Search Results (284)

Although the modification of resin composites with antimicrobial agents represents a viable alternative for biofilm inhibition, these changes may compromise the optical and mechanical properties of dental restorations. This in vitro pilot study evaluated the effect of incorporating Nano-Silver Fluoride (NSF) containing 2000 ppm silver nanoparticles (AgNPs) on the microhardness and color of flowable resin composites: Vittra APS Unique Flowable (VA), Filtek Bulk Fill Flowable (FB), and Filtek Supreme Flowable (FS). The resin composites were modified by adding 1 wt%, 2 wt%, and 4 wt% NSF and compared with an unmodified group (control). NSF was characterized by UV–visible spectroscopy and transmission electron microscopy. The specimens were subjected to Vickers microhardness testing and color analysis using the CIEDE2000 (ΔE₀₀) and CIELAB (ΔE) systems. NSF incorporation had a material-dependent effect on microhardness. The VA group showed a progressive reduction in microhardness with increasing NSF additions, whereas the FS group remained unchanged up to the concentration of 2 wt%, and the FB group showed no significant reduction in microhardness at any of the tested concentrations compared with the control (p = 0.549). All resin composites exhibited clinically relevant color changes that increased with the NSF concentration, with more pronounced color changes in the VA group, whereas FB and FS did not vary significantly with the addition of different NSF concentrations. Overall, NSF mainly affected the optical properties, with esthetic limitations being the main challenge to be overcome in further studies. The FB and FS groups at 1 wt% and 2 wt% showed smaller chromatic changes than VA, without compromising microhardness, and appear promising for future investigations, including antimicrobial and cytotoxicity analyses. Full article

Acinetobacter baumannii is a microorganism of major global clinical importance, whose carbapenem-resistant phenotype is considered a priority target for the development of new antimicrobial agents. Carbapenem-resistant A. baumannii is associated with healthcare-associated infections and exhibits high mortality rates, prolonged hospital stays, and extensive use of intensive care units. As a control strategy, green-synthesized silver nanoparticles have gained increasing attention. Based on this, the aim of this study was to synthesize a novel triphasic silver nanocomposite, characterize it, and evaluate its antibacterial activity against extensively drug-resistant and pan-drug-resistant isolates. The nanocomposite was synthesized using cell-free bacterial supernatant and was physicochemically characterized regarding concentration, size, morphology, and crystallinity. Its antibacterial activity was assessed using broth microdilution and time–kill assays, followed by toxicity assays using human erythrocytes. A nanoscale and stable nanocomposite was obtained and was composed of metallic silver, silver chloride, and silver phosphate, which exhibited antibacterial activity against all tested isolates. In the toxicity assay, the nanocomposite demonstrated low toxicity and a high selectivity index. These findings demonstrate that Ag/AgCl/Ag₃PO₄ nanocomposite exhibits strong activity against resistant phenotypes for which therapeutic options are limited, highlighting its potential as a control strategy against this pathogen. Full article

The antibiotic and drug resistance of various bacterial and fungal strains poses a significant challenge to medicine and industry. The subject of numerous studies is how to limit the spread of microorganisms and biofilm formation on various surfaces. This research focuses on the antibacterial and antifungal properties of cross-linked methacrylate-based composites for specific applications. These composites were modified using 10 wt.% of compounds with scientifically proven antimicrobial properties. These include nanosilver, copper sulphate, benzethonium chloride, and zinc oxide. The antimicrobial potential against the following bacteria and fungi was determined: Gram-positive bacteria (Staphylococcus aureus); Gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli); and the pathogenic fungi Candida albicans and Aspergillus niger. Using the modified disc-diffusion method alongside a serial dilution method demonstrated an inhibitory effect on the viability and formation of bacterial and fungal biofilms. It was demonstrated that—in liquid cultures—composites containing benzethonium chloride inhibited the growth of P. aeruginosa by over 75%, more than 50% of E. coli and more than 70% of S. aureus. Growth inhibition of C. albicans exceeded 80% for selected composites (BPA.DM + NVP + CuSO₄, BPA.DM + NVP + ZnO), while all composites inhibited the growth of A. niger by more than 45%, and in some cases (BPA.DM + HEMA + CuSO₄, BPA.DM + HEMA + Ag, BPA.DM + MMA + Ag and BPA.DM + AEH + CuSO₄) by more than 90%. Additionally, these composites significantly reduced biofilm formation on their surfaces. Modification with zinc oxide and benzethonium chloride resulted in materials that were non-toxic to normal human skin fibroblasts. To sum up the obtained results, it can be stated that these multifunctional materials with antibacterial properties could be used in medical devices, coatings, and other specialised applications where microbial contamination is a significant issue. Full article

Introduction: Silver diamine fluoride (SDF) is a colorless solution used at different concentrations. It is a topical treatment used on caries lesions having as its main properties being cariostatic, remineralizing and antibacterial. Nanosilver fluoride (NSF) is effective as a cariostatic without a staining effect on the tooth surface as in the case of SDF, which generates a black stain on the treated surface. This NSF has been shown to exhibit low toxicity and continue to exhibit antimicrobial properties. Purpose: To compare the antibacterial effect of silver diamine fluoride and nanosilver fluoride against Streptococcus mutans. Methods: The NSF was prepared by starting with the synthesis of silver nanoparticles with chitosan and then adding it to a sodium fluoride (NaF) solution. The compared groups were SDF, NSF, AgNPs, NaF, and chlorhexidine. The antibacterial effect will be measured using the Kirby–Bauer microbiological technique. Results: The analysis of results was obtained using the ANOVA statistical test. A significant difference was obtained in the comparison between the groups with a value of p = 0.001. Subsequently, Tukey’s test was applied, obtaining significant differences between all the groups compared against the SDF, obtaining greater results in this group. Conclusions: Both silver diamine fluoride and nanosilver fluoride exhibit strong antibacterial activity at commercially recommended concentrations, supporting their use as optimal dental materials in both interceptive and preventive caries treatments. Full article

This study characterizes novel cross-linked polymeric composites based on bisphenol A glycerolate dimethacrylate (BPA.DM) as the primary matrix, incorporating 1-vinyl-2-pyrrolidone (NVP) or 2-hydroxyethyl methacrylate (HEMA) as active diluents, and modified with antimicrobial agents: zinc oxide (ZnO), copper(II) sulfate (CuSO₄), nanosilver (Ag), and benzethonium chloride (BEN). Release kinetics of active components into water and LH medium were measured over 20 days using HPLC (bisphenol A, benzethonium chloride), GF AAS (Cu, Zn, Ag), and GC–MS, revealing highest silver release from HEMA+Ag composites (1671 µg/L), substantial copper release from HEMA (354 mg/L) and NVP (319 mg/L) systems, while benzethonium chloride exhibited significantly lower migration. The effect of NVP- and HEMA-containing composites on the metabolism of the Cerrena unicolor was also assessed. Scanning electron microscopy (SEM) and optical profilometry confirmed extensive surface degradation by C. unicolor mycelium, manifesting as cracks, increased porosity, and altered surface across HEMA- and NVP-based composites after 21-day incubation. Biochemical analysis of the fungus post-culture liquids demonstrated that both composite types markedly enhanced extracellular laccase activity at all tested time points (7, 14, 21 days), with ethanol-sterilized samples inducing a slower-migrating laccase isoform identified via zymography. These materials also increased total protein concentration and superoxide anion radical levels while reducing phenolic compounds relative to controls. The findings demonstrate that antimicrobial-modified BPA.DM composites not only undergo controlled biodegradation by C. unicolor but crucially serve as potential laccase inducers, highlighting their dual utility in bioactive material design and fungal enzyme biotechnology. Full article

Dajue Temple, a representative ancient architectural heritage in North China, houses numerous lacquered wooden components of exceptional historical and artistic value. Prolonged environmental exposure causes severe dark discoloration and black spotting on lacquer surfaces, threatening their structural integrity. This first investigation into the damage identifies the spots as microbial in origin, with Cladosporium spp. as the primary agent driving deterioration and possessing wood-degrading capabilities. Antifungal tests show that thymol, clove essential oil, and nano-silver gel are all effective inhibitors. We proposed targeted, relic-friendly microbial control strategies tailored for ancient lacquered wooden components. These findings provided scientific guidance for the sustainable conservation and restoration of lacquered architectural elements in historic temples and comparable cultural heritage sites. In future work, environmental monitoring and the biocides’ compatibility should be involved, which will help to clarify microbe–environment interactions, enable early warning of biodeterioration risks and explore the wood-friendly biocides. Full article

Silver diamine fluoride (SDF) is widely used in pediatric dentistry for caries arrest; however, concerns exist regarding its cytotoxicity. Green-synthesized nano-silver fluoride (NSF) is a potential alternative to SDF, offering antimicrobial efficacy with improved biocompatibility. This study aimed to evaluate the in vitro safety profile of green-synthesized NSF with 5% (w/v) fluoride using Camellia sinensis extract and to compare it with 38% SDF + potassium iodide (KI) formulation in human gingival fibroblasts (HGFs). Eluates of NSF and SDF+KI were tested at serial concentrations of 5%, 1%, 0.1%, 0.01% and 0.005%. Cell viability was assessed after 24, 48, and 72 h using the MTT assay. Additionally, the formation of reactive oxygen species (ROS) in HGFs was detected through fluorescence microscopy. Exposure to 5% SDF+KI resulted in almost complete loss of cell viability at all time points, whereas NSF demonstrated significantly higher viability under the same conditions. Lower concentrations of both materials maintained acceptable biocompatibility. ROS analysis revealed increased oxidative stress in response to 5% SDF+KI, while NSF induced significantly lower ROS levels. NSF exhibited superior biocompatibility compared to SDF+KI, supporting its potential as a safer silver-based material for caries management. Further in vitro and in vivo studies are needed to confirm its clinical safety profile. Full article

Antimicrobial resistance is a major global health threat, creating an urgent need for effective non-antibiotic antimicrobial strategies. In this study, CS–AgNPs were synthesized by electron-beam radiolysis, providing a clean, dose-controllable route that avoids additional chemical reducing agents. The effects of irradiation dose and chitosan concentration on nanoparticle formation, physicochemical properties, and antibacterial activity were systematically evaluated. Spectroscopic and structural analyses confirmed the formation of highly crystalline, face-centered cubic silver nanoparticles uniformly dispersed within the chitosan matrix, with Ag–polymer coordination involving –NH₂ and –OH functional groups. Under the optimal conditions (8 kGy, 0.06 mmol AgNO₃, and 0.05% w/v chitosan), ultrasmall, well-dispersed CS–AgNPs were obtained, with an average size of 5.30 ± 2.01 nm and high phase purity. Antibacterial evaluation demonstrated potent, concentration-dependent activity against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, with low minimum inhibitory and minimum bactericidal concentrations (MIC/MBC = 1.96 µg/mL). These findings define a clear structure–property–activity relationship and support a synergistic antibacterial effect between nanosilver and chitosan, while maintaining favorable in vitro cytocompatibility and hemocompatibility within the effective concentration range. Overall, electron-beam radiolysis represents a promising scalable platform for producing broad-spectrum antimicrobial nanomaterials with potential utility in addressing antimicrobial resistance. Full article

Background: Nanomaterials have emerged as a transformative approach in modern pharmaceutical applications, offering advanced benefits compared to conventional therapies. Among available pharmaceutical nanomaterials, silver nanoparticles (AgNPs) have been reported with broad-spectrum antimicrobial potential and drug delivery potency. Nevertheless, some studies suggested that chemical synthesis of AgNPs might result in redundant chemicals, posing environmental and health risks. To minimize undesired products, a promising approach is to biologically synthesize this potent nanomaterial. Methods: This study ultilized an eco-friendly system for AgNPs synthesis using Aspergillus terreus isolated from the air. Physical properties of biosynthesized AgNPs were evaluated by UV–visible spectroscopy, dynamic light scattering, and scanning electron microscopy analysis. Antibacterial activity of biosynthesized AgNPs was examined by well diffusion and minimum inhibitory concentration, while in vitro cytotoxicity was used to determine the antitumor activity of AgNPs. Results: The biosynthesized AgNPs had a size of around 60 nm, a PDI inferior to 0.2, and a zeta potential of −30 mV. They exhibited potent antibacterial activity against both Gram-positive and Gram-negative pathogens. Additionally, these nanoparticles also exerted a selective antiproliferative effect on MCF-7, A549, and MDA-MB-231 cell lines. Conclusions: Our research presented the potential of biosynthesized AgNPs using Aspergillus terreus for antimicrobial and anticancer applications, offering an eco-friendly and sustainable alternative to traditional chemical methods. Full article

Background/Objectives: Wound infections caused by multidrug-resistant Gram-negative bacteria, such as Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii, pose a major clinical challenge. This study evaluated the interactions between gamma-polyglutamic acid (γ-PGA), cefiderocol, and silver nanoparticles (AgNPs) within multilayer wound dressing configurations. The primary goal was to clarify the dual role of γ-PGA as a healing promoter and a potential protector of bacterial cells against antimicrobial agents. Methods: Multilayer dressing models were assembled in 96-well plates to simulate vertical stratification of antimicrobial layers4. Bacterial viability was assessed through relative OD₆₀₀ measurements following incubation with varying concentrations and spatial arrangements of cefiderocol, AgNPs, and γ-PGA. Data were analyzed using generalized linear modeling (GLM) with a gamma distribution and random forest regression to determine the relative importance of each factor in modulating bacterial survival. Results: γ-PGA concentration emerged as the dominant factor influencing bacterial viability, accounting for nearly 100% of variable importance in random forest analysis. Despite high antimicrobial pressure from cefiderocol and AgNPs, bacterial viability stabilized at approximately 40% in the presence of γ-PGA. The vertical positioning of γ-PGA significantly impacted survival; direct physical contact between the polymer and bacteria, particularly at high concentrations, enhanced bacterial persistence in P. aeruginosa and E. coli. Cefiderocol showed strain-specific potency, while AgNPs provided consistent growth inhibition. Conclusions: γ-PGA plays a paradoxical role in wound care by providing moisture retention while simultaneously acting as a cytoprotective agent that reduces antimicrobial efficacy, likely by facilitating biofilm formation. These findings underscore the necessity of optimizing the spatial layering and concentration of biopolymers in advanced dressings. Strategic design is crucial to balance regenerative benefits with maximal antimicrobial control to improve clinical outcomes in chronic wound management. Full article

Due to the heightened flood risk resulting from climate change, innovative and advanced green building materials are required to enhance the durability and biological resistance of concrete structures exposed to persistent moisture. This study investigates the use of nanosilver-enriched plasticizers as a novel modification of concrete for applications in flood-prone environments. The findings demonstrate that the incorporation of nanosilver enhances the mechanical strength of concrete by reducing surface tension and porosity, thereby enhancing durability and extending service life. Moreover, nanosilver-modified concrete exhibits significant antimicrobial activity, effectively limiting microbial-induced corrosion. Preliminary microbiological analyses showed a reduction of sulfur-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB) by 85–92%, as well as a decrease of over 80% in potentially pathogenic microbial genera. This study also highlights the importance of skilled labor and adequate training to ensure the responsible implementation of nanosilver-based technologies in sustainable construction. Overall, nanosilver-enriched plasticizers represent an innovative green building material that supports flood-resilient, durable, and sustainable concrete construction. Full article

Cut flowers of Matthiola incana ‘Mera’ are widely used in floristics but because of wilting, premature leaf yellowing, and flower/inflorescence drying their ornamental value quickly drops. The postharvest performance of this valuable cut flower in terms of symptoms of wilting, relative water content (RWC), carbohydrate content, enzyme activity, and free proline content was studied in relation to the different preservative added to the vases with flowers. The tested preservatives were based on two biocides: 200 mg/L 8-hydroxyquinoline citrate (8-HQC) and nanosilver (NS) in two concentrations, 1 and 5 mg/L, with the addition of 2% sucrose (S). Control inflorescences were kept in distilled water alone. The above preservatives did not prolong vase life, but, on the contrary, decreased it, so flowers placed in distilled water lasted the longest. The contents of both total soluble and reducing sugars increased during flower senescence, reaching the highest level in flowers held in the solution of 5 mg/L NS plus 2% S. Similarly, the content of free proline increased, especially in flowers held in the 8-HQC with 2% S (standard preservative). The contents of hydrogen peroxide (H₂O₂) varied in flowers from different solutions; however, they kept increasing during senescence in flowers from all the treatments. The highest activity of the antioxidative enzymes was found in flowers placed in water. Full article

Sintered nano-silver is widely investigated as a die-attach material for next-generation power electronic modules due to its high thermal conductivity, favorable electrical performance, and stability at elevated temperatures. However, how bonding pressure and joint thickness jointly affect densification, interfacial diffusion, and mechanical reliability has not been systematically clarified, especially under the low-pressure conditions required for large-area SiC and GaN devices. In this work, nano-silver lap-shear joints with three bond-line thicknesses (50, 70, and 100 μm) were fabricated under two applied pressures (1.0 and 1.5 MPa) using a controlled sintering fixture. Shear testing and cross-sectional SEM were employed to evaluate the relationships between microstructural evolution and joint integrity. When the bonding pressure was increased from 1.0 to 1.5 MPa, more effective particle rearrangement and reduced pore connectivity were observed, together with improved metallurgical bonding at the Ag–Au interface, leading to a strength increase from 15.3 to 28.2 MPa. Although thicker joints exhibited slightly higher bulk relative density due to greater heat retention and accelerated local sintering, this densification advantage did not lead to improved mechanical performance. Instead, the lower strength of thicker joints is attributed to a narrower Ag–Au interdiffusion region, which limited the formation of continuous load-bearing paths at the interface. Fractographic analyses confirmed that failure occurred predominantly by interfacial delamination rather than cohesive fracture, indicating that the reliability of the joints under low-pressure sintering is governed by the quality of interfacial bonding rather than by overall densification. The experimental results show that, under low-pressure sintering conditions (1.0–1.5 MPa), variations in bonding pressure and bond-line thickness lead to distinct effects on joint performance, with the extent of Ag–Au interfacial interaction playing a key role in determining the mechanical robustness of the joints. Full article

Background: Early childhood caries is defined as a carious disease affecting primary teeth in children under 6 years of age. It may lead to pain, infections, and difficulties with eating. Despite its burden, evidence on simple, non-invasive preventive approaches which can be implemented both in dental clinics and outreach services is fragmented. The aim of this review was to identify and map such methods for the secondary and tertiary prevention of ECC and to define priorities for future research. Material and Methods: The scoping review followed the PCC framework (Population–Concept–Context). Two databases were searched: PubMed and Scopus. A systematic search was conducted in PubMed and Scopus between 1 August and 30 September 2025. Eligible studies included children under 6 years of age with existing carious lesions, evaluated non-invasive methods for secondary and tertiary ECC prevention (such as sodium fluoride (NaF), silver diamine fluoride (SDF), nano-silver fluoride (NSF), and motivational techniques), requiring simple armamentarium, and reported data on the effectiveness in the context of ECC. Only publications from the past 5 years, available in English, and in open access, were considered. The results of the analysis were summarized narratively, outlining intervention types based on their characteristics, impact, and usage context. Results: Fifteen studies were included. Most were randomized controlled trials (eight studies), focusing primarily on silver diamine fluoride (SDF), often compared with other non-invasive methods, followed by systematic reviews (two studies), reviews (two studies), cross-sectional studies (two articles), and one qualitative study. Only one publication examined the use of motivational interviewing within the context of ECC. While the evidence on non-invasive approaches is growing, significant gaps remain. Small sample sizes, short follow-up periods, and heterogenous interventions and outcomes limit comparability. To strengthen the evidence base, future studies should recruit larger cohorts, adhere to standardized procedures, and use consistent reporting. Conclusions: The majority of studies focused on SDF, reflecting the increasing interest in its use. Research on motivational interviewing in ECC is particularly scarce. Further research under standardized conditions is needed to enable reliable comparisons across treatment protocols. Full article

There is limited understanding regarding the potential toxicity of nano-silver to crayfish. This study aims to evaluate the histopathological changes, oxidative stress, transcriptomics, and intestinal microbiota changes in different tissues of crayfish after exposure to nano-silver. The results showed that exposure to nano-silver caused pathological changes in the muscles, hepatopancreas, and gills of crayfish. Damage to muscular tissue progressively worsened with increasing concentrations of nano-silver, leading to a gradual widening of the gaps between muscle fibers. Nano-silver enlarged hepatopancreatic lumen and epithelial vacuolation, while the structure of the gills became disorganized, with severe damage to the gill membranes. The activities of peroxidase (CAT), superoxide dismutase (SOD), and glutathione reductase (GSH), as well as the content of malondialdehyde (MDA) in the muscles, hepatopancreas, and gills, were altered due to nano-silver exposure. Furthermore, along with the alteration of intestinal flora, there were alterations in the diversity of intestinal microbiota, an increase in the abundance of Bacteroides and Ca_Bacilloplasma, and a decrease in the abundance of Citrobacter. The abundance of harmful bacteria increased, causing intestinal inflammatory damage. Totals of 1549 and 1305 differently expressed genes (DEG) were found in the muscles and hepatopancreas, according to transcriptome analysis. Significantly affected pathways included the PPAR signaling pathway. These findings provide valuable insights into the use of nano-silver in the aquaculture of crayfish. Full article