Search Results (1,122)

Background/Objectives: Silver’s ability to kill pathogenic bacteria is being widely researched in environment, consumer, and health-related applications. One topic of voluminous research is the antimicrobial properties of silver and silver in wound dressings. This research literature has been reviewed in articles using qualitative analyses, meta-analyses, systematic reviews, bibliometric analyses, and other grounded methods. We present a new strategy for the analysis of the population of articles on the subject based on an ontology of this topic. Methods: A search of the Scopus database for all peer-reviewed articles on silver in wound dressings yielded a population of 4711 relevant ones. The ontology is a logical deconstruction of the problem: “use of silver species on nanosupports deposited on a matrix with antimicrobial effectiveness assayed by methods to promote wound healing of chronic wounds as determined by recovery”. Each bolded term denotes a dimension of the ontology, and each dimension denotes a taxonomy of constituent elements. A Convolutional Neural Network (CNN) was trained using a manually mapped subset of articles. The CNN was then used to map the population of articles. Results: Out of the 4711 articles, 3079 dealt with silver and wound dressings; the others involved silver, but were not related to wound dressings and were not considered. Overall analysis shows that three classes of silver encompass the entire field: silver nanoparticles (AgNP) (78% of papers), inorganic silver-ion-containing species (7%) and silver associated with organic molecules (15%). AgNP papers have grown exponentially beginning in the early 2000s; there is no clear trend regarding inorganic silver-containing-species papers; whereas with the silver-organics species papers, there has been growth in the past decades, but now the number of publications is stabilizing. Research on the AgNPs has primarily focused on in vitro testing (54%), with very limited animal testing (17%) and human testing (3%). On the other hand, with silver-organics, animal (30%) and human testing (38%) are prominent. Inorganic silver ion species also have been human-tested extensively (43%). Thus, in clinical applications of silver wound dressings, AgNP lags considerably as compared to the other silver species, though academic research in AgNP is robust. Conclusions: From detailed temporal visualizations of the ontological mapping, the antecedents and consequences of silver in wound dressings are presented. This first ontological analysis is a novel way of visualizing an entire research field and the temporal characteristics of the various dimensions of the ontology provide information on the current state of research as well as where the field is headed. Full article

This article presents the results of the development of an antibacterial coating based on polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) fibers with embedded silver nanoparticles. Silver nanoparticles were synthesized via the use of PEG, which acts as a reducing agent for Ag⁺ ions and a stabilizer for the colloidal system. The resulting sols were pink, dark purple, and orange color. The viscosity of the compositions, which increased with increasing PEG and AgNO₃ concentrations, was studied. The sizes of the synthesized silver nanoparticles were determined via dynamic light scattering. For all compositions, monomodal particle size distributions were obtained with characteristic sizes of 50.75, 58.73, 13.54 and 28.21 nm. The highest ζ-potential value for the silver nanoparticles was ‒15.5 mV, indicating their stability. The electrical conductivity of the compositions increased with increasing molar concentration of AgNO₃. The resulting PVP-PEG compositions with silver nanoparticles demonstrated resistance to pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. A portable electrospinning device was developed at the Mendeleev University of Chemical Technology of Russia to apply the compositions to the skin and form a protective coating of PVP-PEG fibers with an antibacterial effect. Fiber formation was confirmed by scanning electron microscopy. The incorporation of silver into the fiber structure was confirmed by the results of elemental analysis and surface mapping of the samples. Full article

Background/Objectives: Endophytic fungi represent an alternative source for resveratrol (RES) production. The present study aims to utilize mycoendophytic-derived resveratrol as a reducing agent for the synthesis of silver nanoparticles (AgNPs), in addition to further assay the cytotoxic activity of a RES-conjugated nanocarrier system toward human epidermoid carcinoma A-431 cells. Methods: Alternaria alternata AUMC 16209 was isolated from the stem of grapevine Vitis vinifera L. cultivar prime. Strain identification was achieved through morphological and molecular characterization using ITS sequencing. A. alternata AUMC 16209 exhibited RES production capability upon cultivation on PDB medium for seven days with a total of 8.25 mg/L as determined by HPLC. The crude RES was purified using flash chromatography followed by structure elucidation through ¹H and ¹³C NMR analyses. The purified RES was used for green synthesis of nanoparticles, acting as a reducing agent for silver ions. Results: Stable RES-AgNPs were fabricated at particle sizes ranging from 25 to 47 nm. RES-AgNPs observed a plasmon resonance absorption band at 415 nm with a negative zeta potential value of −38.5 mV. The crystalline structure of RES-AgNPs was addressed through X-ray diffraction analysis. FT-IR spectroscopy confirms the involvement of the functional –OH group and the aromatic C=C bond in the reduction and stabilization process. RES-AgNPs was more efficient to inhibit the cellular proliferation of human epidermoid carcinoma A-431 cells compared to RES alone. Conclusions: This report introduces for the first time an endophytic A. alternata as a sustainable source for RES production and emphasizes its potential for green synthesis of stable AgNPs with promising cytotoxic activity. Full article

In this paper, we utilized sodium titanate as a substrate to fabricate a supported antifungal repair agent capable of inhibiting fungi through the release of silver ions, and applied it to the preservation and restoration of wooden materials. The structural and material properties of sodium titanate were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and adsorption kinetic modeling. Furthermore, its effectiveness in wood restoration as well as its antifungal performance were evaluated. Results indicate that the synthesized sodium titanate exhibits a distinctive tubular structure, with a diameter of approximately 12 nm, a pore size of 7 nm, and a specific surface area as high as 310.91 m²/g. The abundant ion exchange active sites on the material surface provide conditions for the loading of silver ions. At 25 °C, the maximum adsorption capacity for silver ions reaches 515.5 mg/g, with an adsorption amount accounting for 34.0 wt.%. When combined with polyvinyl alcohol (PVA) for reinforcing wooden materials, it significantly increases the packing density of the reinforcing agent, ultimately enhancing the compressive strength of wood from 155.0 MPa to 412.2 MPa. Furthermore, owing to the antifungal effect of silver ions, the treated wood demonstrates effective resistance against the growth of Aspergillus niger. Full article

The use of nanoparticles (NPs) synthesized from plant extracts is an alternative to conventional pesticides for the control of agricultural pests. This study aimed to optimize the conditions of synthesis of silver–zinc nanoparticles (Ag-ZnNPs) using extracts of Ocimum basilicum L. and Crotalaria longirostrata Hook. & Arn. and to evaluate their phytotoxic impact on maize seedlings. The Ag-ZnNPs (Ag-Zn nanoparticles) were synthesized by redox reaction between metal ions and reducing metabolites present in the extracts. A response surface methodology (RSM) with three factors (extract concentration, heating time and pressure) was applied to determine the optimal synthesis conditions. The phytotoxicity of nanoparticles (NPs) on maize seedlings was subsequently evaluated on root growth, oxidative stress enzymes (CAT, POD, and APX), and physiology of seedlings. Nanoparticles synthesized from C. longirostrata extract demonstrated superior properties, with an optimization of synthesis (R² = 95.3%) where the extract concentration (1:4 v/v; p < 0.01) was the critical factor influencing the reduction of metallic ions to nanoparticles. These NPs exhibited superior stability, smaller size (<100 nm), and zeta potential greater than 30 mV compared with O. basilicum extracts. Their NPs exhibited poorer optimization of synthesis (R² = 43.8%) without the effect of any of the variables evaluated. Essentially, C. longirostrata NPs showed no phytotoxic effects on maize seedlings’ physiological parameters and enhanced root growth (117.2 mm) without negatively affecting photosynthesis (PSII 70-81 FvFm). Ag-ZnNPs synthesized with C. longirostrata exhibited optimal stability and size, along with no observed possible phytotoxicity effects, unlike O. basilicum NPs, which cause stress on maize seedlings. Therefore, Crotalaria longirostrata NPs could represent a promising material for agricultural pest control, with no apparent adverse effect on maize crops. Full article

To address the inherent low voltage and poor energy density of LiFePO₄, LiFe_0.6Mn_0.4PO₄ (LFMP) has emerged as a promising cathode for next-generation lithium-ion batteries. However, its practical application is severely hindered by intrinsic limitations such as low electronic conductivity and sluggish Li⁺ diffusion. To address these challenges, this study investigates the effects of silver (Ag) doping on the structural and electrochemical performance of LFMP. Through a facile high-temperature solid-state approach, Ag⁺ ions are successfully incorporated into the LFMP matrix, and the resulting material (LFMP-Ag) is systematically characterized. The results reveal that partial Ag is doped into the LFMP lattice while an Ag-rich secondary phase within LFMP particles is detected, significantly enhancing the charge transfer kinetics. The Ag-doped LFMP cathodes exhibit superior discharge capacity of 142.1 mAh g⁻¹ at 0.1 C, enhanced rate capability, better cyclic stability (92.3% retention after 300 cycles) and enhanced thermal stability, surpassing the undoped LFMP counterparts. These findings demonstrate that Ag doping is an effective strategy for optimizing the electrochemical performance of LFMP cathodes, offering a viable pathway toward advanced battery technologies. Full article

Although chronic contamination by silver ions (Ag⁺) can persist in aquatic systems over long periods of time and can therefore have an impact on population developments, regulatory testing commonly relies on single-generation endpoints. Here, we used Daphnia magna to quantify long-term effects of pg/L to ng/L concentrations of Ag⁺ across generations and to test whether recovery depends on exposure history. Using 21 d life-cycle assays over up to seven consecutive generations, we quantified survival, key life-history traits, and population fitness (intrinsic rate of natural increase, r). In our study, low environmental concentrations of Ag⁺ caused minimal mortality, but sublethal effects persisted or multiplied over generations. Notably, continuous exposure led to significant reductions in body length and r at 50 pg/L (nominal LOEC) by the fourth generation exposed, representing population-relevant effects of Ag⁺ at very low concentrations which should be given consideration in the assessment of both water quality and the chemical itself. Recovery was concentration-dependent: low-concentration-exposed lineages recovered within a few generations, whereas 15 ng/L exposure resulted in persistent deficits even through the recovery period of three generations. Exposure-history patterns indicated that long-term outcomes were dominated by the cumulative number of exposed generations. These findings highlight the limitations of acute and single-generation assays and emphasize the importance of considering information on the effects of chemicals, including Ag⁺, across multiple generations in risk assessments. They also highlight the need to include expectations regarding recovery after the removal of pollutants in these assessments. Full article

Environmental pollution affects the health of living organisms, provoking the emergence of new diseases and infections. In search of sustainable and effective solutions, this study presents a “green” synthesis of five silver nanocomposites with activated carbon (Ag-NACs) obtained from waste biomass from peach shells. The process is carried out in an aqueous environment and does not use toxic organic solvents. The chemical composition, structural properties and morphology of the synthesized Ag-NACs were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). Comparative analysis under different conditions, including silver concentration (0.5%, 1.5%, 4.0% and 8.0%) and impregnation time (24 and 72 h), identified the samples with 4.0% and 8.0% Ag as optimally structured, showing the strongest antibacterial activity. The results confirmed the synergistic effect and mechanism of the carbon composites, which effectively attract bacterial cells while the silver ions inhibit the growth of various pathogens. This efficacy was demonstrated against both Gram-positive (Gram⁺), Bacillus subtilis, Bacillus spizizenii, Staphylococcus aureus, Listeria innocua, and Enterococcus faecium, and Gram-negative (Gram⁻) bacterial strains, Escherichia coli, Salmonella typhimurium, Salmonella enteritidis, and Stenotrophomonas maltophilia, which highlights the significant potential of Ag-NACs. Full article

Objectives: In dental implantology, the priorities in scientific research are to identify solutions that guarantee a beneficial biomaterial–tissue interaction, both in terms of implant biointegration and protection against infections. The experimental approach consisted of chemical deposition of silver (Ag), silver and hydroxyapatite (HAP) on a TiZr metallic support. The aim of the research is to study the influence of hydroxyapatite on the possible adverse effects produced by silver in antibacterial coatings. Methods: The characterization of the coating was performed by scanning electron microscopy (SEM) and EDS spectroscopy, XRD diffraction and FT-IR infrared analysis. In vitro cell viability and adhesion testing was performed by quantitative (MTT) and qualitative fluorescence-based assays on samples (without deposition and with chemical deposition), in the presence of human fetal osteoblasts (hFOB cell line) after 8 days of incubation. Results: The findings of the study indicate an increase in cell viability by combining silver with hydroxyapatite. Preliminary data indicated a cell viability of 20% when the metal support is coated exclusively with silver and 60% in the presence of hydroxyapatite in the silver coating. Conclusions: The experimental study offers insights into the potential cytotoxic effects of silver in antibacterial coatings. Co-deposition with hydroxyapatite improved osteoblast viability compared to surfaces coated with silver alone, indicating that it may have a beneficial effect in Ag-based surface functionalization. The underlying mechanism (e.g., modulation of silver species/ion release) was not directly quantified in this work and should be addressed in future studies. Full article

Fluorescent metal nanoclusters show great promise in heavy metal ion sensing. Herein, a bimetallic nanocluster (GSH-Au/Ag NCs) with orange fluorescence was synthesized through a facile one-pot method. The synthesized GSH-Au/Ag NCs displayed optimal excitation and emission peaks at 275 and 610 nm, respectively. The incorporation of silver can enhance the fluorescence of metal nanoclusters. The fluorescence of as-synthesized GSH-Au/Ag NCs can be significantly quenched by Hg²⁺ and Cu²⁺, and a “on–off” fluorescent probe was designed. The detection conditions, including pH and the concentration of the probe, were optimized. The respective detection limits for Hg²⁺ and Cu²⁺ ions under optimal detection conditions are estimated to be 40 nM and 33 nM, over the linear range of 100–1200 nM. Furthermore, a ratiometric fluorescent probe was prepared by mixing quinine sulfate and as-synthesized GSH-Au/Ag NCs. Hg²⁺ and Cu²⁺ can effectively quench the red fluorescence of GSH-Au/Ag NCs, whereas the blue fluorescence of quinine sulfate remains invariant. This leads to measurable changes in the RGB values of the resulting fluorescence images. The ratio (R/B) exhibits a linear relationship with the concentration of Hg²⁺ and Cu²⁺, enabling the determination of its concentration by analyzing RGB values in fluorescence images. This visual detection method significantly reduces both assay time and cost, making it suitable for on-site detection of heavy metal ions in water samples. Full article

Ionic polymer–metal composites consist of an ion-conducting polymer–gel membrane sandwiched between two flexible electrodes, representing a class of soft electroactive materials capable of large deformation under low voltage. The gel membrane, swollen with solvent, facilitates ion migration under an electric field, enabling actuation. Tailoring the interfacial architecture between the electrode and the polymer–gel membrane is pivotal for advancing high-performance IPMC actuators. This study presents a comparative investigation of three core–shell nanocomposite electrodes, fabricated via in situ polymerization, for IPMC applications. Among these, the polyaniline-coated multi-walled carbon nanotube composite exhibits a deliberately designed hierarchical structure, with a specific surface area of 32.345 m²·g⁻¹ and a conductive doped polyaniline shell, as confirmed through XPS analysis. This optimized interface enables superior charge storage and transport, endowing the corresponding electrode with a specific capacitance of 40.28 mF·cm⁻² at 100 mV·s⁻¹—3.2 times greater than that of conventional silver-based electrodes—along with a reduced sheet resistance. When integrated with a Nafion ion–gel membrane, the PANI@MWCNT electrode achieves a 67% increase in force density and a larger displacement output compared to standard devices, directly correlated with its enhanced electrical and electrochemical properties. This work highlights the critical role of core–shell interfacial engineering in governing electromechanical performance at the electrode–gel interface and offers a practical design strategy for developing high-performance, cost-effective IPMC actuators for soft robotics, flexible electronics, and related applications. Full article

Ion-selective electrodes (ISEs) are widely used analytical tools for the determination of specific ions in a variety of analytical applications due to their simplicity, selectivity, and low cost. Recent developments in materials science and digital fabrication have opened new opportunities for redesigning ISEs using modern manufacturing techniques. Here, we present a new application of 3D printing for fabricating potassium-selective electrodes using a simplified membrane composition. The 3D printing cocktail was prepared by mixing potassium tetraphenylborate, silver sulfide or graphite, and industrial ABS (acrylonitrile Butadiene Styrene) polymer. Membranes were tested both without and with the addition of ZnO nanoparticles. Incorporation of ZnO NPs significantly enhanced the electrode slope, while graphite-based membranes exhibited faster response, with potential stabilizing within 3–7 s across a concentration range of 4.88 × 10⁻⁵ mol L⁻¹ to 1.00 × 10⁻² mol L⁻¹. The optimized 3D printed membrane containing 0.6% ZnO NPs showed near-Nernstian behaviour (slope: 59.178 mV per decade and R² = 0.9989), a limit of detection of 2.06 × 10⁻⁵ mol L⁻¹ and high selectivity against common interfering ions. These results demonstrate that 3D printing combined with a suitable membrane composition and nanoparticle incorporation provides a versatile platform for rapid, reproducible, and high-performance potassium ISEs. Full article

Photo-thermo-refractive (PTR) glass is a key material for optical devices, yet the synergistic mechanism between its raw material precursors remains unclear. This study systematically investigates the individual and combined effects of silver precursors (Ag₂O and AgNO₃) and sodium salts (Na₂CO₃ and NaNO₃) on the structural evolution and crystallization behavior of Si-Na-Al-Zn-based PTR glasses. Through a combination of spectroscopic (UV-Vis, FTIR, Raman), thermal (DSC), and microscopic (SEM) characterizations, we demonstrate that the precursor combination profoundly influences the glass network homogeneity, ion mobility, and phase separation behavior. The results reveal that the AgNO₃ and NaNO₃ combination fosters a highly homogeneous and thermally stable network, facilitating the formation of a uniform distribution of silver nanoparticles and, subsequently, a dense nanoscale precipitation of NaF crystals. This work elucidates the critical synergistic mechanism between precursors, providing a fundamental basis for the precise composition design of high-performance PTR glasses for advanced optical applications. Full article

This study reports the precise synthesis of red-emitting gold–silver bimetallic nanoclusters (Au-AgNCs) via a one-pot hydrothermal method using thiolactic acid as both the ligand and reducing agent. The Au-AgNCs possess an average diameter of 1.85 nm and exhibit strong fluorescence emission at 687 nm. Furthermore, they display notable assembly-induced emission enhancement (AIEE) properties. Upon assembly with bovine serum albumin (BSA), their fluorescence quantum yield significantly increases from 2.50% to 7.78%. Then Au-AgNCs@BSA assembly was employed as a ratiometric fluorescence sensor for the detection of chlortetracycline (CTC). In the presence of CTC, the original red emission of the assembly at 687 nm remained stable, while a new blue emission emerged at 420 nm and intensified progressively with CTC concentration. The ratio of the two emission intensities (I₄₂₀/I₆₈₇) exhibited an excellent linear correlation with CTC concentration over the range of 0.10 to 15 μM, with a limit of detection (LOD) of 20 nM. Notably, the sensor demonstrated exceptional selectivity for CTC, showing negligible response to common interfering substances such as metal ions, anions, amino acids, and crucially, other tetracycline antibiotics (tetracycline, oxytetracycline, and doxycycline). The practical applicability of the sensor was validated through the determination of spiked CTC in real water samples, achieving satisfactory recovery rates. In conclusion, this work accomplishes two key objectives: the development of novel AIEE-active Au-Ag bimetallic nanoclusters and the design of an efficient ratiometric sensing strategy. This approach enables the highly selective and sensitive detection of CTC, offering a promising tool for environmental monitoring. Full article

The green synthesis of nanomaterials using biological resources has emerged as a sustainable alternative to conventional chemical routes. In this study, the wild ectomycorrhizal mushroom Russula sanguinea (Rs) was employed as a natural reducing and stabilizing agent for the biosynthesis of silver-decorated zinc-based nanostructures (Ag–ZnNSs/Rs). The formation and physicochemical properties of the nanostructures were systematically characterized using UV–Vis spectroscopy, FT-IR spectroscopy, SEM, TEM, and EDX analysis. Transmission electron microscopy revealed predominantly spherical nanoparticles with good dispersion, and quantitative analysis of 227 individual particles demonstrated an average diameter of 19.36 ± 7.89 nm (range: 10.92–61.00 nm). FT-IR analysis confirmed the involvement of fungal biomolecules in metal ion reduction and surface stabilization, indicating effective bio-capping of the nanostructures. The biofunctional performance of the biosynthesized Ag–ZnNSs/Rs was evaluated through antioxidant and antimicrobial assays. Compared to the crude mushroom extract, the nanostructures exhibited significantly enhanced 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity with an IC₅₀ value of 7.29 ± 0.10 mg mL⁻¹ compared to 13.66 ± 0.15 mg mL⁻¹ for the crude extract. In addition, notable antimicrobial activity was observed against representative Gram-positive and Gram-negative bacteria (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) as well as the yeast Candida albicans. Overall, this study demonstrates that Russula sanguinea is an effective biological platform for the green synthesis of silver-decorated zinc-based nanostructures with improved biofunctional properties, highlighting the potential of wild mushrooms as underexplored resources in sustainable nanomaterial development. Full article