Search Results (1,171)

Modifying MF and UF polymer membranes with hydrophilic compounds is one of the well-known antifouling strategies, which also allows one to achieve a compromise between fluid permeability and the retention of one or another species. Hydrophilizing inorganic substances are widely used for modifying due to their enhanced chemical stability and multifunctionality. In this review, the inorganic modifiers are categorized according to their effect on organic contaminants and bacteria: (i) non-destructive (natural and synthetic aluminosilicates, phosphates and oxides of multivalent elements, particularly magnetic nanoparticles), (ii) bacteria-destructing (silver nanoparticles, advanced carbon nanomaterials, MXenes), and (iii) strongly destructive, which disrupt both bacteria and organic substances (photocatalysts). The mechanism of antibacterial activity of different modifiers is considered. The main approaches to modifying are stressed: blending polymers with preliminarily formed nanoparticles followed by membrane formation, synthesis of them inside the pores of membranes or on their surface, embedding pre-formed particles into pores, or modifying the surface with them. A comparative analysis of the functional properties and performance of pure polymer membranes and materials containing inorganic modifiers has been conducted. The attention is focused on the ability of modified membranes based on various polymers to retain both macromolecular and low-molecular-weight substances together with high fluid permeability and stability against organic contaminants and biofouling. The limitations of materials containing various types of inorganic modifiers are analyzed. Among the possible directions of further investigations, the development of a universal theoretical approach to modifying is noted; moreover, the testing of the materials has to involve the treatment of real solutions. Full article

Silver nanoparticles (AgNPs) synthesized via green approaches have attracted considerable attention because of their eco-friendly production and versatile biological and photocatalytic properties. In this study, Melissa officinalis flower extract was employed as a natural reducing, capping, and stabilizing agent for the green synthesis of AgNPs. HPLC-DAD analysis revealed that the flower extract exhibited a diverse phytochemical profile, including phenolic acids and flavonoids, which may contribute to the reduction of Ag⁺ ions and the stabilization of the synthesized AgNPs. The synthesized nanoparticles were characterized using UV–Vis spectroscopy, ATR-FTIR, SEM, DLS, zeta potential analysis, and XRD. The AgNPs exhibited predominantly spherical to hemispherical morphology with an average particle size of 40 nm and a characteristic surface plasmon resonance peak at 414 nm. DLS analysis revealed a particle size of 111.2 nm and a Z-average hydrodynamic diameter of 296.0 nm, while the zeta potential of −73.2 mV suggested high colloidal stability. XRD analysis confirmed the formation of a face-centered cubic (fcc) crystalline structure. The synthesized AgNPs exhibited photocatalytic activity, achieving degradation efficiencies of 93.6 ± 0.3% for methylene blue and 44.8 ± 0.6% for Coomassie Brilliant Blue R-250 after 180 min. In addition, the nanoparticles exhibited considerable antioxidant activity in the DPPH assay and antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Candida albicans. Overall, the findings indicate that AgNPs synthesized from M. officinalis flowers via the green synthesis method exhibited photocatalytic, antioxidant, and antimicrobial activities under the experimental conditions studied. These findings suggest that the synthesized AgNPs could be considered a potential material, particularly for dye removal and antimicrobial applications. Full article

The macroalga Kappaphycus alvarezii is a renewable source of bioactive compounds with potential in nanobiotechnology, particularly the green synthesis of metallic nanoparticles, where its extracts act as reducing and stabilizing agents. The aim of this study was to investigate the green synthesis of silver nanoparticles (AgNPs) using aqueous extracts of K. alvarezii, evaluating the influence of pH, silver nitrate (AgNO₃) and extract concentration, temperature, and reaction time, through two 2³ factorial designs with central points, as well as characterizing the obtained AgNPs by ultraviolet–visible spectroscopy (UV-Vis), dynamic light scattering (DLS), zeta potential, nanoparticle tracking analysis (NTA), and transmission electron microscopy (TEM). The selected synthesis conditions were identified as pH 13, 5.0 mg mL⁻¹ extract, and 2.5 mM AgNO₃, with two effective combinations of temperature and reaction time: 50 °C for 30 min or 60 °C for 15 min. The formation of AgNPs was confirmed by a surface plasmon resonance band at ~420 nm, showing spherical morphology, a negative zeta potential, and particle sizes ranging from 93–100 nm (NTA) to 174–192 nm (DLS), the latter reflecting the presence of aggregates in suspension. Colloidal behavior indicated partial stability, with a tendency toward aggregation during prolonged storage. Overall, these findings demonstrate the potential of K. alvarezii as a sustainable source of bioactive compounds for the synthesis of AgNPs, supporting its applicability as an antioxidant nanomaterial platform. Further biological validation and comprehensive sustainability assessments are required to evaluate its potential applications in sectors such as health, cosmetics, and agriculture. This approach reinforces the principles of Green Chemistry and aligns with several Sustainable Development Goals (SDGs), including SDG 3, 9, 12, and 14, particularly regarding the sustainable sourcing of the biomass used. Full article

Pulmonary diseases, including tuberculosis (TB), chronic obstructive pulmonary disease (COPD), asthma, lung cancer, and pulmonary fibrosis, remain a leading cause of morbidity and mortality worldwide, and each presents a different combination of diagnostic and therapeutic problems. Theranostic nanoparticles, which carry diagnostic and therapeutic functions in a single construct, have been proposed as a way to address both at once. Inorganic nanoparticles are attractive for this purpose because their optical, magnetic, and structural properties are tunable and because their surfaces tolerate extensive modification. The term theranostic, however, is applied inconsistently: much of the literature described as theranostic reports particles characterized for imaging or for therapy, but not for both on the same construct. This review applies an explicit three-tier definition, distinguishing shared-mechanism platforms, integrated platforms whose diagnostic and therapeutic modes act independently, and single-function platforms with theranostic potential. We use it to assess gold nanoparticles (GNPs), silver nanoparticles (AgNPs), mesoporous silica nanoparticles (MSNs), superparamagnetic iron oxide nanoparticles (SPIONs), and quantum dots (QDs) in pulmonary disease. Attention is given to lung-specific constraints: the difference between inhaled and systemic administration, aerodynamic requirements for deposition, mucus and surfactant interactions, alveolar macrophage uptake, mucociliary clearance, and barriers that differ between fibrotic, infective, inflammatory, and malignant disease. We address limitations by material class rather than generically, because the dominant risk differs among silver ion release, gold persistence, iron-mediated redox chemistry, silica dissolution, and heavy metal leaching from QD cores. Several inorganic nanoparticle formulations have regulatory approval, but pulmonary theranostic applications remain preclinical, and we outline what would be required to change that. Full article

Technology-related trace elements (TTEs), including rare earth elements (REEs), platinum-group elements (PGEs), silver, antimony, bismuth, barium, strontium, vanadium and radionuclide-associated elements, are increasingly relevant to environmental exposure assessment. Children and adolescents are important sentinel populations, and scalp hair offers a non-invasive matrix for multielement analysis. However, a reported hair concentration may combine follicular incorporation, sweat and sebum deposition and external particles, and may also be influenced by collection, washing, cosmetic treatment and analytical contamination. Separately, left-censoring and the statistical treatment of non-detects can materially affect population summaries and comparisons. This critical narrative review integrates paediatric, occupational, environmental and multimatrix evidence through a structured evidence matrix and an element-by-element audit of biomonitoring assessment values. Hair can identify spatial contrasts and source-related patterns, but current evidence generally does not support direct inference of absorbed dose or clinical risk. In long-term occupational REE exposure, urine shows stronger exposure-response performance than blood; paired hair–urine data for thorium discriminate exposed groups without establishing quantitative equivalence; antimony findings vary by exposure setting; and barium biomonitoring equivalents are available for urine and plasma, but not hair. No health-based guidance values validated specifically for paediatric scalp hair were identified for any of the target TTEs. A seven-stage weight-of-evidence framework is proposed, positioning hair as a complementary screening and hypothesis-generating matrix within multimatrix assessment. Full article

Food packaging materials require both antibacterial activity and mechanical strength to ensure food safety. However, conventional synthesis of silver nanoparticles (AgNPs) often involves toxic reagents or leads to particle agglomeration, and composite films usually exhibit insufficient mechanical properties. In this study, carboxymethyl chitosan (CMCS) was used as both a reducing and stabilizing agent to in situ reduce Ag⁺ under atmospheric-pressure oil-bath heating, yielding CMCS-Ag composites, which were then impregnated into carboxymethyl cellulose (CMC) films to prepare CMC-CMCS-Ag ternary composite packaging films. Under optimal conditions (102 °C, 6 h, 10 mM AgNO₃, 0.05% CMCS), AgNPs were uniformly dispersed without aggregation. The tensile strength reached 125.45 MPa, and the inhibition zone diameters against E. coli and S. aureus were 14.1 mm and 14.7 mm, respectively. This work provides a facile strategy for high-performance antibacterial food packaging films. Full article

The excessive use of fungicides in agriculture has generated environmental problems, increased resistance in plant pathogenic fungi, and raised concerns for food safety and human health. This study evaluates silver-based nanoparticles (NPs) as a potential alternative for the control of plant pathogens. Ag₂S-S Janus and AgNPs were synthesized through chemical reduction using non-toxic compounds, employing glucose as a reducing agent (0.30 and 0.90%) and gelatin as a passivating agent (0.50 and 1.00%), generating four treatments. The synthesized NPs showed average sizes ranging from 5 to 11 nm, with the smallest particles obtained in treatment T3 (5.90 ± 0.30 nm) and the largest in T4 (10.34 ± 0.46 nm). The antifungal and anti-oomycete activity of the NPs was evaluated in vitro against four microorganisms: Alternaria alternata, Colletotrichum boninense, Fusarium oxysporum, and Phytophthora capsici. Results showed complete inhibition (100%) of A. alternata and 60–70% inhibition of P. capsici in all treatments, demonstrating strong antimicrobial potential. Additionally, NPs were applied to tomato seedlings (Solanum lycopersicum) inoculated with Fusarium oxysporum f. sp. lycopersici. NPs were not phytotoxic and reduced disease severity (on a 1–2 scale) while promoting lesion healing. Full article

Gold in the coarse-grained alluvial sediments of the Irgaity placer deposit (Kazakhstan) occurs predominantly as finely dispersed particles associated with mineral matrices, which limits the efficiency of conventional recovery methods. The proposed processing flowsheet demonstrated that thermal pre-treatment is an effective approach for enhancing ultrafine gold recovery, achieving an overall recovery of 86% from the treated concentrate. The Tescan TIMA “Bright Phase Search” workflow, optimized for gold detection by applying a minimum BSE brightness threshold of 75% and an Au phase filter calibrated using a gold standard, successfully identified gold-bearing grains within the analyzed mounts. Further mineralogical investigations revealed that gold particles ≤10 μm occur as native gold and Au-Ag-As-bearing phases, with silver content reaching up to 14 wt.% in some coarser grains. The significant association of silver with gold-bearing particles indicates the potential for incorporating silver recovery into the processing flowsheet, thereby improving the overall economic value of the deposit. Despite the low average gold grade (0.3–0.4 g/t), the large dimensions of the Irgaity placer deposit (approximately 12 km long, 1.5 km wide, and 60–70 m thick) suggest the presence of a substantial large-volume mineral resource. The combination of extensive mineralized sediments and high recovery achieved through thermal activation supports the potential economic viability of the deposit and warrants further evaluation of its development potential. Full article

Self-assembled artificial nanostructures, such as DNA origami, have attracted interest as templates for the placement of inorganic materials because their design enables the incorporation of binding sites for attaching nanocomponents with nanometer-scale precision. In this work, we introduce a lithographically defined window-array substrate as an addressable platform for dark-field spectroscopic studies of individual DNA-origami-templated metallic nanostructures. The pattern was designed using the Nanometer Pattern Generation System (NPGS) software and written by electron beam lithography (EBL) on a SiO_x/Si substrate. The role of the EBL pattern is to provide spatially separated measurement sites that facilitate the localization, selection, and optical interrogation of single-particle and dimer configurations. Metallic nanostructures created by the DNA origami technique, with programmable placement of spherical gold nanoparticles (Au NPs), are used here. The nanostructures are rectangular, measuring 70 nm × 90 nm, with an Au NP attached at one corner or at two opposite corners. These seed NPs are later enlarged by controlled coalescence via electroless silver deposition. Localized surface plasmon resonance (LSPR) studies by dark-field microscopy (DFM) are presented as a proof-of-concept application for evaluating the scattering response of individual silver-metalized nanoparticles and dimers. Full article

Background: Motor and intellectual disabilities (MIDs) belong to a restricted and vulnerable social group with health restrictions for maintaining and preserving adequate oral health. Silver nanoparticles (AgNPs) have appeared as an encouraging therapy due to their excellent antimicrobial effects; however, scientific information on the antimicrobial effectiveness of AgNPs against bacteria in patients with MIDs remains limited. This study aimed to evaluate the antimicrobial substantivity of AgNPs in oral bacteria from patients with and without MIDs. Methods: Fifty-four oral biofilm samples were obtained from 26 participants with MIDs and 28 participants without MIDs. The microbial inhibition activity and the antimicrobial substantivity of AgNPs were determined. The antibiofilm activity of the AgNPs was explored using scanning electron microscopy (SEM). Results: The AgNPs displayed uniform size distributions (9.8 ± 1.7 nm) and electrical charges in surface particles that limit particle clustering (−39.8 ± 3.3 mV). The AgNPs were more effective than chlorhexidine (CHX) in eliminating bacteria from oral biofilms derived from both MID and non-MID patients (p < 0.05); therefore, the antimicrobial substantivity of the AgNPs was statistically better than deionized water but lower than CHX at specific exposure times (p < 0.05). The antimicrobial effectiveness of AgNPs at even low concentrations was associated with the type of oral biofilm, the type of antimicrobial solution, and, in some cases, gender. SEM images indicate a clear alteration in oral biofilm structure when AgNPs were applied. Conclusions: AgNPs exhibited significant potential to limit oral bacterial proliferation from microbial biofilms while contributing to the maintenance of oral condition in individuals with MIDs. Full article

Antimicrobial resistance and the limitations of conventional antimicrobial therapies have intensified the search for multifunctional nanoscale agents. Plant flowers are effective and sustainable biological materials for the eco-friendly synthesis of stable nanoparticles. In this study, Ocimum basilicum flower (OBF) extracts were used for the synthesis of silver nanoparticles (OBF-AgNPs) and evaluated for antimicrobial and antibiofilm activities. Characterization by UV–Vis spectroscopy, FTIR, SEM, TEM, EDX, DLS, and zeta-potential analysis revealed an absorption maximum at 440 nm and predominantly spherical particles measuring 5–38 nm. The hydrodynamic diameter was 53.84 nm, with a PDI of 0.4123 and a zeta potential of −23.47 mV. OBF-AgNPs showed greater antimicrobial activity than the crude extract and AgNO₃, with MIC and MBC values of 97–194 and 388–776 µg/mL, respectively. Biofilm formation was inhibited against S. aureus, P. aeruginosa, and C. tropicalis in a concentration-dependent manner. Eight GC–MS-identified phytochemicals were separately examined through network pharmacology. Of 124 predicted targets, 34 overlapped with microbial-infection-related genes, and enrichment analysis highlighted inflammatory and immune-response pathways. Molecular docking against the network-derived host-target PTGS2 showed moderate predicted interactions compared with reference inhibitors, with τ-cadinol showing the lowest docking score of −7.7 kcal/mol among the tested phytochemicals. Overall, the synthesized OBF-AgNPs demonstrated antimicrobial and antibiofilm activities. The in silico analyses independently identified host-response-related computational insights from GC–MS-identified flower constituents. Full article

The emergence of antibiotic-resistant Vibrio parahaemolyticus poses a challenge to sustainable shrimp aquaculture and highlights the need for effective antibacterial alternatives. In this study, silver nanoparticles were biosynthesized using Eri silk fibroin (ESF) as both a reducing and stabilizing biopolymer. Eri silkworms can be reared on cassava leaves, an abundant agricultural by-product in Thailand, thereby supporting waste valorization and the circular bioeconomy. Optimal synthesis was achieved at an AgNO₃-to-ESF weight ratio of 1:4, 60 °C, and 4 h, yielding 82.8% ESF-AgNPs with a particle size of 10.8 ± 2.3 nm and a polydispersity index of 0.19 ± 0.01. TEM, XRD, and XPS confirmed the formation of well-dispersed metallic Ag⁰. The particles remained colloidally stable for at least four weeks. ESF-AgNPs exhibited minimum inhibitory and bactericidal concentrations of 12.5 and 25 µg/mL, respectively; inhibited biofilm formation by 52.45–99.98%; and increased intracellular reactive oxygen species generation. After 72 h, silver release reached 5.70% in deionized water and 9.30% in TSB containing 3% NaCl. Artemia franciscana survival remained 96.2% after 24 h at the MBC. These findings support ESF as a sustainable platform for producing antibacterial and antibiofilm AgNPs with a preliminary safety margin, although further in vivo efficacy and chronic-toxicity studies are required before practical application. Full article

Various techniques are used to estimate nutrient delivery in streams that combine flow and water-quality data. However, the transport of surface floating material is difficult to measure, and is therefore typically neglected when stream sampling and in the estimated nutrient delivery. Here, we describe an approach to estimate the amount of material (duckweed (Lemna genus), filamentous algae, and other macrophyte fragments) and associated nutrients (in this case, phosphorus, P) transported on the surface of Silver Creek, Wisconsin, to determine if this material is an important transport mechanism and if historical P loads were underestimated. This approach includes estimating the transport of surface material using 10 s videos collected every 15 min from a downward-looking camera installed beneath a bridge. The average velocity of the surface material was first determined using Large-Scale Particle Image Velocimetry (LSPIV), which uses short videos to analyze surface particle movement. The amount of surface material in each video was then computed using computer-vision techniques. The P load associated with the transported surface material was then estimated by combining surface velocities, coverage of floating material, and laboratory-measured P content. Surface material transported ~9–11% of the total summer P load and ~4–7% of the annual load in Silver Creek. Full article

The primary objective of this study was to compare the contribution of cellular and cell-free filtrates of Serratia marcescens ATCC 9986 to the synthesis of silver nanoparticles, followed by a determination of the inhibitory activity on growth of S. marcescens and E. coli of the obtained biogenic silver nanoparticles. The synthesized silver nanoparticles exhibited maximum absorption at 257 nm and 262 nm when analyzed by ultraviolet–visible spectroscopy (UV–Vis). Energy-dispersive X-ray spectroscopy (EDX) analysis revealed a peak at 3 keV, corresponding to silver nanocrystals. Characterization by TEM, EDX, and IR spectroscopy demonstrated the presence of organic compounds in the nanoparticles. IR analysis revealed the presence of proteins, carbohydrates, carboxylic acids, and other compounds with saturated and unsaturated C-C bonds in the nanoparticles. Silver nanoparticles synthesized using cell-free and cellular filtrates inhibited growth of antibiotic-resistant bacteria E. coli. Moreover, cell-free filtrate of S. marcescens exerted inhibitory activity against E. coli, but not against its source, S. marcescens bacteria. Full article

Background and Objectives: This narrative review aims to evaluate the correlation between dental luting cements, peri-implantitis and the molecular mechanisms governing tissue destruction, with a specific focus on the role of autophagy and nanotechnology. Methods: A comprehensive literature search was conducted across electronic databases, including PubMed, Scopus and Web of Science, to identify relevant studies on cement cytotoxicity, cellular responses and nanomaterial integration. Results: Residual cement in the peri-implant sulcus promotes biofilm accumulation and severe inflammation. At a cellular level, resin-base monomers (e.g., Bis-GMA) impair human gingival fibroblasts via oxidative stress and mitochondrial dysfunction. Autophagy serves as a vital cytoprotective mechanism against cement toxicity and titanium particle accumulation. Experimental studies suggest that incorporating nanomaterials, specifically graphene oxide and silver nanoparticles (≤1 wt.%), has shown promising results in enhancing antimicrobial efficacy without compromising biocompatibility in vitro. Conclusions: To minimize peri-implantitis, clinical protocols should prioritize the meticulous removal of excess cement and the development of nano-reinforced luting agents. Optimizing these molecular pathways offers actionable preventive strategies, guiding clinicians toward safer cementation protocols and enhanced long-term implant success. Full article