Search Results (2,571)

Nanoemulsions are promising nanotechnology-based delivery systems that may improve the stability, bioavailability, and cellular uptake of therapeutic agents. Silver nanoparticles (AgNPs) have been reported to exhibit high antibacterial and anticancer activities via several mechanisms, such as the generation of oxidative stress and disruption of cellular membrane integrity. Breast cancer (MCF−7) and ovarian cancer (SK-OV−3) represent two highly aggressive malignancies that pose major global health challenges. Brown algae oil is a natural marine-derived product with a number of bioactive compounds, including fatty acids, sterols, and antioxidants, responsible for its numerous biological activities. Oil extracted from the brown alga Turbinaria turbinata, using hexane as an organic solvent, was formulated with silver nitrate (AgNO₃) using a surfactant-stabilized spontaneous emulsification method to prepare a silver-loaded T. turbinata oil nanoemulsion (Ag-TTO-NE). The biological performance of the system was evaluated against human cancer cell lines, including MCF−7 (breast cancer) and SK-OV−3 (ovarian cancer), in addition to pathogenic bacterial strains, and for antioxidant activity. The results demonstrated that the silver-loaded oil nanoemulsion (Ag-TTO-NE) exhibited anticancer activities against MCF−7 (breast cancer) and SK-OV−3, with IC50 values of 105.86 and 72.45 µg/mL and a Selectivity Index of 2.34 and 3.41, respectively. The silver-loaded oil nanoemulsion (Ag-TTO-NE) possessed antioxidant and antimicrobial activities against Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC90274) and Salmonella typhi (ATCC 6539). These results indicate that T. turbinata-based silver nanoemulsions deserve further exploration as multifunctional marine-derived nanoformulations. In silico ADMET analysis projected moderate to high oral absorption for most of the discovered compounds and suggested favorable pharmacokinetic properties of the individual ingredients. ADMET analysis suggested that the major compounds discovered by GC–MS have good medication-like characteristics. These computational predictions are supplemental information and are not to be taken as the pharmacokinetic behavior of the nanoemulsion itself. Overall, the present results are based on in vitro biological assays together with exploratory computational studies and constitute preliminary evidence for the subsequent exploration of this marine-derived nanoformulation. Full article

This study investigated the antiviral potential of silver nanoparticles (AgNPs) synthesized from Senna italica and Vepris reflexa plant extracts, rich in saponins and flavonoids. The aim was to explore the synthesis of AgNPs through green chemistry, followed by assessing their inhibitory activity against SARS-CoV-2 papain-like protease (PLpro) and evaluating cytotoxicity. The synthesized AgNPs were predominantly spherical in shape, with an average particle size in the nanoscale range (12–55 nm), as conformed by the transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. A dose-dependent inhibition of SARS-CoV-2 PLpro was observed, with IC₅₀ values ranging from 0.12 to 0.48 mg/mL for different formulations. Cytotoxicity tests on Vero-76 cells revealed a high viability (>75%) at concentrations below 0.5 mg/mL for all AgNP samples. The findings suggest that the plant-derived AgNPs exhibit significant antiviral activity and minimal cytotoxicity, supporting their potential for further development as therapeutic agents. Full article

In this work, we developed a novel, ultrasensitive fluorescence sensing platform for determination of organophosphorus pesticides (OPs), using chlorpyrifos as a representative model analyte. The sensing strategy was constructed upon the key inner filter effect (IFE) between graphitic carbon nitride (g-C₃N₄) nanosheets and silver-coated gold core–shell nanoparticles (Au@Ag NPs). Initially, gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), and Au@Ag NPs were successfully synthesized, and their fluorescence quenching efficiencies toward g-C₃N₄ were systematically evaluated. Owing to the superior spectral overlap with the fluorescence emission of g-C₃N₄, Au@Ag NPs exhibited the most obvious quenching effect and were thereby selected as the optimal quencher for sensor fabrication. Then, acetylcholinesterase (AChE) catalyzed the hydrolysis of acetylthiocholine (ATCH) into thiocholine. The generated thiocholine then induced aggregation of Au@Ag NPs via electrostatic and Ag-S interactions, which reduced the IFE efficiency and ultimately restored the fluorescence of g-C₃N₄. In contrast, the presence of chlorpyrifos effectively inhibits AChE activity, thereby suppressing ATCH hydrolysis and the subsequent aggregation of Au@Ag NPs. The fluorescence intensity of g-C₃N₄ was quenched by Au@Ag NPs and the signal was low. Under optimal experimental conditions, the response signal was found to be proportional to chlorpyrifos (CPF). This work presents a rapid, cost-effective, and highly sensitive approach for CPF residue analysis, holding great potential for applications in food safety monitoring and environmental surveillance. Full article

A capillary-driven microfluidic electrical screening platform was developed using silver nanoparticle (AgNP)-decorated laser-patterned villous microstructures on a glass substrate for the analysis of H3N2-infected A549 cells. The device integrated nanosecond laser patterning, AgNP conductive thin-film formation, passive capillary transport, and direct electrical readout within a single microfluidic sensing structure. Villous-like arrays were fabricated using a 1064 nm IR pulsed laser at a fluence of 4.35 J/cm², with a repetition rate of 300 kHz, pulse overlap of 96.7% and scanning speed of 500 mm/s. The fabricated structures exhibited a diameter of 60 μm, height of 80 μm and interpillar pitches ranging from 30 to 90 μm. After AgNP deposition, the surface showed a dominant Ag content of 59.2%, confirming successful formation of conductive microstructured electrodes. The 30 μm pitch structure produced the highest current response of 22 μA at 1 V and the highest ΔI_norm of 0.053 after introduction of H3N2-infected A549 samples. Wettability and capillary transport were tunable by pitch, with contact angles (CAs) decreasing from 140° to 30° and flow velocities decreasing from 0.1 mm/s to 0.03 mm/s. Formalin-fixed H3N2-infected A549 cells were electrically distinguished from non-infected A549 controls over 10¹–10⁶ PFU/μL, with detectable responses down to 10¹ PFU/μL. These results demonstrate a label-free, self-driven, and fabrication-oriented microfluidic strategy for electrical screening of virus-associated cellular samples. Full article

In this study, green-synthesized silver nanoparticles derived from Zingiber officinale (G-AgNPs) were investigated as potential modulators of transmembrane serine protease 2 (TMPRSS2), a host-associated protease involved in viral entry mechanisms. Before nanoparticle synthesis, the phytochemical composition of ginger extract was analyzed using high-performance liquid chromatography (HPLC) with photodiode array detection. Silver nanoparticles were synthesized using aqueous ginger extract as a reducing and stabilizing agent. The nanoparticles were characterized by ultraviolet–visible spectroscopy (UV–Vis.), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), zeta potential analysis, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The synthesized silver nanoparticles exhibited a face-centered cubic (fcc) crystalline structure, nanoscale particle size distribution, and moderate colloidal stability. Transmission electron microscopy revealed predominantly quasi-spherical nanoparticles with an average diameter of 10.61 ± 1.31 nm, while X-ray diffraction indicated an average crystallite size of 15.28 ± 5.48 nm. Biological evaluation demonstrated robust, broad-spectrum antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, with distinct susceptibility profiles. Minimum Inhibitory Concentration (MIC) values were 3.125 µg/mL and 12.5 µg/mL, and Minimum Bactericidal Concentration (MBC) values were 6.25 µg/mL and 25.0 µg/mL, respectively. Cell culture assays confirmed high cytocompatibility with L929 fibroblasts at all tested concentrations. In a fluorometric enzyme assay, the silver nanoparticles inhibited TMPRSS2 activity in a concentration-dependent manner, achieving 51.24% inhibition at 100 µg/mL and an estimated IC50 of 40.06 µg/mL. Although the inhibitory activity was lower than that of Camostat, the findings suggest that ginger-mediated silver nanoparticles represent promising plant-based nano-bioactive systems for further investigation of TMPRSS2 modulation. Full article

The present study introduces a novel two-step multi-analytical approach for studying lustre ceramics, aiming to minimize damage to valuable artifacts. The method combines a completely non-destructive preliminary micro-X-ray fluorescence (micro-XRF) analysis, providing semi-quantitative information and elemental mapping, with micro-destructive transmission electron microscopy (TEM) for detailed nanoparticle (NP) morphology studies on selected areas. Diffuse reflectance spectroscopy (DRS) is also employed as a non-destructive method to quantify lustre colour. This approach was applied to 20 samples of 9th- to 12th-century AD lustre ceramics from the Deraheib site in Northern Sudan. The research aimed to verify the lustre technique, characterize lustre properties (nanoparticle size, colour), and identify the ceramic production center based on glaze composition. The results from micro-XRF and TEM confirmed the presence of silver (Ag) and copper (Cu) in the lustre, with Ag NPs having a median size of 8 nm. Semi-quantitative micro-XRF analysis of the glaze indicated a composition rich in lead and tin oxides (PbO and SnO₂, 5%–15%) and magnesium oxide (MgO, 3%). This composition strongly correlates with published data for lustre ceramic production in Basra, Iraq, suggesting it as the likely origin, and ruling out Fustat, Egypt. Full article

Silver nanoparticles (AgNPs) synthesized via fungal-mediated biosynthesis have gained attention as eco-friendly alternatives to chemically produced nanomaterials, with broad biomedical potential. Fungi represent particularly attractive systems because their secretomes contain diverse biomolecules, including enzymes, proteins, polysaccharides, and secondary metabolites, capable of reducing silver ions and stabilizing the resulting nanoparticles. Despite extensive investigation, the molecular mechanisms underlying fungal-mediated AgNP formation remain poorly defined. This review critically examines the key biomolecular drivers involved in this process, with emphasis on nitrate reductases, oxidoreductases, extracellular proteins, polysaccharides, and secondary metabolites as potential reducing and capping agents. Proposed mechanisms, including nitrate reductase-dependent, superoxide-mediated, and metabolite-driven pathways, are evaluated. The influence of process parameters such as silver nitrate concentration, incubation time, culture medium composition, pH, temperature, and fungal species on nanoparticle yield, size, and stability is also assessed. Analysis of the current literature highlights significant knowledge gaps, including limited application of proteomic and metabolomic approaches, a lack of causal mechanistic studies, and insufficient standardization of experimental protocols. Overall, evidence indicates that fungal AgNP biosynthesis is governed by complex interactions among multiple biomolecular classes rather than a single universal mechanism, underscoring priorities for improving reproducibility, scalability, and mechanistic understanding. Full article

Antibiotic resistance has emerged as a major global health challenge, underscoring the urgent need for alternative therapeutic strategies capable of enhancing the efficacy of existing antibiotics. In this context, saponin-based nanomaterials have attracted considerable attention due to their potential as antibiotic-modulating systems. This study investigated a saponin-enriched fraction obtained from the bark of Sarcomphalus joazeiro Mart. (SEF-4), its application in the green synthesis of silver nanoparticles, and the antibiotic-modulating potential of the resulting nanoformulation. SEF-4 was obtained from the ethanolic bark extract through liquid–liquid partitioning (52% yield), followed by column chromatographic purification and chemical characterization using LC-ESI-QTOF-MS. The purified fraction was subsequently employed as both a reducing and stabilizing agent for the synthesis of silver nanoparticles (putative AgNP-SEF-4), which were physicochemically characterized. Antibacterial activity and antibiotic-modulating effects were evaluated using the broth microdilution method against standard and multidrug-resistant bacterial strains. LC-ESI-QTOF-MS analysis enabled the putative identification of five jujubogenin-type triterpenoid saponins bearing tetra-, penta-, and hexasaccharide moieties with distinct glycosylation profiles; however, the precise sugar sequence, monosaccharide composition, and glycosidic linkage positions remain to be confirmed through complementary NMR and hydrolysis studies. Although neither SEF-4 nor putative AgNP-SEF-4 displayed clinically relevant intrinsic antibacterial activity, the nanoformulation significantly enhanced the activity of aminoglycoside antibiotics. The most pronounced modulatory effects were observed against Klebsiella pneumoniae ATCC 1705 in combination with amikacin and against both standard and multidrug-resistant Escherichia coli strains when combined with gentamicin or amikacin. These findings highlight the potential of putative AgNP-SEF-4 as an antibiotic adjuvant capable of potentiating aminoglycoside efficacy and increasing bacterial susceptibility, including in multidrug-resistant strains. Full article

This work presents a sustainable strategy for the fabrication of multifunctional silver nanoparticles (Ag-NPs) and Ag/jute nanocomposites using Erythroxylum coca tea waste extract as a bioreducing and stabilizing agent, combined with picosecond pulsed laser irradiation. UV–Vis spectroscopy and transmission electron microscopy revealed the formation of Ag-NPs with diverse morphologies and broad size distributions, which became significantly more uniform after laser post-treatment without the need for additional chemical reagents. Following laser irradiation, the initially broad Ag surface plasmon resonance (SPR) peak transformed into a symmetric Gaussian-shaped band, centered at 407 ± 3 nm for all the Ag-NPs systems. The catalytic performance of unsupported Ag-NPs and Ag-NPs supported on jute fibers was comparatively evaluated by degrading Congo red (CR) dye, revealing that the supported nanocomposites exhibited enhanced catalytic stability, higher pollutant removal efficiency, and improved catalyst recovery. Furthermore, multicomponent catalytic reduction experiments involving CR and 4-nitrophenol (4-NP) in the presence of NaBH₄ revealed simultaneous degradation and reduction pathways mediated by the Ag/jute nanocomposites, as evidenced by the emergence of new absorption bands during the reaction. In parallel, the synthesized Ag-NPs demonstrated pronounced antimicrobial activity against Escherichia coli, generating well-defined inhibition zones. Beyond conventional approaches centered on nanoparticle synthesis and morphology optimization, this study establishes a platform that combines agricultural waste valorization, laser-assisted nanoparticle engineering, and natural-fiber-supported nanocomposite fabrication, enabling efficient remediation of both single- and multicomponent pollutant systems while promoting catalyst reusability and environmental sustainability. These findings demonstrate the Ag/jute nanocomposites as sustainable and scalable catalytic materials for wastewater remediation and antimicrobial applications. Full article

The red imported fire ant (Solenopsis invicta Buren) is a destructive invasive pest, and conventional chemical control faces challenges related to environmental contamination and resistance development, highlighting the need for novel control agents and greener management strategies. In this study, pyrethrins-mediated silver nanoparticles (Pyr-AgNPs) were synthesized via a green route, characterized, and evaluated for their insecticidal activity, environmental stability, and metabolic effects on S. invicta workers. Bait bioassays showed that Pyr-AgNPs exhibited high toxicity to S. invicta, causing 100% cumulative corrected mortality at 500 mg·kg⁻¹ after 9 days of feeding, with a 5-d LC₅₀ of 116.83 mg·kg⁻¹. Exposure assays further demonstrated that Pyr-AgNPs had good environmental stability and residual efficacy, as bait containing 1000 mg·kg⁻¹ Pyr-AgNPs still caused 100% cumulative corrected mortality after 9 days following 96 h of outdoor exposure, significantly outperforming the pyrethrins treatment. LC-MS-based untargeted metabolomic analysis revealed that treatment with Pyr-AgNPs markedly altered the metabolic profile of S. invicta workers, with 607 differential metabolites identified, mainly belonging to organic acids and derivatives, lipid and lipid-like molecules, amino acids and peptides, cofactors, and redox-related metabolites. Pathway enrichment analysis indicated that these metabolic disturbances were primarily associated with energy metabolism, redox homeostasis, and membrane lipid metabolism. Overall, these findings provide preliminary mechanistic clues into the toxicity of Pyr-AgNPs and support their potential application in the sustainable management of S. invicta. Full article

Controlling the parameters of nanoparticles within a polymer matrix is a key challenge in advancing modern materials science, particularly in developing functional cellulose-based materials. This study focused on a comprehensive comparison of in situ and ex situ methods for synthesizing silver nanoparticles (AgNPs) to determine the optimal approach for achieving precise control over nanoparticle size and distribution within Lyocell-type fibers. Cellulose fibers were produced via the NMMO (N-methylmorpholine N-oxide) method, using glucose as an eco-friendly reducing agent for silver nitrate in both approaches. The in situ method involved generating AgNPs directly during spinning dope preparation, whereas the ex situ approach utilized chemical reduction under various conditions (12 h and 24 h, 70 °C) prior to incorporating the pre-synthesized nanoparticles into the fibers. UV-Vis, DLS, and TEM measurements were employed to characterize the nanoparticles, while the resulting fibers were evaluated for their degree of cellulose polymerization, as well as their mechanical and hygroscopic properties. The comparative analysis revealed that the ex situ synthesis (24 h, 70 °C) is the optimal method, enabling superior control over the nanoparticle parameters and successfully introducing a high percentage of small-diameter AgNPs (2–8 nm) into the fiber matrix without degrading the fundamental properties of the cellulose. Full article

The experiments aimed at the green synthesis of silver nanoparticles (AgNPs) with various reducers like plant extracts and glucose and the evaluation of their antimicrobial efficiency versus their nanotoxicity. Precursor silver ions were reduced with extracts of Coffea arabica leaves, Thuja orientalis cones, and Cirsium arvense roots as well as with glucose. The AgNP microstructural properties were analyzed with transmission electron microscopy and dynamic light scattering that highlighted fine granulation (23 to 28 nm) and electrical stability (Zeta potential of −15 to −25 mV) while optical and spectral investigations like dark-field microscopy, UV-Vis spectroscopy and FTIR proved specific surface properties. Since cytotoxicity is related to the fate of AgNPs in the environment after their uses, we highlighted the presence of chromosomal alterations in the meristematic tissues of maize roots, such as delayed and expelled chromosomes, chromosome bridges, multi-polar anaphases, C-metaphases and others. Silver nanoparticle use in biomedical applications and antimicrobial activity against Gram-positive and Gram-negative pathogens was evidenced by the agar diffusion test, which suggested their usefulness in the case of possible antibiotic-resistant microbial strains with available natural ingredients and at low cost. Full article

Background/Objectives: One of the ongoing clinical constraints is limiting microbial growth on prostheses, justifying the need for material surface enhancements to reduce microbial complications. This study aimed to investigate a potentially applicable and reproducible coating technique to overcome clinical microbial challenges. Methods: Silver (Ag) nanoparticles (NPs) were applied to three types of materials through spray, spin, and dip coating techniques. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray fluorescence (EDXRF), and inductively coupled plasma optical emission spectroscopy (ICP-OES) were performed. Subsequent optimization of spray numbers was determined. Antimicrobial performance of one- and three-layered coatings was evaluated through agar diffusion, direct contact, and adhesion (time-dependent) assays against Pseudomonas aeruginosa (P. aeruginosa). Results: Spray coating exhibited superior coating uniformity. In total, 15 sprays were determined as an effective number for a single-layer coating. EDS confirmed Ag NP presence; FTIR revealed no chemical alteration. Disk diffusion tests showed no inhibition zones. Adhesion and direct contact tests displayed antibacterial activity. The effect was superior in direct contact test. Short-term time-dependent adhesion test of one-layer coating of acrylic and silicone had a consistent decrease in bacterial amount, whilst zirconium had only a strong initial activity. In general, the three-layer coating did not reveal a higher antimicrobial activity, suggesting that the increase in layering can negatively impact surface effectiveness. Conclusions: Spray coating of Ag NPs represents a potentially feasible and relevant strategy for enhancing the antibacterial properties of dental and maxillofacial prosthetic materials without compromising their inherent physicochemical characteristics, pending further cytotoxicity and in vivo validation. Full article

Microbial resistance to conventional antimicrobials is a growing public health challenge, driving the search for effective and sustainable alternatives. Among emerging strategies, the combination of silver nanoparticles (AgNPs), recognized for their potent antimicrobial action, with biosurfactants, natural, biodegradable compounds capable of interacting with microbial cell membranes and promoting their stabilization stands out. In this context, the aim of this study was to produce a biosurfactant by Candida glabrata UCP 1002 from agroindustrial residues, reducing costs and environmental impacts. The compound exhibited a surface tension of 29 mN/m, a critical micellar concentration of 0.3%, and a yield of 9 g/L; furthermore, it demonstrated stability across wide ranges of temperature, pH, and salinity. The AgNPs were synthesized using the biosurfactant as a stabilizing agent and ascorbic acid as a reducing agent, resulting in stable particles. In antimicrobial assays, the formulation inhibited Gram-positive microorganisms, Gram-negative microorganisms, and fungi. The best results were obtained against Pseudomonas aeruginosa (26.63%) and Candida albicans (28.11%), followed by Staphylococcus aureus (17.58%), Enterobacter sp. (14.42%), and Escherichia coli (13.68%). Although less effective than commercial antibiotics such as streptomycin and moxifloxacin, it showed potential as a complementary alternative in combating multidrug-resistant pathogens. Cytotoxicity assays revealed low toxicity toward normal cells (28.42% inhibition in Vero CCL-81) and minimal activity against tumor cells. The results demonstrate that the BS-AgNPs association combines relevant antimicrobial activity with environmental safety and biocompatibility, establishing itself as a promising and sustainable approach for application in health, industry, and the environment, with potential for scale-up production from low-cost raw materials. Full article

PVP-stabilized silver nanoparticles (Ag NPs) were functionalized with sildenafil (Sil), leading to spherical NPs (Ag@Sil NPs) with a size of about 30 nm as observed through transmission electron microscopy and dynamic light scattering. Fourier-transformed IR spectroscopy confirmed the covering of the particles with Sil. The Ag@Sil NPs were incorporated into a 0.1 wt% ointment and tested for the treatment of acute anal fissures in a preliminary medical study involving 50 patients. Typical symptoms such as pain, bleeding, itching, and mass sensation were improved in the intervention group with no adverse effects. Molecular docking showed strong interactions with docking scores slightly above −10 kcal/mol between sildenafil and two different model complexes [Ag–Sil]⁺ for the Ag-bound sildenafil with either piperazine-N- or pyrazole-N-bound Ag⁺ ions and the muscarinic M2 and the nicotinic acetylcholine α3β4 receptor, which are both involved in anal sphincter regulation. All three showed superior binding compared with nitroglycerin and L-arginine. The residue analysis revealed a higher number of relevant interactions for the sildenafil and the two Ag⁺ complexes, compared to nitroglycerin and L-arginine, fully in line with the differences in the docking scores. Full article