO presence, type, and concentration on the chemical, morphological, and thermal properties of the PLA-based films was investigated. In addition, radical-scavenging activity, water transport properties, and antimicrobial performance were evaluated to assess the effect of EOs on the structural and functional characteristics of the resulting packaging materials. FTIR spectroscopy confirmed the successful incorporation of the hemp essential oils Carm and Fut into the polymer matrix, with a concentration-dependent effect that is more pronounced for Fut than for Carm. In the second heating run, evaluated by DSC measurements, both EOs lowered T_g from 60.3 °C (PLA) to 52.0 °C for PLA_10 Carm and 55.1 °C for PLA_10 Fut. The EOs act as plasticizers in the PLA matrix, improving the deformation at break. Gas barrier measurements showed that permeability decreased from 3027 ± 300 Barrer (PLA) to (2499 ± 44) Barrer in PLA_10 Carm and 2623 ± 130 Barrer in PLA_10 Fut, with a corresponding reduction in diffusivity. The barrier improvement factor reached 17% for Carm and 15% for Fut, confirming the enhanced barrier performance of PLA_EOs films. DPPH assays showed that PLA_EOs films retained most of the antioxidant activity of the free oils, with only a 10–15% reduction for PLA_Fut and no significant loss for PLA_Carm after one week. After one month, the activity of Carm in PLA film decreased by 18%, whereas the performance of its free form remained unchanged, confirming the superior and more stable radical scavenging capacity of Carm compared to Fut. Overall, the study demonstrates that hemp essential oils can be effectively integrated into PLA without compromising structural integrity, while preserving antioxidant performance and enhancing water barrier properties, supporting their potential as sustainable active packaging components. Full article

The enhancement of startup and performance in a Tetradesmus obliquus-polyurethane sponge biofilm system was investigated via the regulation of the phytohormone Indole-3-acetic acid (IAA). IAA supplementation at 1 and 5 mg/L increased biofilm biomass and chlorophyll a content, with the maximum biofilm biomass reaching 48.2 mg/g, and improved nutrient removal performance under shock-loading conditions, particularly for total nitrogen (TN) and total phosphorus (TP). IAA treatment was associated with EPS remodeling, including an increase in the protein/polysaccharide ratio to 0.68 and a 16% enrichment in tryptophan-like protein components. These EPS-related changes coincided with a decrease in the absolute zeta potential to −2.49 mV, which may be relevant to enhanced initial biofilm development. The corresponding EPS-related changes were characterized by three-dimensional excitation–emission matrix (3D-EEM) and Fourier transform infrared (FTIR) analyses using representative concentrations. Furthermore, the IAA-treated biofilm showed improved resilience under low, medium, and high loading conditions, with the most favorable TN removal reaching 87% at 1 mg/L IAA. These results suggest that IAA supplementation at 1 and 5 mg/L can promote microalgal biofilm start-up and improve nutrient-removal resilience under the tested conditions, with 5 mg/L showing the strongest response in biofilm growth and structural characterization. Full article