Search Results (355)

This study evaluated the antimicrobial efficacy of cefiderocol and various forms of silver (ionic and nanoparticulate) as potential components of wound-dressing reagents against both reference and multidrug-resistant (MDR) Gram-negative bacteria. The anticipated synergistic effect between cefiderocol and nanosilver was not consistently observed; in fact, for reference strains, the combination was less effective than cefiderocol alone. However, in MDR and cefiderocol-resistant A. baumannii strains, combining both agents enhanced antibacterial efficacy. Notably, the effectiveness of silver did not increase with concentration, and low or medium nanosilver concentrations were often more effective. Mechanistically, high concentrations of silver may antagonize cefiderocol’s action by inhibiting bacterial surface proteins involved in siderophore-mediated uptake. Generalized linear modeling confirmed that the strain type, silver form, concentration, and their interactions significantly influenced inhibition zones. These findings highlight the importance of agent selection, concentration, and formulation in designing effective antimicrobial wound dressings. They also suggest that further research is needed to optimize such combination therapies for clinical use. Full article

Marine algae offer environmentally friendly platforms for green nanoparticle synthesis. This study reports the biosynthesis of silver nanoparticles using polysaccharides isolated from the brown alga Chnoospora minima (PAgNPs) and evaluates their therapeutic potential. Fourier Transform Infrared Spectroscopy (FTIR) confirmed algal polysaccharide functional groups. Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis characterized the nanoparticles as spherical (~84 nm average size), stable (zeta potential −18.5 mV), and containing elemental silver without nitrogen. The PAgNPs exhibited potent antioxidant activity (~100% DPPH scavenging) and significant antimicrobial efficacy, particularly against Staphylococcus aureus and Candida species. Crucially, PAgNPs displayed potent antiproliferative activity against human lung cancer cells (A549, IC₅₀: 13.59 µg/mL). In contrast, toxicity to normal Vero cells was significantly lower (IC₅₀: 300.2 µg/mL), demonstrating notable cancer cell selectivity (SI 22.1). Moderate activity was observed against MCF-7 breast cancer cells (IC₅₀: 100.7 µg/mL). These results demonstrate that C. minima polysaccharide facilitates the synthesis of biocompatible AgNPs with promising antimicrobial and selective anticancer capabilities, highlighting their potential for further development as nanotherapeutics. Full article

We present a simple method for customizing the optical characteristics of gold-core, silver-shell (Au@Ag) nanoparticles through controlled morphosynthesis via a seed-mediated chemical reduction approach. By systematically adjusting the concentration of cetyltrimethylammonium chloride (CTAC), we obtained precise control over both the thickness of the Ag shell and the particle shape, transitioning from spherical nanoparticles to distinctly defined nanocubes. Bright field and high-angle annular dark-field scanning transmission electron microscopy (BF-STEM and HAADF-STEM), and energy-dispersive X-ray spectroscopy (EDS) were employed to validate the structural and compositional changes. To link morphology with optical behavior, we utilized the Mie and Maxwell–Garnett theoretical models to simulate the dielectric response of the core–shell nanostructures, showing trends that align with experimental UV-visible absorption spectra. This research presents an easy and adjustable method for modifying the plasmonic properties of Ag@Au nanoparticles by varying their shape and shell, offering opportunities for advanced applications in sensing, photonics, and nanophotonics. Full article

Silver nanoparticles (AgNPs), lauded for their unique antibacterial and physicochemical attributes, are proliferating across industrial sectors, raising concerns about their environmental fate, in aquatic systems. While “green” synthesis offers a sustainable production route with reduced chemical byproducts, the safety of these AgNPs for aquatic fauna remains uncertain due to nanoparticle-specific effects. Conversely, mast cells play crucial roles in fish immunity, orchestrating innate and adaptive immune responses by releasing diverse mediators and recognizing danger signals. Goblet cells are vital for mucosal immunity and engaging in immune surveillance, regulation, and microbiota interactions. The interplay between these two cell types is critical for maintaining mucosal homeostasis, is central to defending against fish diseases and is highly responsive to environmental cues. This study investigates the acute dermatotoxicity of environmentally relevant AgNP concentrations (0, 0.031, 0.250, and 5.000 μg/L) on zebrafish epidermis. A 96 h assay revealed a biphasic response: initial mucin hypersecretion at lower AgNP levels, suggesting an early stress response, followed by a concentration-dependent collapse of mucosal integrity at higher exposures, with mucus degradation and alarm cell depletion. A rapid and generalized increase in epidermal mucus production was observed across all AgNP exposure groups within two hours of exposure. Further mechanistic insights into AgNP-induced toxicity were revealed by concentration-dependent alterations in goblet cell dynamics. Lower AgNP concentrations initially led to an increase in both goblet cell number and size. However, at the highest concentration, this trend reversed, with a significant decrease in goblet cell numbers and size evident between 48 and 96 h post-exposure. The simultaneous presence of neutral and acidic mucins indicates a dynamic epidermal response suggesting a primary physical barrier function, with acidic mucins specifically upregulated early on to enhance mucus viscosity, trap AgNPs, and inhibit pathogen invasion, a clear defense mechanism. The subsequent reduction in mucin-producing cells at higher concentrations signifies a critical breakdown of this protective strategy, leaving the epidermis highly vulnerable to damage and secondary infections. These findings highlight the vulnerability of fish epidermal defenses to AgNP contamination, which can potentially compromise osmoregulation and increase susceptibility to threats. Further mechanistic research is crucial to understand AgNP-induced epithelial damage to guide sustainable nanotechnology. Full article

The purpose of current study was the green synthesis of bioactive silver nanoparticles (AgNPs) using Brevibacillus sp. MAHUQ-41 and the exploration of their role in controlling drug-resistant bacterial pathogens Listeria monocytogenes and Yersinia enterocolitica. The culture supernatant of strain MAHUQ-41 was employed for a simple and eco-friendly synthesis of biofunctional silver nanoparticles (AgNPs). The resulting nanoparticles were analyzed using several techniques, including UV–Visible spectroscopy, XRD, FE-TEM, FTIR, and DLS. The UV–Vis spectral analysis of the AgNPs synthesized via Brevibacillus sp. MAHUQ-41 revealed a prominent absorption peak at 400 nm. FE-TEM results confirmed spherical-shaped 15–60 nm sized nanoparticles. XRD results indicated that the synthesized AgNPs were crystalline in nature. The FTIR spectrum determined various functional groups on the surface of synthesized nanoparticles. Potent antibacterial properties were observed in green-synthesized AgNPs against tested pathogens. The MIC value of extracellular synthesized AgNPs for both pathogenic bacteria was 6.2 µg/mL, and the MBCs were 25.0 µg/mL and 12.5 µg/mL for L. monocytogenes and Y. enterocolitica, respectively. Treatment by synthesized AgNPs resulted in morphological alterations and structural damages in both L. monocytogenes and Y. enterocolitica. These alterations can interfere with regular cellular activities, potentially resulting in cell death. This study is the first to report the antimicrobial properties of silver nanoparticles synthesized using Brevibacillus sp. MAHUQ-41. The findings obtained in the present study supported the role of Brevibacillus sp. MAHUQ-41-mediated synthesized AgNPs in controlling drug-resistant bacterial pathogens L. monocytogenes and Y. enterocolitica. Full article

The effective healing of chronic wounds requires balancing antimicrobial activity with tissue regeneration. In this study, we developed a novel, eco-friendly synthesis method using Artemisia argyi extract to produce silver nanoparticles (AgNPs), addressing toxicity concerns associated with conventional chemical synthesis methods. Through optimization of multiple synthesis parameters, monodisperse spherical AgNPs with an average diameter of 6.76 ± 0.27 nm were successfully obtained. Plant-derived compounds from Artemisia argyi extract acted as efficient mediators for both reduction and stabilization, yielding nanoparticles with high crystallinity. The synthesized AgNPs exhibited potent antibacterial activity against both Gram-negative and Gram-positive bacteria, with minimum inhibitory concentrations of 8 μg/mL against Escherichia coli and 32 μg/mL against Staphylococcus aureus, while maintaining high biocompatibility with L929 fibroblasts at concentrations ≤ 8 μg/mL. When integrated into polylactic acid/collagen type I (PLA/Col1) nanofibrous matrices, the optimized 0.03% AgNPs/PLA/Col1 dressing significantly accelerated wound healing in a diabetic rat model, achieving 94.62 ± 2.64% wound closure by day 14 compared to 65.81 ± 1.80% observed in untreated controls. Histological analyses revealed a dual-functional mechanism wherein controlled silver ion release provided sustained antibacterial protection, while concurrently promoting tissue regeneration characterized by enhanced collagen deposition, reduced inflammation, and increased neovascularization. This innovative approach effectively addresses critical challenges in diabetic wound care by providing simultaneous antimicrobial and regenerative functions within a single biomaterial platform. Full article

Green synthesis of silver nanoparticles (AgNPs) using plant extracts has emerged as a sustainable and eco-friendly alternative to conventional physical and chemical methods. This review provides a comprehensive overview of plant-mediated synthesis routes, emphasizing the influence of phytochemicals on nanoparticle formation, morphology, and stability. The physicochemical properties of AgNPs, such as size, shape, and surface characteristics, are critically examined in relation to synthesis parameters, summarizing the plant species employed and associated reaction conditions. The wide-ranging applications of plant-based AgNPs are explored, including antimicrobial, agricultural, environmental, industrial, and biomedical uses, such as drug delivery and wound healing. The section is supported with recent application-specific studies to their corresponding nanoparticle properties, highlighting the relationship between structure and function. Finally, this review discusses current challenges, particularly potential toxicity considerations, and outlines future perspectives for standardization, mechanistic understanding, and translational potential in wide-ranging applications. Full article

The therapeutic use of silver nanoparticles (AgNPs) has been increasing, especially in phototherapy strategies. The plasmonic properties of AgNPs have contributed to their excellent results as phototherapeutic agents, namely for photodynamic therapy (PDT), photothermal therapy (PTT), and photodynamic inactivation of microorganisms. Moreover, the capacity of these nanostructures to release silver ions (Ag⁺) and enhance the production of reactive oxygen species (ROS) has been explored in combination with light to treat several diseases. Moreover, synthesis, functionalization, and conjugation strategies with targeting agents have been widely studied to optimize selectivity and maximize the therapeutic efficacy of these nanoplatforms. In this work, we reviewed the recent advancements (2019–2024) in the use of AgNPs for phototherapy applications, with an emphasis on evaluating therapeutic efficacy and specific targeting. According to the literature, in oncology, AgNPs have been predominately employed in PTT-based strategies, demonstrating significant tumor cell death and preservation of healthy tissues, in both in vitro and in vivo studies. Concurrently, AgNP-mediated PDT has emerged as a promising approach for the eradication of bacteria and fungi, particularly those commonly associated with antibiotic resistance. The compiled data indicate that AgNPs represent an innovative and effective therapeutic alternative, with a strong potential for clinical translation, in both cancer treatment and the management of hard-to-treat infections. Full article

Electroless silver (Ag) plating has emerged as a simple yet effective surface modification technique, garnering significant attention in consumer electronics and composite materials. This study systematically investigates the influence of glucose dosage on the microstructural refinement of Ag coatings deposited from silver–ammonia solutions onto iron (Fe) particles while also evaluating the oxidation resistance of Ag-plated particles through thermogravimetric analysis. Optimal results were achieved at a silver nitrate concentration of 0.02 mol/L and a glucose concentration of 0.05 mol/L, producing Fe particles with a uniform and dense silver coating featuring an average Ag grain size of 76 nm. The moderate excess glucose played a dual role: facilitating Ag⁺ ion reduction while simultaneously inhibiting the growth of Ag atomic clusters, thereby ensuring microstructural refinement of the silver layer. Notably, the Ag-plated particles demonstrated superior oxidation resistance compared to their uncoated counterparts. These findings highlight the significance of fine-grained electroless Ag plating in developing high-temperature conductive metal particles and optimizing interfacial structures in composite materials. Full article

Alkali-soluble polysaccharides from Poria cocos (APCP) are typically discarded due to poor water solubility and limited bioavailability, despite their β-(1→3)-glucan backbone suggesting potential for functional applications. This study aimed to explore the structural characteristics, gelation behavior, and the capacity of APCP to reduce silver ions. Structural analysis confirmed that APCP is a homogenous β-(1→3)-D-glucan with a molecular weight of 314.2 kDa and a PDI of 1.32. A pH-mediated strategy enabled the formation of stable single-component APCP hydrogel (APCPH) with tunable mechanical strength, high swelling capacity (>590%), and thermal stability. The APCPH further acted as both a reducing and stabilizing matrix for in situ AgNP formation. Notably, the Ag-APCP hydrogel exhibited distinct antibacterial activity, with inhibition zones reaching 5.31 mm against Staphylococcus pseudintermedius. These findings demonstrate the feasibility of transforming underutilized APCP into multifunctional hydrogel platforms for green nanomaterial synthesis and biomedical applications. Future studies will focus on optimizing AgNP synthesis parameters and evaluating long-term stability and biocompatibility for translational use in antimicrobial therapies. Full article

Background/Objectives: This study reports the green synthesis, optimization, characterization, and multifunctional evaluation of silver nanoparticles (AgNPs) using an ethanolic Aronia melanocarpa berry extract. The objective was to establish optimal synthesis conditions; assess the in vitro stability; and evaluate the antioxidant, photocatalytic, and photoprotective activities. Methods: The cytogenotoxic effects of the AgNPs were evaluated on Triticum aestivum roots. The AgNPs were synthesized via bioreduction using an ethanolic extract of A. melanocarpa under varied pH, AgNO₃ concentration, extract/AgNO₃ ratio, temperature, and stirring time, with optimization guided by UV–Vis spectral analysis. The AgNPs were further characterized by FTIR, DLS, TEM, and EDX. In vitro stability was evaluated over six months in different dispersion media (ultrapure water; 5% NaCl; and PBS at pH 6, 7, and 8). Biological assessments included antioxidant assays (lipoxygenase inhibition, DPPH radical scavenging, metal chelation, and hydroxyl radical scavenging), photocatalytic dye degradation, and SPF determination. Results: Optimal synthesis was achieved at pH 8, 3 mM AgNO₃, extract/AgNO₃ ratio of 1:9, 40 °C, and 240 min stirring. The AgNPs were spherical (TEM), well dispersed (PDI = 0.32), and highly stable (zeta potential = −40.71 mV). PBS pH 6 and 7 ensured the best long-term colloidal stability. The AgNPs displayed strong dose-dependent antioxidant activity, with superior lipoxygenase inhibition (EC₅₀ = 18.29 µg/mL) and the effective photocatalytic degradation of dyes under sunlight. Photoprotective properties were confirmed through UV absorption analysis. The AgNPs showed a strong antimitotic effect on wheat root cells. Conclusions: The study demonstrates that A. melanocarpa-mediated AgNPs are stable, biologically active, and suitable for potential biomedical, cosmetic, and environmental applications, reinforcing the relevance of plant-based nanotechnology. Full article

Implant-associated infections, particularly those linked to Staphylococcus aureus (S. aureus), continue to compromise the clinical success of β-tricalcium phosphate (β-TCP) implants despite their excellent biocompatibility and osteoconductivity. This investigation aims to tackle these challenges by integrating femtosecond (fs)-laser surface processing with two complementary strategies: ion doping and functionalization with green-synthesized silver nanoparticles (AgNPs). AgNPs were produced via fs-laser photoreduction using green tea leaf extract (GTLE), noted for its anti-inflammatory and antioxidant properties. Fs-laser processing was applied to modify β-TCP scaffolds by systematically varying scanning velocities, fluences, and patterns. Lower scanning velocities generated organized nanostructures with enhanced roughness and wettability, as confirmed by scanning electron microscopy (SEM), optical profilometry, and contact angle measurements, whereas higher laser energies induced significant phase transitions between hydroxyapatite (HA) and α-tricalcium phosphate (α-TCP), as revealed by X-ray diffraction (XRD). AgNP-functionalized scaffolds demonstrated markedly superior antibacterial activity against S. aureus compared to the ion-doped variants, attributed to the synergistic interplay of nanostructure-mediated surface disruption and AgNP-induced bactericidal mechanisms. Although ion-doped scaffolds exhibited limited direct antibacterial effects, they showed concentration-dependent activity in indirect assays, likely due to controlled ion release. Both strategies promoted osteogenic differentiation of human bone marrow mesenchymal stem cells (hBM-MSCs) under defined conditions, albeit with transient cytotoxicity at higher fluences and excessive ion doping. Overall, this approach holds promise for markedly improving antibacterial efficacy and osteogenic compatibility, potentially transforming bone regeneration therapies. Full article

This study investigates the catalytic potential of silver nanoparticles (AgNPs) synthesized using aqueous Cymbopogon citratus (lemongrass) extract for the degradation of toxic textile dyes, offering an eco-friendly solution to industrial wastewater treatment. The green-synthesized AgNPs demonstrated remarkable degradation efficiency (>94%) for multiple dyes, such as rhodamine B, methyl red, methyl orange, methylene blue, eosin yellow, and Eriochrome black T, in the presence of sodium borohydride. Optimization studies employing a one-factor-at-a-time approach revealed the critical influence of AgNPs and reductant concentration, temperature, and pH. Kinetic analysis confirmed pseudo-first-order degradation behavior. Reactive species scavenging experiments established that hydroxyl radicals and holes played dominant roles in the degradation mechanism. Notably, the AgNPs retained catalytic activity across eight reuse cycles with negligible performance loss, demonstrating strong potential for repeated application. Comparative analysis with data from the literature highlights the superior performance of C. citratus-derived AgNPs in terms of reaction rate and efficiency. This work underscores the value of plant-extract-mediated AgNPs synthesis not only for its environmental compatibility but also for its catalytic effectiveness. The study advances the practical applicability of green nanotechnology in wastewater remediation and supports its integration into sustainable industrial practices. Full article

Nanotopography refers to the intricate surface characteristics of materials at the sub-micron (<1000 nm) and nanometer (<100 nm) scales. These topographical surface features significantly influence the physical, chemical, and biological properties of biomaterials, affecting their interactions with cells and surrounding tissues. The development of nanostructured surfaces of polymeric nanocomposites has garnered increasing attention in the fields of tissue engineering and regenerative medicine due to their ability to modulate cellular responses and enhance tissue regeneration. Various top-down and bottom-up techniques, including nanolithography, etching, deposition, laser ablation, template-assisted synthesis, and nanografting techniques, are employed to create structured surfaces on biomaterials. Additionally, nanotopographies can be fabricated using polymeric nanocomposites, with or without the integration of organic and inorganic nanomaterials, through advanced methods such as using electrospinning, layer-by-layer (LbL) assembly, sol–gel processing, in situ polymerization, 3D printing, template-assisted methods, and spin coating. The surface topography of polymeric nanocomposite scaffolds can be tailored through the incorporation of organic nanomaterials (e.g., chitosan, dextran, alginate, collagen, polydopamine, cellulose, polypyrrole) and inorganic nanomaterials (e.g., silver, gold, titania, silica, zirconia, iron oxide). The choice of fabrication technique depends on the desired surface features, material properties, and specific biomedical applications. Nanotopographical modifications on biomaterials’ surface play a crucial role in regulating cell behavior, including adhesion, proliferation, differentiation, and migration, which are critical for tissue engineering and repair. For effective tissue regeneration, it is imperative that scaffolds closely mimic the native extracellular matrix (ECM), providing a mechanical framework and topographical cues that replicate matrix elasticity and nanoscale surface features. This ECM biomimicry is vital for responding to biochemical signaling cues, orchestrating cellular functions, metabolic processes, and subsequent tissue organization. The integration of nanotopography within scaffold matrices has emerged as a pivotal regulator in the development of next-generation biomaterials designed to regulate cellular responses for enhanced tissue repair and organization. Additionally, these scaffolds with specific surface topographies, such as grooves (linear channels that guide cell alignment), pillars (protrusions), holes/pits/dots (depressions), fibrous structures (mimicking ECM fibers), and tubular arrays (array of tubular structures), are crucial for regulating cell behavior and promoting tissue repair. This review presents recent advances in the fabrication methodologies used to engineer nanotopographical microenvironments in polymeric nanocomposite tissue scaffolds through the incorporation of nanomaterials and biomolecular functionalization. Furthermore, it discusses how these modifications influence cellular interactions and tissue regeneration. Finally, the review highlights the challenges and future perspectives in nanomaterial-mediated fabrication of nanotopographical polymeric scaffolds for tissue engineering and regenerative medicine. Full article

Methylene blue (MB), a widely used industrial dye, is a persistent pollutant with documented toxicity to aquatic organisms and potential health risks to humans, even at ultra-trace levels. Conventional monitoring techniques such as UV–Vis spectroscopy and fluorescence emission suffer from limited sensitivity, typically failing to detect MB below ~10⁻⁷ M. In this study, we introduce a surface-enhanced Raman spectroscopy (SERS) platform based on silver nanowire (AgNW) substrates that enables MB detection over an unprecedented dynamic range—from 1.5 × 10⁻⁴ M down to 1.5 × 10⁻¹⁶ M. Raman mapping confirmed the presence of individual signal hot spots at the lowest concentration, consistent with the theoretical number of analyte molecules in the probed area, thereby demonstrating near-single-molecule detection capability. The calculated enhancement factors reached up to 1.90 × 10¹², among the highest reported for SERS-based detection platforms. A semi-quantitative calibration curve was established spanning twelve orders of magnitude, and this platform was successfully applied to monitor MB degradation during two advanced oxidation processes (AOPs): TiO₂ nanotube-mediated photocatalysis under UV irradiation and atmospheric-pressure dielectric barrier discharge (DBD) plasma treatment. While UV–Vis and fluorescence techniques rapidly lost sensitivity during the degradation process, the SERS platform continued to detect the characteristic MB Raman peak at ~1626 cm⁻¹ throughout the entire treatment duration. These persistent SERS signals revealed the presence of residual MB or partially degraded aromatic intermediates that remained undetectable by conventional optical methods. The results underscore the ability of AgNW-based SERS to provide ultra-sensitive, molecular-level insights into pollutant transformation pathways, enabling time-resolved tracking of degradation kinetics and validating treatment efficiency. This work highlights the importance of integrating SERS with AOPs as a powerful complementary strategy for advanced environmental monitoring and water purification technologies. By delivering an ultra-sensitive, low-cost sensor (<USD 0.16 per test) and promoting reagent-free treatment methods, this study directly advances SDG 6 (Clean Water and Sanitation) and SDG 12 (Responsible Consumption and Production). Full article