Search Results (5,563)

A magnetic chitosan composite was applied to study the adsorption of nanoplastics (NPs), prepared from single-use plastic bottles and packaging materials by mechanical fragmentation (MF) and nanoprecipitation (NPR), on magnetic biopolymer. The resulting polystyrene (PS) and polyethylene terephthalate (PET) samples were characterised by SEM, TEM, DLS, zeta potential and ATR-FTIR. The magnetic chitosan composite (MCSC) was prepared by synthesising Fe₃O₄ nanoparticles and modifying chitosan through crosslinking. Batch experiments were conducted to study the adsorption of PSNPR, PETNPR, and PETMF nanoplastics on the magnetic chitosan composite. Changes during the adsorption process were monitored using UV–Vis spectroscopy. The maximum efficiencies of PSNPR and PETMF are 97% and 94%, respectively, at pH 5, whereas the maximum efficiency of PETNPR is 94% at pH 6. The Langmuir maximum adsorption capacity (q_m) values for PSNPR, PETNPR, and PETMF are 26.7, 13.8, and 19.4 mg g⁻¹, respectively. The Freundlich and Langmuir isotherms, thermodynamic studies, as well as pseudo-first-order and pseudo-second-order models, were applied to study the adsorption behaviour of nanoparticles on the magnetic chitosan composite. The XPS and FT-IR data for pristine and adsorbed nanoplastics as well as modelling results indicated complex adsorption mechanisms. Full article

Water contamination by acetaminophen, a compound difficult to remove via conventional treatments, has become a growing environmental concern due to its excessive consumption in recent years. Among emerging methods for removing this pollutant, heterogeneous photocatalysis is a promising option that enables catalyst recovery and reuse. In this research, Ti-SBA-15 materials with different Si/Ti molar ratios were synthesized by a one-step sol–gel method to improve Ti dispersion within the SBA-15 silica framework. A detailed characterization of the materials was carried out using XRD, SEM, ICP-OES, N₂ physisorption, UV-Vis-DRS, XPS, and zeta potential techniques. The results showed that the characteristic hexagonal mesoporous structure of SBA-15 was largely preserved at high Si/Ti ratios, while ICP-OES analysis showed that the synthesis method allowed Ti incorporation close to the theoretical Si/Ti molar ratio for most synthesized materials. As the Ti content increased, the specific surface area decreased, whereas the band gap energy increased. The UV-Vis-DRS spectrum showed an absorption band around 230 nm, which is commonly associated with ligand-to-metal charge transfer transitions in isolated Ti species with tetrahedral coordination. Together with the XPS results, these findings suggest that the Ti incorporated into the silica framework is predominantly in tetrahedral coordination. Small amounts of Ti in Ti-SBA-15 materials are sufficient to promote photocatalytic acetaminophen degradation, without requiring significant anatase formation. Catalyst dosage and solution pH significantly influenced system performance, with higher degradation rates observed under acidic conditions. However, the rapid disappearance of acetaminophen did not directly translate into high mineralization, as aromatic intermediates are difficult to break down into carboxylic acids. Consequently, the maximum mineralization achieved was 50%, obtained with a catalyst concentration of 50 mg/L at pH 6. The proposed reaction scheme successfully predicted the experimental data. These results show that the Ti-SBA-15 system possesses a high capacity for degrading acetaminophen; however, complete mineralization is limited by the slow oxidation rate of aromatic intermediates, making the control of subsequent degradation stages a key factor in improving the overall efficiency of the photocatalytic process. Full article

Bovine mastitis is a major problem affecting dairy production, and teat disinfection is important for reducing the risk of bacterial infection. Curcumin has antimicrobial properties, but its poor water solubility limits its use in aqueous formulations. This study aimed to develop chlorhexidine–curcumin nanoformulations (CCNs) and perform preliminary in vitro screening of these nanoformulations as candidate teat-dipping formulations. Four CCNs containing increasing concentrations of curcumin (0%, 0.1%, 0.5%, and 0.9% w/v; CCN0, CCN0.1, CCN0.5, and CCN0.9, respectively) were prepared. CCN0, CCN0.1, and CCN0.5 were formulated as oil-in-water nanoemulsions, whereas CCN0.9 was prepared as a curcumin-β-cyclodextrin inclusion complex. The physicochemical properties were characterized, and the antibacterial activity was evaluated in vitro by agar well diffusion against six mastitis-associated pathogens. CCN0.9 showed the largest inhibition zones overall (20.07 ± 1.05–28.85 ± 1.05 mm; p < 0.05), while CCN0.1 and CCN0.5 showed activity comparable to or greater than that of commercial teat dips against several pathogens. CCN0.5 showed the most favorable nanoemulsion characteristics, with a particle size of 94.77 nm and a zeta potential of −46.57 mV. Overall, CCNs demonstrated antibacterial activity against mastitis pathogens, supporting their potential as candidate teat-dip formulations. Further teat irritation and in vivo efficacy studies are needed before field application. Full article

Gamma irradiation offers a simple and reagent-free strategy for tailoring the physicochemical properties of starch for the development of functional biomaterials, although its application in protein delivery systems remains largely unexplored. In this study, starch was irradiated at doses between 50 and 500 kGy and combined with chitosan to produce composite particles for the adsorption of Neospora caninum membrane proteins (NcMP), with the aim of developing a potential intranasal vaccine delivery platform. Irradiation induced progressive oxidation and depolymerization of starch, as evidenced by Fourier transform infrared (FTIR) analysis, increased apparent amylose content, reduced molecular weight and hydrodynamic diameter, and shifted the zeta potential to −13.4 mV, leading to the selection of starch irradiated at 300 kGy for particle preparation. The resulting starch–chitosan particles exhibited spherical morphology and, following protein adsorption, formed a protein-associated nanosystem with a hydrodynamic diameter of 105.7 nm and a zeta potential of −18.8 mV. Protein association was confirmed by fluorescence co-localization and an adsorption efficiency of 34%. These findings demonstrate that gamma irradiation is an effective approach for engineering starch-based composite particles with physicochemical characteristics suitable for protein association and intranasal delivery, supporting their potential as a versatile platform for protein subunit vaccine formulations. Full article

Background/Objectives: Shikonin is a bioactive compound with promising pharmaceutical potential, particularly for anti-inflammation and ability to inhibit proliferative scar formation. However, its applications are limited by poor photostability. Therefore, this research aimed to develop and optimize shikonin-loaded NLC to improve the photostability of shikonin. The optimized NLC formulation was subsequently incorporated into a hydrogel matrix to fabricate a dermal patch, providing a potential alternative for topical scar treatment and self-care application. Methods: Shikonin-loaded NLCs were developed, optimized, and evaluated for physicochemical properties, entrapment efficiency, photostability, and in vitro release. The optimized NLC was incorporated into a hyaluronic acid–carboxymethyl cellulose hydrogel matrix to fabricate and evaluate an NLC-based dermal patch. Results: The optimized shikonin-loaded NLC exhibited a particle size of 104.94 nm with a narrow polydispersity index of 0.15, and a zeta potential of −34.34 ± 0.02 mV. The NLC achieved high entrapment efficiency (>90%). The NLC significantly enhanced the photostability of shikonin, by increasing the percentage of shikonin remaining after light exposure from 37.36 to 64.55% (p < 0.05). In addition, the cumulative shikonin release over 12 h was 15.61 ± 4.18%, following Korsmeyer–Peppas model. A combination of hyaluronic acid and carboxymethyl cellulose (1% w/w) was employed as the biopolymer for the hydrogel dermal patch. The shikonin-loaded NLC-based dermal patch exhibited favorable physicochemical characteristics. Conclusions: The NLC demonstrated enhanced photostability and release properties, which are preserved upon their integration into the hydrogel. The incorporation of shikonin-loaded NLC into a hydrogel matrix provides a viable strategy for stabilizing this light-sensitive bioactive compound. Consequently, this NLC-loaded hydrogel system represents a promising platform for future topical dermal delivery in pharmaceutical and cosmetic applications. Full article

Black titanium dioxide nanoparticles (bTiO₂ NPs) have emerged as promising materials for light-driven applications due to their extended optical absorption and reduced environmental concerns compared with heavy-metal-based quantum dots. In this work, bTiO₂ NPs were synthesized via a simple, low-cost, and environmentally friendly one-pot aqueous method. X-ray diffraction analysis confirmed the formation of the anatase TiO₂ phase. Transmission electron microscopy (TEM) was used to determine the particle size finding a value of 10.3 ± 3.4 nm. The colloidal dispersion exhibited a positive zeta potential of +47.5 mV, indicating favorable electrostatic stabilization. Optical characterization revealed strong UV absorption at 280 nm, together with a pronounced NIR absorption band centered at approximately 804 nm, consistent with optical transitions associated with sub-band gap electronic states. The analysis of X-ray photoelectron spectroscopy (XPS) to the Ti 2p core-level confirmed the presence of 7.3% of Ti³⁺ species that can explain the NIR absorption. Photoluminescence analysis showed an emission band at 430–433 nm. Under 808 nm NIR irradiation, with an initial temperature of 37 °C, the bTiO₂ NPs exhibited pronounced photothermal heating, reaching a maximum temperature increase of 30.2 °C and a photothermal conversion efficiency of 21.6%. The photothermal response increased with nanoparticle concentration under the evaluated experimental conditions, demonstrating concentration-dependent NIR photothermal heating. In vitro cytotoxicity assays showed high cell viability at the lower concentration tested, exceeding 100% at 50 µg/mL, whereas cell viability decreased to approximately 60% at 500 µg/mL. Overall, these results indicate that the synthesized bTiO₂ NPs exhibit extended NIR absorption, concentration-dependent photothermal heating, and concentration-dependent effects on cell viability, supporting their potential for further investigation as photothermal nanomaterials. Full article

Eucalyptus kraft pulping represents an important source for the production of lignin-containing cellulose nanofibrils (LCNF); however, the influence of controlled residual lignin levels on fibrillation energy demand and suspension stability remains poorly understood. This study evaluated the effect of residual lignin on the chemical properties of Eucalyptus urograndis kraft pulps, energy consumption during mechanical fibrillation over 20 passes in a Super Masscolloider, and the colloidal stability of the resulting suspensions. Brown kraft pulp was subjected to delignification treatments under mild (60 °C, 3 min) and severe (95 °C, 60 min) conditions, resulting in pulps with residual lignin contents of 3.63%, 1.77%, and 0.46%, respectively. Delignification reduced the kappa number from 29.59 in the brown pulp to 16.16 and 1.63 after mild and severe treatments, respectively, while pulp viscosity varied according to treatment severity. Energy consumption increased progressively with the number of passes and was strongly affected by residual lignin content. After 20 passes, the brown pulp (3.63% lignin) showed the highest energy consumption, reaching approximately 0.109 kWh, compared with 0.016 and 0.018 kWh for pulps containing 1.77% and 0.46% residual lignin, respectively. Despite these differences in energy consumption, all LCNF suspensions exhibited higher absolute zeta potential values under neutral to alkaline conditions, ranging from approximately −24 to −37 mV. These findings indicate that controlled delignification was associated with lower energy consumption during mechanical fibrillation while maintaining favorable electrokinetic behavior of the colloidal suspensions. Therefore, controlling residual lignin content may represent a strategy for balancing lignin removal, fiber preservation, and energy consumption during mechanical fibrillation under the conditions evaluated in this study. Full article

The present study reports the development of a novel botanical hybrid system obtained through the integration of Geranium robertianum L. phytochemicals, green-synthesized silver nanoparticles, and chlorophyll-loaded soybean lecithin biomimetic membranes. The proposed strategy combines the reducing and stabilizing capacity of plant-derived metabolites with the structural and functional advantages of membrane-inspired lipid assemblies. Silver nanoparticles were synthesized using aqueous Geranium robertianum extract, while biomimetic lipid vesicles were prepared from soybean lecithin and subsequently assembled into hybrid bioentities through a self-organization process. The obtained structures were characterized by UV–Vis spectroscopy, fluorescence spectroscopy, FTIR–ATR analysis, dynamic light scattering, zeta potential measurements, scanning electron microscopy, atomic force microscopy, and energy-dispersive X-ray spectroscopy. Optical investigations support the formation of phyto-capped silver nanoparticles and their successful incorporation into chlorophyll-containing biomimetic membranes. The hybrid structures exhibited improved colloidal stability, appropriate nanoscale dimensions, and characteristic morphological features indicative of efficient integration of the lipid and metallic components. Antioxidant and antibacterial investigations highlighted the combined contribution of the phytochemicals, silver nanostructures, and phospholipid matrix. These findings establish a versatile, environmentally friendly platform that bridges phytochemistry, nanotechnology, and biomimetic engineering, and may provide new opportunities for the development of multifunctional antimicrobial systems. Full article

A pH-responsive polymer-coated hybrid colloidal micellar nanocarrier was developed as a mixed lipid–polymer nanostructure for the delivery and controlled release of Diclofenac to mildly acidic environments (inflamed or tumor tissues). The particles, composed of lecithin, cholesterol, chitosan, sodium cholate, and sodium dodecyl sulfate, remain stable under normal physiological conditions. Synthesized via the thin-film hydration method, the nanocarriers were characterized using turbidimetric analysis, electron microscopy (SEM and TEM), spectrophotometry, HPLC, and capillary electrophoresis. SEM and TEM confirmed a spherical shape, with a diameter of 35–45 nm in the dehydrated state. The particles exhibited good stability, maintaining integrity for over two months at 4 °C and for several hours at 37 °C and 39 °C. The zeta potential was evaluated at −24.7 mV. Decreasing the pH from 7.42 to 6.0 triggered rapid degradation at the beginning of the process, followed by a slowdown throughout the observation period. Quantification showed pH-dependent diclofenac release. This hybrid micellar platform is a feasible stimuli-responsive nanosystem for controlled delivery and effective release of hydrophobic drugs. Full article

Lead-free polymer composites are being developed to reduce occupational radiation exposure associated with nuclear medicine procedures. This study fabricated monolithic and four-layer hybrid Bi₂O₃/WO₃ nanoparticle-filled diglycidyl ether of bisphenol A epoxy composites for attenuating the 140.5-keV photons emitted by technetium-99m (⁹⁹ᵐTc). Bi- and W-containing powders were prepared by wet-chemical precipitation and incorporated into the epoxy matrix at 25 and 50 parts per hundred parts of resin. Alternating B50/W50/B50/W50 (ML-BW50) and reverse-layer configurations were produced by sequential casting with a total specimen thickness of 2.0 cm. The nanoparticle dispersions and cured composites were evaluated using DLS, zeta-potential analysis, FE-SEM–EDX, XRD, FTIR spectroscopy, PBS contact-angle measurements, and supplementary tensile testing. Shielding performance was measured at ⁹⁹ᵐTc activities of 925 MBq (25 mCi) and 6.105 GBq (165 mCi) using an anthropomorphic thorax phantom and an electronic personal dosimeter under a fixed source–shield–detector geometry. The Bi₂O₃ and WO₃ dispersions exhibited Z-average hydrodynamic diameters of 646.41 and 413.38 nm and zeta potentials of −33.70 and −31.65 mV, respectively. FE-SEM and EDX analyses documented compositionally differentiated Bi-rich and W-rich layers in ML-BW50. XRD identified a mixed-phase Bi- and W-containing filler system, including α-Bi₂O₃, bismuth oxide carbonate hydroxide, WO₃, and residual Na₂WO₄·2H₂O, while FTIR spectra retained the characteristic bands of the cured epoxy network. ML-BW50 exhibited a maximum tensile stress of 4.008 MPa, a terminal strain of 74.294%, and a tensile toughness of 2.250 MJ·m⁻³, representing the highest tensile toughness among the investigated epoxy-based formulations. The shielding formulation significantly affected the background-corrected personal dose equivalent, Hp(10), at both activities (both p < 0.0001), and the multilayer specimens reduced Hp(10) by approximately 45–72% relative to their corresponding monolithic composites. ML-BW50 was the most effective lead-free formulation, producing Hp(10) values of 33.15 ± 2.75 and 228.42 ± 6.50 µSv and radiation-shielding efficiencies of 77.42% and 82.70% at 925 MBq and 6.105 GBq, respectively. ML-BW50 and the 0.5-mm lead reference produced statistically comparable Hp(10) values at 925 MBq, whereas ML-BW50 produced a 9.12% lower Hp(10) than lead at 6.105 GBq. For the same 10 × 10 cm projected area, ML-BW50 had a mass of 44.0 g compared with 77.0 g for lead, representing a 42.9% mass reduction, and exhibited a mean PBS contact angle of approximately 102.3°. Collectively, ML-BW50 combined effective ⁹⁹ᵐTc attenuation, reduced specimen mass, differentiated multilayer organization, low PBS wettability, and favorable tensile-energy absorption, supporting its continued development as a lead-free occupational shielding material for nuclear medicine. Full article

In the present work, CeO₂ nanoparticles (NPs) were synthesized greenly using Alexandrian senna leaf extract as a reducing and stabilizing agent. The synthesized nanoparticles were analyzed using several analytical techniques to investigate their physicochemical properties. The average hydrodynamic particle size determined by DLS was 413.9 nm with an average polydispersity index (PDI) of 3.114, and the zeta potential average of the particles was −5.5 mV, showing moderate colloidal stability. The elemental composition of the nanoparticles was verified by energy-dispersive X-ray spectroscopy (EDX), which showed the presence of Ce elements with 72.15% content, O elements with 13.95% content, and C elements with 13.90% content. The antioxidant activity of SA-CeO₂ NPs was assessed by the DPPH free radical scavenging assay, which showed a dose-dependent effect, attaining a maximum scavenging efficiency of 75.61% at 100 µg/mL. Antibacterial activity was evaluated for the strains of Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Klebsiella pneumoniae. In addition, the photocatalytic activity of SA-CeO₂ NPs was tested for the degradation of methylene blue (MB) dye under sunlight. The degradation efficiency was 88.54% after 180 min of exposure, which is a very high photocatalytic efficiency. The results of the kinetic studies showed that the degradation process was pseudo-first-order, with a rate constant of 0.01344 min⁻¹ (R² = 0.96298). The results indicate that the green-synthesized CeO₂ nanoparticles exhibit promising photocatalytic, antioxidant, and antibacterial properties under the investigated conditions, supporting their potential for further investigation in environmental remediation and related applications. Full article

To address the inferior lubricity of synthetic cutting fluids compared with oil-based cutting fluids, a strategy is proposed to improve the cutting performance by exploiting the electroosmotic effect to enhance penetrability at the friction interfaces in the cutting zone. The triboelectrification potential and tribo-emission of charged particles were measured at the accessible major flank face–workpiece interface to characterize the electrical behavior of an alumina ceramic–AISI 52100 steel friction pair. Taking the rake face–chip interface as a representative case, the distribution characteristics of the tribo-induced electric field (TIEF) and the electroosmotic flow field of the cutting fluid within an interfacial capillary were analyzed using COMSOL Multiphysics 5.5 simulations, based on the measured electrical boundary conditions and zeta potentials. Turning tests on AISI 52100 steel with alumina ceramic tools were also conducted under the lubrication of cutting fluids with distinct electroosmotic properties. The simulations indicate that the TIEF can drive electroosmotic flow toward the interior of the interface. The experiments show that the electroosmotic performance of the cutting fluid is positively correlated with its cutting performance. The simulated TIEF intensity increases with increasing cutting speed and depth, and the electroosmotic regulation of cutting performance is correspondingly enhanced. Full article

Foodborne microbial contamination remains a major challenge for the safety and shelf life of poultry and other perishable foods. This study developed a silver nanoparticle (AgNP)-based antimicrobial formulation and evaluated its physicochemical characteristics, antibacterial activity against Escherichia coli, and preliminary concentration-dependent effects on bovine sperm viability. AgNPs were synthesized using a modified glucose–citrate reduction method. UV–Vis measurements showed characteristic surface plasmon resonance maxima within approximately 411–422 nm across the evaluated synthesis experiments. Transmission electron microscopy revealed predominantly quasi-spherical particles with a mean diameter of 23.14 ± 8.31 nm (n = 100), a median diameter of 25.30 nm, and a size range of 5.07–34.88 nm. The mean hydrodynamic radius was 15.47 nm, and the zeta potential was −38.80 ± 0.63 mV, indicating pronounced electrostatic stabilization of the colloidal dispersion. In antibacterial assays, the complete AgNP–chitosan–lactic acid–collagen formulation resulted in complete absence of visible E. coli growth at all tested concentrations, including the lowest evaluated nominal Ag concentration of 6.5 mg/L in the prepared formulation, corresponding to approximately 3.25 µg/mL in the final antibacterial assay mixture, whereas the other tested formulation variants did not achieve complete growth suppression. In the preliminary bovine sperm assay, AgNP dispersion alone caused a concentration-dependent decline in viability, with statistically significant effects observed from 1.37 mg/L onward. These findings demonstrate that the complete multicomponent formulation provides strong antibacterial activity at relatively low nominal Ag concentrations while also highlighting the need for further toxicological and migration assessment. Future studies should validate the formulation in real food matrices and evaluate silver release, migration, and safety under relevant storage and application conditions. Full article

Background/Objectives: Cancer causes high premature death worldwide, with 35 million new cases expected by 2050. Multidrug resistance (MDR), driven by genetic and epigenetic changes, hampers chemotherapy. In this study, polymeric nanoparticles (NPs) were formulated with an organoselenium nucleoside analogue (AFAT-Se) to investigate their potential antitumor activity against MDR tumor cells, especially when co-administered with conventional chemotherapeutic agents. Methods: Various in vitro methods were used to assess antitumor activity, effects on non-tumor cells (L929 fibroblasts), and synergy with drugs like doxorubicin, docetaxel, paclitaxel, and methotrexate. Results: The NPs measured below 200 nm, exhibited a low polydispersity index, a negative zeta potential, and high drug content and encapsulation efficiency. AFAT-Se-NPs induced a time- and concentration-dependent reduction in L929 cell viability, with lower effects observed after 24 h and a concentration-dependent toxicity after 72 h. They exhibited limited efficacy against a resistant/MDR cell line (NCI/ADR-RES) even at high doses, but enhanced efficacy when combined with conventional antitumor agents, thereby reducing tumor cell viability more efficiently. In the 3D spheroid model, the combination of AFAT-Se-NPs + doxorubicin showed marked growth inhibition, reducing spheroid size to just 53.2% of its initial area. Likewise, the same combination treatment significantly enhanced the antimigratory effect, yielding a migration rate of only 10.30% versus 55.24% in the untreated control. Finally, the internalization of the NPs was confirmed by fluorescence microscopy. Conclusions: AFAT-Se-NPs have good physicochemical properties, time- and concentration-dependent effects on non-tumor cells, limited cytotoxic activity as a single agent against MDR cells and boost chemotherapy when combined with standard antitumor drugs. Co-administering NPs with doxorubicin slowed cell migration and tumor growth in a 3D model, suggesting that this approach could enhance treatment activity in an MDR cell model and improve cancer therapy. Overall, these findings provide a preliminary basis for further investigation of AFAT-Se-NPs. Full article

Peroxymonosulfate-based oxidation inevitably generates sulfate in the effluent, which may stimulate sulfate-reducing bacteria and pipeline corrosion. Sulfate-polishing adsorbents suitable for acidic effluent remain limited. Herein, we report an ethanol-assisted solvothermal strategy to tailor surface hydroxyl speciation on amorphous ZrO₂. The optimized material reached adsorption equilibrium within 10 min and showed an adsorption capacity of 110.6 mg/g. In fixed-bed operation using acidic sulfate-containing feed, the dynamic capacity was 82.9 mg/g, and the 50% breakthrough occurred at 3400 bed volumes. The terminal hydroxyl fraction increased from 15.2% to 59.8% as the ethanol/water volume ratio increased from 3:1 to 10:1. Ethanol addition is proposed to reduce hydrogen-bond-network connectivity, thereby suppressing condensation into bridging-hydroxyl. Terminal-hydroxyl abundance, estimated by thermogravimetric mass spectrometry (TG-MS) combined with solid-state ¹H magic-angle-spinning nuclear magnetic resonance (¹H MAS NMR) showed a positive trend with adsorption capacity. Site-blocking tests established an 87% terminal-hydroxyl-associated contribution to sulfate uptake. Zeta-potential and electrostatic-potential analyses supported preferential sulfate approach to terminal-hydroxyl-rich positive domains, whereas density functional theory (DFT) identified dual-site binding to terminal hydroxyls on separate Zr centers as the most stable configuration. These results identify regulation of hydroxyl speciation as a dopant-free strategy for sulfate polishing after peroxymonosulfate oxidation. Full article