Search Results (2,054)

Zinc-based coatings are insufficient as surface coatings; they corrode rapidly and can cause long-term damage to subsea pipelines and other instruments. Therefore, this research was undertaken by manufacturing a sacrificial nano-reinforced Zn coating combined with additives via electrodeposition onto a mild steel S235 substrate, which provides excellent corrosion resistance under severe marine conditions. The electrodeposited coatings were characterized using SEM/EDS and XRD, revealing the effective incorporation of cerium oxide nanoparticles and high-quality graphene (Gr) in the zinc matrix. Vickers microhardness measurements, mechanical resilience, and surface roughness of the Zn-CeO₂-Gr coating showed an inverse correlation between improved microhardness (+65.85%) and mechanical resilience (+31.49%), while surface roughness decreased (−81.48%) compared to pure zinc electrodeposited coatings. These characteristics indicate grain refinement and greater reliability under mechanical stress. Electrochemical impedance spectroscopy (EIS) and DC polarization measurements indicate a significant improvement in corrosion resistance compared to pure zinc, due to the synergistic effect between graphene and cerium oxide nanoparticles, which reduces the cathodic activity of the surface. These findings offer promising applications for cutting-edge materials in saline environments. Full article

The green synthesis of nanomaterials has emerged as a sustainable and environmentally friendly approach, gaining significant attention in recent years for its potential in a wide range of multifunctional applications. Among these materials, zinc oxide nanoparticles (ZnO NPs) stand out due to their remarkable versatility and effectiveness in fields such as industry (food, chemistry, and cosmetics), nanomedicine, cancer therapy, drug delivery, optoelectronics, sensors, and environmental remediation. This study focuses on bioinspired strategies for the facile synthesis of ZnO NPs, employing natural polysaccharide gums as mediators. Acting as both reducing and stabilizing agents, natural gums not only facilitate the eco-friendly production of ZnO NPs but also enhance their stability and functionality. Natural gum-mediated green synthesis typically yields stable, spherical ZnO particles, often in the 10–100 nm range. Typical reaction conditions are the use of zinc acetate dihydrate or zinc nitrate (0.01–0.5 M) as precursors, with low gum concentrations of 0.1–1.0% (w/v) in distilled water, alkaline conditions (pH from 8 to 12), often achieved by adding NaOH, which aids in the reduction and capping by the gum, at reaction temperature between 60 °C and 80 °C, under continuous stirring. The dried precipitate is often calcined at 400 °C to 600 °C to remove organic residues and enhance crystallinity. This approach underscores the potential of biopolymer-assisted synthesis in advancing green nanotechnology for sustainable and practical applications. Utilizing environmentally benign materials such as natural gums for the synthesis of ZnO NPs offers significant advantages, including enhanced eco-friendliness and biocompatibility, making them suitable for a wide range of applications without the involvement of toxic reagents. This review provides an in-depth analysis of the synthesis and characterization techniques employed in the eco-friendly production of ZnO NPs using different natural gums from biological sources and its environmental applications (e.g., pollutant removal and increased agriculture sustainability). Full article

The development of sustainable packaging materials with advanced functional properties is a key priority for the food industry. In this study, chitosan (CS)-based nanocomposite films incorporating titanium dioxide (TiO₂), zinc oxide (ZnO), hybrid ZnO_TiO₂ nanoparticles, lignin (LG), and nanolignin (nLG) were synthesized and comprehensively characterized. Structural analyses (FTIR, XRD, SEM) confirmed strong intermolecular interactions and homogeneous nanoparticle dispersion, particularly for TiO₂ and low ZnO concentrations. Mechanical testing showed that TiO₂ and ZnO significantly enhanced tensile strength (up to fourfold) and elongation at break. Among the prepared nanocomposite films, CS-TiO₂ films at 2 wt% exhibited the best balance of mechanical performance and antioxidant activity. Subsequent incorporation of LG and especially nLG into the CS-TiO₂ matrix further enhanced flexibility and toughness, antioxidant efficiency, and radical-scavenging activity above 90%, and improved UV-shielding capacity by reducing light transmittance. Moreover, antibacterial testing against Escherichia coli demonstrated that CS/TiO₂/nLG films achieved the highest reduction (~46%), attributed to synergistic electrostatic, oxidative, and phenolic mechanisms. Overall, CS/TiO₂/nLG nanocomposites emerge as multifunctional, biodegradable films with significant potential for next-generation active food packaging applications. Full article

Background/Objectives: Nanostructured biomaterials based on natural polymers have gained increasing attention in pharmaceutics due to their biocompatibility, multifunctionality, and diverse biomedical applications. This novel study aimed to biofabricate chitosan-doped zinc oxide nanocomposites (CS-ZnONCs) using Leucas aspera leaf extract and to evaluate their physicochemical properties and in vitro biomedical performance. Methods: CS-ZnONCs were synthesized using L. aspera leaf extract through a green precipitation approach, and the resulting nanocomposites were characterized by various spectroscopic techniques. The in vitro antioxidant, antibacterial, and anti-inflammatory activities were evaluated, while wound-healing potential was assessed using L929 fibroblast cell migration assays. Results: UV–visible analysis confirmed the formation of CS-ZnONCs, with a characteristic absorption peak at 362 nm, and FTIR spectra indicated the presence of various important functional groups. XRD results demonstrated the crystalline nature of ZnO within the chitosan matrix. Well-dispersed, quasi-spherical nanoparticles with an average size of 44 ± 3.1 nm were identified by HR-TEM, and a positive zeta potential (+9 mV) suggested considerable colloidal stability. CS-ZnONCs showed a high swelling capacity (88 ± 2.75% for 2%) and significant phytocompound release (65.38 ± 2.79% at pH 7.4). The CS-ZnONCs showed significant antioxidant activity (ABTS of 88.19 ± 1.59%), notable antibacterial efficacy against Staphylococcus aureus (18.78 ± 0.98 mm) and Escherichia coli (17.14 ± 0.96 mm), and significant anti-inflammatory activity (82.12 ± 1.47% membrane stabilization). In vitro biocompatibility and wound-healing assays revealed significant cytocompatibility in Vero cells, with 98.75 ± 1.17% cell viability observed, whereas the fibroblast migration assay demonstrated near-complete wound closure (96.55 ± 6.46%). Conclusions: The green-synthesized CS-ZnONCs exhibit favorable physicochemical properties, biocompatibility, and multifunctional biological activities, supporting their potential as a promising sustainable biomaterial nanomedicine for pharmaceutical formulations, wound healing, and regenerative medicine applications. Full article

Background: The global rise in antimicrobial resistance (AMR) has created an urgent need for innovative antibacterial strategies and localized delivery systems. This study aimed to develop and characterize electrospun poly (vinyl alcohol) (PVA) nanofibers co-loaded with atorvastatin (ATR) and zinc oxide (ZnO) nanoparticles for use as a multifunctional topical platform for wound healing and infection control. Methods: ZnO nanoparticles were prepared via ball milling and characterized for size and zeta potential. Four PVA-based nanofiber formulations were fabricated using electrospinning: blank (F1), ZnO-loaded (F2), ATR-loaded (F3), and ATR/ZnO co-loaded (F4). The nanofibers were evaluated for morphology, thermal properties, crystallinity, and drug release. Antibacterial efficacy was tested against S. aureus, S. epidermidis, MRSA, and P. aeruginosa using broth microdilution and checkerboard assays. Biocompatibility and wound healing potential were assessed via MTT and fibroblast scratch assays on human foreskin fibroblasts (hFFs). Results: SEM imaging confirmed the production of uniform, bead-free nanofibers. ATR and ZnO nanoparticles were successfully incorporated in the nanofiber. The co-loaded formulation (F4) demonstrated a sustained release profile, releasing approximately 78.7% of ATR over 24 h. While all treatments showed limited activity against P. aeruginosa, the ATR/ZnO co-loaded nanofibers exhibited significantly enhanced antibacterial activity against Gram-positive strains, achieving the lowest MIC values (1.5–2.0 mg/mL). Synergy analysis confirmed an enhanced effect with ATR and ZnO against MRSA. Furthermore, F4 achieved the highest wound closure rate of 92.41% in 24 h while maintaining acceptable cytocompatibility. Conclusions: The integration of ATR and ZnO into PVA nanofibers provides an enhanced antibacterial effect consistent with the synergistic potential observed between free agents targeting Gram-positive wound pathogens. The platform’s ability to simultaneously inhibit bacterial growth and promote rapid fibroblast migration positions it as a promising localized therapeutic for managing infected wounds. Full article

Streptococcus sanguinis (S. sanguinis) is an oral commensal and early colonizer of the tooth surface that contributes to dental biofilm homeostasis. Zinc oxide nanoparticles (ZnO NPs) are often incorporated into dental restorative materials to enhance mechanical performance and confer antibacterial properties; however, their effects on S. sanguinis have not been thoroughly studied. Here, we investigated the antimicrobial and antibiofilm efficacy of ZnO NPs against this bacterial species. ZnO NPs exhibited a minimal inhibitory concentration (MIC) of 100 µg/mL and caused rapid, dose-dependent suppression of intracellular ATP levels and overall metabolic activity within 2–4 h of exposure. ZnO NPs induced reactive oxygen species (ROS) production in a dose-dependent manner. The free radical scavenger α-tocopherol partly prevented the antibacterial effect of ZnO NPs, suggesting that lipid peroxidation contributes to ZnO NP-mediated toxicity, although it is not the sole mechanism involved. Short-term exposure (2 h) to ZnO NPs did not significantly affect membrane integrity or cellular morphology, whereas prolonged treatment (24 h) resulted in pronounced membrane permeabilization, membrane hyperpolarization, and cellular swelling. Computational morphometric analyses of high-resolution scanning electron microscopy (HR-SEM) images of planktonic growing bacteria after a 24 h treatment confirmed a significant, dose-dependent increase in cell surface area and surface roughness. Importantly, ZnO NPs also reduced the metabolic activity and compromised the structural integrity of mature, preformed biofilms. Collectively, these findings demonstrate that ZnO NPs exert antimicrobial and antibiofilm effects against S. sanguinis through early metabolic inhibition associated with oxidative stress followed by progressive membrane dysfunction. Full article

Nanotechnology, based on nanoparticles, has become an emerging interdisciplinary tool in reproductive biotechnology, offering innovative opportunities to improve fertilization efficiency and reproductive performance in farm animals. The purpose of this review is to provide an updated synthesis of current research on nanoparticle-based approaches that enhance in vitro fertilization outcomes and other assisted reproductive technologies. The focus is on the biological mechanisms, potential benefits, and limitations of nanoparticle use in animal reproduction. Nanoparticles—including gold, silver, zinc oxide, selenium, and magnetic iron oxide—exhibit distinctive physicochemical properties that enable targeted interactions with gametes and reproductive cells. When used in semen extenders or culture media, nanoparticles improve sperm motility, acrosome and membrane integrity, and reduce oxidative stress and apoptosis. These effects contribute to enhanced fertilization rates and higher embryo developmental competence. In addition, nanoparticles can function as carriers for hormones, antioxidants, and growth factors, stabilizing reagents essential for oocyte maturation, sperm capacitation, and early embryo culture. The review also discusses nanopurification (selectively isolating and removing particles) and nanosorting (separating or organizing nanoscale objects) techniques that allow for non-invasive selection of viable gametes, and fluorescence- and magnet-assisted sorting systems that increase precision in sperm sexing. The mechanical aspects of nanoparticle–cell interactions are analyzed, emphasizing the influence of particle size, dose, and surface modification on both biological efficacy and cytotoxicity. Safety, toxicological concerns, and regulatory frameworks—including International Organization for Standardization (ISO) standards and European Commission recommendations—are critically reviewed to highlight the need for harmonized biocompatibility criteria. Although nanoparticle use in animal reproduction remains largely experimental, accumulated evidence demonstrates its potential to improve reproductive efficiency and reduce economic losses. Integrating nanoparticle-based systems with existing reproduction platforms may represent a transformative step toward sustainable and precision-driven livestock breeding. Full article

Silica-supported zinc (II)–Schiff-base complexes were prepared through a simple and high-yield immobilization strategy and evaluated as heterogeneous catalysts for the ring-opening polymerization (ROP) of lactide. Silica gel and silica nanoparticles were employed as supports to assess the influence of support morphology and textural properties on catalytic performance. Comprehensive characterization by AAS, BET, SEM, and SEM–EDS confirmed effective anchoring of the Zn complexes, homogeneous metal distribution, and support-dependent textural modifications. The supported catalysts were active in the bulk ROP of racemic and enantiopure lactide, affording PLA with high conversions and moderate dispersities. Silica-gel-supported systems exhibited high and reproducible activity over a wide range of conditions, whereas catalysts supported on silica nanoparticles showed a stronger dependence on reaction time and ligand electronic effects, highlighting the key role of the support in modulating active site accessibility and chain growth. Microstructural and thermal analyses confirmed the formation of atactic PLA from rac-lactide and stereoregular PLLA from L-lactide. Overall, this study demonstrates that silica-supported zinc(II)–Schiff-base complexes constitute an effective and versatile heterogeneous platform for lactide ROP and underscore the importance of support properties in the rational design of sustainable catalysts for biodegradable polyester synthesis. Full article

Zinc oxide (ZnO) and zinc sulfide (ZnS) nanocomposites represent promising multifunctional photocatalysts due to their complementary band structures and synergistic charge separation. ZnO–ZnS nanocomposites with varied ZnS content were synthesized to elucidate the composition–structure–property relationships governing their multifunctional performance. Structural characterization using XRD, SEM/EDS, Raman spectroscopy, and XPS confirmed the coexistence of wurtzite crystalline phases of ZnO and ZnS. SEM analysis revealed ZnS fine deposition on the ZnO surface. XPS measurements showed a gradual increase in the amount of ZnS on the ZnO surface with increasing sulfide content and a shift in the valence band maximum from 2.32 eV (pure ZnO) to 0.77 eV (pure ZnS). Optical measurements (IR, UV–Vis diffuse reflectance, photoluminescence) demonstrated that, despite the evolution of vibrational and luminescence features characteristic of ZnS, the apparent band gap remained nearly constant at 3.16–3.18 eV across the series. Photocatalytic methylene blue (MB) degradation followed pseudo-first-order kinetics, peaking for ZN_2 (1% ZnS, k_app = 103 × 10⁻³ min⁻¹), which is 1.7 times higher than for pure ZnO. This enhanced performance is consistent with an S-scheme-like heterojunction that facilitates electron migration to the ZnS conduction band while retaining ZnO valence band holes for oxidation. Scavenging experiments confirmed that electrons dominate MB degradation (k_app up to 185.1 × 10⁻³ min⁻¹ with EDTA/t-BuOH/Ar), outperforming hole-mediated pathways. Antibacterial assays against Staphylococcus aureus revealed good antimicrobial activity for all nanoparticles. The nanocomposite’s antibacterial activity was similar across all samples and was only slightly lower than that of pure ZnS and ZnO. Full article

This study presents the development of a low-cost H₂ gas sensor made from a titanium dioxide–zinc oxide composite by means of a simple, cost-effective screen-printing method. The sensing material was created by mixing titanium dioxide and zinc oxide nanoparticles with an organic binder, which was screen-printed onto a glass substrate containing silver electrodes. These samples were then characterized using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The XRD results confirmed that the films boasted well-defined crystallinity, with predominant anatase and hexagonal ZnO phases, as well as uniformity of grains. Sensor performance was evaluated in a custom-built chamber at hydrogen concentrations of 100 to 1000 ppm and at operating temperatures of 100 °C, 200 °C, and 300 °C. The results indicate improved sensor performance as the operating temperature increased to 300 °C, with the best sensitivity values of 0.99, 1.17, and 1.31 at hydrogen concentrations of 100, 500, and 1000 ppm, respectively. The sensor showed stable and reproducible response characteristics, and its responses were retimed after a few hundred seconds. Low-cost fabrication, ease of processing, and reliable sensor performance make titanium oxide–zinc oxide composites promising candidates for hydrogen detection. Full article

A thorough understanding of the microbial ecology of meat products, dominated by critical pathogens such as Salmonella spp., Campylobacter jejuni, Escherichia coli, and Listeria monocytogenes, and marked by risks of resistant biofilm formation and vulnerabilities specific to informal commercial sectors, underscores the need to transition from conventional inert barriers to active nanostructured packaging systems. This review critically analyses the current state of antimicrobial nanomaterials, dissecting their molecular mechanisms of action and dynamic interactions designed to preserve sensory and nutritional food quality. Beyond technical effectiveness, the paper highlights the inherent tension between technological innovation and toxicological uncertainties, addressing major challenges related to migration kinetics in complex lipid matrices and the uneven global regulatory landscape. Main limitations of frequently investigated materials, along with regulatory discrepancies among international authorities and safety variables, are discussed to contextualise the current barriers to industrial implementation. We conclude that although nanotechnology represents a transformative force for extending shelf life, safety validation through rigorous assessment of migration remains imperative to harmonise scientific progress with public health protection. This integrative perspective highlights the imperative of calibrating nanostructural architecture to the bioactive profile, providing strategic design directions essential for the sustainable translation of experimental innovation to industrial scale. Full article

The removal of cadmium from contaminated water remains a critical challenge due to its high toxicity, persistence, and limited treatability at low concentrations. In this study, we propose a novel algal–nanoparticle system that integrates cadmium adsorption by Chlorella vulgaris with zinc ferrite (ZnFe₂O₄) nanoparticle-assisted sedimentation, with the aim of addressing a significant operational challenge in algal remediation. The microalgal biomass demonstrated the capacity to remove cadmium with efficiencies exceeding 90%, facilitated by adsorption through surface functional groups. The incorporation of ZnFe₂O₄ nanoparticles promoted the formation of dense, magnetically responsive aggregates, significantly accelerating biomass settling without the necessity for additional chemical flocculants. The strategy’s efficacy is evidenced by its enhancement of metal removal and solid–liquid separation processes, which renders it a potentially scalable and environmentally sustainable approach for the treatment of cadmium-contaminated wastewater. The strategy holds relevance for effluents derived from mining, electroplating, fertilizer production and battery manufacturing. Full article

Polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) blend nanocomposites reinforced with plasma-assisted synthesized zinc oxide–gold (ZnO–Au) nanoparticles were prepared via casting at varying nanoparticle concentrations. Structural and interfacial modifications were analyzed using XRD, FTIR, Raman spectroscopy, and XPS. XRD analysis confirmed the nanocomposite crystallinity, showing an average crystallite size of 24.48 nm and a lattice strain of 4.32 × 10⁻³ for the 0.15 wt% ZnO–Au composite. FTIR and Raman spectra revealed band shifts and broadening, indicating strong interactions between ZnO–AuNPs and the polymer matrix. XPS analysis further verified Zn and Au incorporation and changes in C 1s and O 1s intensities, reflecting modified surface chemistry. Optical analysis revealed a reduction in the band gap from 4.60 eV (pure PVA/CMC) to 3.52 eV for the 0.15 wt% ZnO–Au nanocomposite, accompanied by an increase in refractive index from 2.058 to 2.244, along with enhanced UV-shielding the performance due to reduced UV transmittance and increased film opacity. Thermogravimetric analysis demonstrated enhanced thermal stability, while antibacterial tests against E. coli and S. aureus confirmed strong antimicrobial activity. These findings demonstrate that PVA/CMC/ZnO–Au nanocomposites are a promising candidate for antibacterial, UV-blocking, food packaging, and optoelectronic applications. Full article

The adaptive nature of bacteria and their increasing resistance to conventional therapies demand alternative strategies to effectively control wound infections. At the wound site, dynamic biological processes are easily disrupted by microbial colonization, compromising normal healing. In this study, Zn-based nanoparticles composed of zinc oxide (ZnO) and zinc phosphate (Zn₃(PO₄)₂) were synthesized via a green route using coconut milk and coconut water as biological media. Although ZnO formation via zinc hydroxide intermediates was initially targeted, structural analyses revealed a multiphase Zn-based system resulting from interactions between Zn²⁺ ions and naturally occurring phosphate species in the coconut-derived sources. The resulting material was incorporated into sodium alginate/poly(vinyl alcohol) hydrogel dressings, further enhanced with spirulina and aronia powders. Physicochemical characterization (XRD, SEM, EDS, FTIR), along with swelling and degradation studies, confirmed structural stability and appropriate hydrogel behavior. Antimicrobial testing against Staphylococcus aureus and Escherichia coli demonstrated a dominant antibiofilm effect of the Zn-based nanoparticles, while botanical additives exhibited moderate, time-dependent activity. Biological evaluation demonstrated good cytocompatibility toward human keratinocytes and murine macrophages, with botanical additives mitigating mild nanoparticle-induced cellular responses. Full article

Mesoporous bioactive glass nanoparticles (MBGNs) are promising for bone tissue engineering; however, surgical site infection and oxidative stress often compromise regeneration. To address this, MBGNs co-doped with cerium (Ce), zinc (Zn), and strontium (Sr) were synthesized using a microemulsion-assisted sol-gel route (xCe-yZn-Sr-MBGNs; x = 0, 1, 2; y = 0, 0.5, 1). The resulting spherical nanoparticles (150–200 nm) exhibited a mesoporous structure with a specific surface area of (~340–425 m²/g), sustained ion release, and apatite formation in simulated body fluid. In vitro evaluations with MC3T3-E1 pre-osteoblasts demonstrated dose-dependent cytocompatibility, specifically in the co-doped formulations; however, higher Ce concentrations (2Ce-yZn-Sr-MBGNs) reduced viability following prolonged exposure. Crucially, the 1Ce-1Zn-Sr-MBGNs significantly enhanced osteogenic differentiation, as evidenced by a two-fold increase in osteogenic marker gene expression and a ~45% increase in calcium mineral deposition compared to undoped MBGNs within 14 days. Moreover, these particles accelerated cell migration, achieving ~70% scratch-wound closure within 24 h. Furthermore, 1Ce-1Zn-Sr-MBGNs displayed strong radical scavenging capacity and potent antibacterial activity against S. aureus and P. aeruginosa. These findings indicated that 1Ce-1Zn-Sr-MBGNs exhibited multiple therapeutic effects, including antibacterial, radical-scavenging, and osteogenic effects. By optimizing dopant ratios, these multifunctional nanomaterials emerge as promising candidates for next-generation bone grafts or implant coatings. Within the scope of this study, they demonstrated the capacity to simultaneously address three critical challenges in bone healing: controlling infection, mitigating oxidative stress, and promoting mineralized tissue formation. While these in vitro results provide a robust foundation, further in vivo validation is warranted to confirm their efficacy within complex physiological environments. Full article