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Developing efficient catalysts for hydrogen (H 2) evolution from ammonia-borane (AB, NH 3 BH 3) is crucial for fuel cell applications. Photocatalytic hydrolysis of AB by heterogeneous catalysts under light irradiation has attracted attention as an effective technique for H 2 evolution. Here, we report an impregnation-reduction method to prepare the tungsten(VI) oxide-supported nickel/silver nanoparticles (denoted as NiAg/WO 3) and their characterization by advanced tools such as ICP-OES, PXRD, SEM, TEM, and XPS. The initial turnover frequency (TOF), activation energy (E a#), activation enthalpy (ΔH#), and activation entropy (ΔS#) values of NiAg/WO 3 nanoparticles in H 2 evolution from AB under visible light irradiation are calculated as 56.6 molH 2 ⋅ molNi 0.27 Ag 0.73 −1 ⋅ min−1, 52.14 kJ ⋅ mol−1, 47.78 kJ ⋅ mol−1, and −91.62 J ⋅ mol−1 ⋅ K−1, respectively. These findings are especially significant for a feasible application of AB in H 2 fuel cells. [Display omitted] • Ni 0.27 Ag 0.73 /WO 3 catalyst was prepared according to the impregnation-reduction method. • Characterization of the Ni 0.27 Ag 0.73 /WO 3 catalyst was performed using advanced analytical methods. • The Ni 0.27 Ag 0.73 /WO 3 catalyst provided an TOF value of 56.6 min−1 in the hydrolysis of AB under visible light irradiation. [ABSTRACT FROM AUTHOR]

Background: Addressing microbial resistance urgently calls for alternative treatment options. This study investigates the impact of a bimetallic formulation containing colistin, silver, and copper oxide on a pandrug-resistant, highly virulent Pseudomonas aeruginosa (P. aeruginosa) isolate from a cancer patient at the National Cancer Institute, Cairo University, Egypt. Methods: Silver nanoparticles (Ag NPs), copper oxide nanoparticles (CuO NPs), and bimetallic silver-copper oxide nanoparticles (Ag-CuO NPs) were synthesized using gamma rays, combined with colistin (Col), and characterized by various analytical methods. The antimicrobial activity of Col-Ag NPs, Col-CuO NPs, and bimetallic Col-Ag-CuO NPs against P. aeruginosa was evaluated using the agar well diffusion method, and their minimum inhibitory concentration (MIC) was determined using broth microdilution. Virulence factors such as pyocyanin production, swarming motility, and biofilm formation were assessed before and after treatment with bimetallic Col-Ag-CuO NPs. The in vivo efficacy was evaluated using the Galleria mellonella model, and antibacterial mechanism were examined through membrane leakage assay. Results: The optimal synthesis of Ag NPs occurred at a gamma ray dose of 15.0 kGy, with the highest optical density (OD) of 2.4 at 375 nm. Similarly, CuO NPs had an optimal dose of 15.0 kGy, with an OD of 1.5 at 330 nm. Bimetallic Ag-CuO NPs were most potent at 15.0 kGy, yielding an OD of 1.9 at 425 nm. The MIC of colistin was significantly reduced when combined with nanoparticles: 8 µg/mL for colistin alone, 0.046 µg/mL for Col-Ag NPs, and 0.0117 µg/mL for Col-Ag-CuO NPs. Bimetallic Col-Ag-CuO NPs reduced the MIC four-fold compared to Col-Ag NPs. Increasing the sub-inhibitory concentration of bimetallic nanoparticles from 0.29 × 10-2 to 0.58 × 10-2 µg/mL reduced P. aeruginosa swarming by 32–64% and twitching motility by 34–97%. At these concentrations, pyocyanin production decreased by 39–58%, and biofilm formation was inhibited by 33–48%. The nanoparticles were non-toxic to Galleria mellonella, showing 100% survival by day 3, similar to the saline-treated group. Conclusions: The synthesis of bimetallic Ag-CuO NPs conjugated with colistin presents a promising alternative treatment for combating the challenging P. aeruginosa pathogen in hospital settings. Further research is needed to explore and elucidate the mechanisms underlying the inhibitory effects of colistin-bimetallic Ag-CuO NPs on microbial persistence and dissemination. [ABSTRACT FROM AUTHOR]

This report demonstrates the synthesis of a trihybrid system (PBI-NP-GO) consisting of perylene bisimide appended peptide (PBI-UW) nanofibers, silver nanoparticles (PBI-AgNP), and graphene oxide (GO) nanosheet. Tryptophan-containing PBI molecules in an aqueous medium can reduce silver ions into silver nanoparticles in the presence of sunlight to form a dihybrid system consisting of nanofibers and nanoparticles; the addition of GO into the dihybrid system ultimately leads to the formation of the trihybrid system. The trihybrid system was thoroughly characterized by various spectroscopic and microscopic techniques, such as ultraviolet-visible (UV-vis), Fourier transform-infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), RAMAN, and field emission transmission electron microscopy (FEG-TEM). The so-formed trihybrid system was successfully utilized as a potential photocatalyst for the reduction of carcinogenic Cr(VI) to non-toxic Cr(III) under irradiation with blue LED light. An almost complete reduction of Cr(VI) was achieved within 30 minutes of irradiation. Moreover, good photo-switching behaviour was observed with the highest photocurrent gain of 5.11 (Ion/Ioff) compared to PBI-AgNP (dihybrid) and PBI-UW, where Ion/Ioff values of 3.92 and 2.31, respectively, were obtained. The photocatalytic activity and photo-switching behaviour of the trihybrid system are due to efficient photo-induced charge separation. [ABSTRACT FROM AUTHOR]

The emergence of antibiotic-resistant bacteria necessitates the development of novel, sustainable, and biocompatible antibacterial agents. This study addresses cytotoxicity and environmental concerns associated with traditional silver nanoparticles (AgNPs) by exploring lignin, a readily available and renewable biopolymer, as a platform for AgNPs. We present a novel one-pot synthesis method for lignin-based AgNPs (AgNPs@AL) nanocomposites, achieving rapid synthesis within 5 min. This method utilizes various organic solvents, demonstrating remarkable adaptability to a wide range of lignin-dissolving systems. Characterization reveals uniform AgNP size distribution and morphology influenced by the chosen solvent. This adaptability suggests the potential for incorporating lignin-loaded antibacterial drugs alongside AgNPs, enabling combined therapy in a single nanocomposite. Antibacterial assays demonstrate exceptional efficacy against both Gram-negative and Gram-positive bacteria, with gamma-valerolactone (GVL)-assisted synthesized AgNPs exhibiting the most potent effect. Mechanistic studies suggest a combination of factors contributes to the antibacterial activity, including direct membrane damage caused by AgNPs and sustained silver ion release, ultimately leading to bacterial cell death. This work presents a straightforward, adaptable, and rapid approach for synthesizing biocompatible AgNPs@AL nanocomposites with outstanding antibacterial activity. These findings offer a promising and sustainable alternative to traditional antibiotics, contributing to the fight against antibiotic resistance while minimizing environmental impact. [ABSTRACT FROM AUTHOR]

Previous research using the model soil nematode Caenorhabditis elegans has revealed that silver nanoparticles (AgNP) and their transformed counterpart, sulfidized AgNP (sAgNP), reduce their reproduction and survival. To expand our understanding of the environmental consequences of released NP, we examined the synergistic/antagonistic effects of AgNP and sAgNP along with AgNO3 (ionic control) on C. elegans infected with the pathogen Klebsiella pneumoniae. Individual exposures to each stressor significantly decreased nematode reproduction compared to controls. Combined exposures to equitoxic EC30 concentrations of two stressors, Ag in nanoparticulate (AgNP or sAgNP) or ionic form and the pathogen K. pneumoniae, showed a decline in the reproduction that was not significantly different compared to individual exposures of each of the stressors. The lack of enhanced toxicity after simultaneous combined exposure is partially due to Ag decreasing K. pneumoniae pathogenicity by inhibiting biofilm production outside the nematode and significantly reducing viable pathogens inside the host. Taken together, our results indicate that by hindering the ability of K. pneumoniae to colonize the nematode's intestine, Ag reduces K. pneumoniae pathogenicity regardless of Ag form. These results differ from our previous research where simultaneous exposure to zinc oxide (ZnO) NP and K. pneumoniae led to a reproduction level that was not significantly different from the controls. [ABSTRACT FROM AUTHOR]

This paper presents the syntheses of SiO2 particles immobilized with Ag nanoparticles and their composite with Au. Ag nanoparticles are present on the surfaces of the SiO2 particles, and Ag+ ions are galvanically replaced with Au3+ ions. Finally, a method for maintaining the color durability and dispersibility of the Ag nanoparticles is demonstrated. The particles are primarily synthesized in three steps: In the first step, Sn2+ ions are adsorbed on the surfaces of the SiO2 particles; in the second step, Ag+ ions are added, which are reduced and simultaneously adsorbed on the surface while Sn2+ is oxidized to Sn4+; in the third step, Au3+ ions are reduced by galvanic replacement and deposited on the Ag surface. Extensive characterization using transmission electron microscopy, scanning transmission electron microscopy, ultraviolet-visible spectroscopy, and X-ray photoelectron spectroscopy reveals that the Ag–Au composite nanoparticles (17.2 ± 4.1 nm) are immobilized on the surface of the SiO2 particles (<1 µm). The morphology and coloration of the SiO2 particles with the immobilized Ag–Au composite nanoparticles remain preserved in nitric acid. This preservation is more pronounced than that observed in SiO2 particles with immobilized Ag nanoparticles. This enhanced durability can be attributed to the formation of stable bonds between Ag and Au. [ABSTRACT FROM AUTHOR]

The accurate and sensitive determination of tyrosine is of paramount value. In this work, we reported the synthesis and characterization of a new nanohybrid composed of silver nanoparticles and hollow carbon nanospheres (Ag/HMCS) for the amperometric sensing of tyrosine. The Ag/HMCS nanohybrid was used to modify electrodes and to fabricate an amperometric sensor for tyrosine at a working potential of 450 mV in aqueous 0.1 M phosphate buffer at pH 7.0. Under optimal conditions, the sensor determined tyrosine from 0.08 to 100 μM with a detection limit of 0.02 μM. [ABSTRACT FROM AUTHOR]

In this research, the explosive wire method is used to prepare silver nanoparticles and study their effect on two types of bacteria, E. coli and Staphylococcus aureus. The X-ray diffraction pattern of silver nanoparticles after deposition on glass pieces shows a peak of silver and silver oxide. The FE-SEM morphology of silver oxide particles shows small spherical-like clusters of irregular flower-shaped particles. Meanwhile, the AFM analysis of the silver nanoparticles shows that the average roughness of the aggregates is 57 nm and the average size of the nanoparticles is 20.92 nm. The study of the effect of silver nanoparticles on two types of bacteria, namely E. coli and Staphylococcus aureus, has shown that these nanoparticles have achieved a killing rate of 99% for both types of bacteria. [ABSTRACT FROM AUTHOR]

The use of plants in the biological production of silver nanoparticles for antibacterial applications is a growing field of research. In the current work, we formulated Ocimum kilimandscharicum extracts using silver nanoparticles, and evaluated its potential antibacterial activity. Aqueous and methanol plant extracts were used to reduce silver nitrate at different time intervals (30 to 150 minutes) and pH (2 to 11). The UV-visible absorption spectrum recorded for methanol and aqueous extracts revealed a successful synthesis of AgNPs for methanol and aqueous extracts. The antimicrobial activity of the AgNPs was evaluated against Escherichia coli ATCC 25922, Salmonella choleraesuius ATCC 10708, and Staphylococcus aureus ATCC 25923 The best inhibition zone for the methanol and aqueous-mediated AgNPs, ranging from 12 ± 1 to 16 ± 1mm. Additionally, the methanol and aqueous extract silver nanoparticles had the same Minimum Inhibitory Concentration (6.25 ± 0.00 mg/ml), whereas the Minimum Bactericidal Concentrations were 12.5 ± 0.00 and 25 ± 0.00 mg/ml, respectively. The highest inhibition zone of 16 ± 1 mm was observed against Salmonella choleraesuius with 50 ± 0.00 mg/ml aqueous silver nanoparticles. The results show that the silver nanoparticles made with Ocimum kilimandscharicum have antibacterial action against those microorganisms. [ABSTRACT FROM AUTHOR]

Aluminum can be found in water and vegetables in the form of the trivalent ion (Al3+), which can potentially contaminate food and water. Overconsumption of aluminum can lead to serious health problems in humans. Therefore, there is a need for an economical and simple procedure to detect the presence of aluminum. In this study, we synthesized a conjugate of Grewia asiatica extract with silver nanoparticles. The nanoparticle-stabilized fruit extract of Grewia asiatica was found to be an extremely selective sensor of Al3+ in tap water, DI water, industrial wastewater, and human blood plasma. We characterized the Grewia asiatica-conjugated silver nanoparticles (GA-AgNPs) using UV-visible, SEM, and AFM techniques and found that they were stable in an extensive pH range and different electrolyte concentrations up to 10 M NaCl. The GA-AgNPs were circular in shape with typical particle sizes of 65–97 nm. We inspected the photo physical properties of GA-AgNPs concerning metallic ions using UV-visible spectroscopy and found that they were highly selective for Al3+ ions, with no interfering ions detected in competitive experimentation. The absorption intensity of GA-AgNPs was directly related to Al3+ concentration over a wide range of concentrations (6.25–500 μM). Jobs plot experiment displayed 1 : 1 binding stoichiometry between GA-AgNPs, and Al3+. Additionally, GA-AgNPs were effectively utilized for the recognition of Al3+ in laboratory tap water, DI water, industrial wastewater, and human blood plasma. [ABSTRACT FROM AUTHOR]

This paper describes a simple approach for creating silver (Ag) nanocubes using pulsed laser ablation in a liquid medium. The development of nanocubical formations of Ag obtained by laser ablation using Nd: YAG laser was conducted for 5, 10, 15, and 20 min. The surface morphological analysis was performed using field-emission scanning electron microscopy (FESEM) to show the formation of silver nanocubes with edge lengths ranging from 150 nm to 250 nm. The UV-visible spectroscopy demonstrates that the concentration of Ag nanostructures, evidenced by the characteristic localized surface plasmon resonance band near 400 nm in the colloidal solution containing Ag nanoparticles, increased with the increasing laser ablation duration from 5 min to 20 min. The growth mechanism for Ag nanocubes can be easily understood with the change in laser ablation time from 5 to 10, 15, and then 20 min. The Ag sheets with no specific shape start to develop after 5 min of laser ablation, and after 10 min, larger particles form. Then, after 15 min, a small number of cube-like nanostructures with rough and uneven edges was obtained. At the end of 20 min, a complete cubic formed with fine and distinct edges and a very large amount of nanocubes. The elemental silver signal was present in Ag nanocubes, as revealed by the energy-dispersive X-ray spectroscopy (EDS) spectra. The produced Ag nanocubes may be used to construct two-dimensional nanocomposites with practical applications in the electrical, optoelectronic, electrochemical, and biological areas. [ABSTRACT FROM AUTHOR]

In this study, Fe3O4/Ag magnetite-silver (MSx) nanocomposites were investigated as catalysts for advanced oxidation processes by coupling the plasmonic effect of silver nanoparticles and the ferromagnetism of iron oxide species. A surfactant-free co-precipitation synthesis method yielded pure Fe3O4 magnetite and four types of MSx nanocomposites. Their characterisation included structural, compositional, morphological and optical analyses, revealing Fe3O4 magnetite and Ag silver phases with particle sizes ranging from 15 to 40 nm, increasing with the silver content. The heterostructures with silver reduced magnetite particle aggregation, as confirmed by dynamic light scattering. The UV–Vis spectra showed that the Fe:Ag ratio strongly influenced the absorbance, with a strong absorption band around 400 nm due to the silver phase. The oxidation kinetics of organic pollutants, monitored by in situ luminescence measurements using rhodamine B as a model system, demonstrated the higher performance of the developed catalysts with increasing Ag content. The specific surface area measurements highlighted the importance of active sites in the synergistic catalytic activity of Fe3O4/Ag nanocomposites in the photo-Fenton reaction. Finally, the straightforward fabrication of diverse Fe3O4/Ag heterostructures combining magnetism and plasmonic effects opens up promising possibilities for heterogeneous catalysis and environmental remediation. [ABSTRACT FROM AUTHOR]

An original plasma chemical process initiated by microwave discharge in a mixture of metal and dielectric powders was applied to prepare specific materials, which consisted of microsized spherical particles of aluminum oxide covered with silver nanoparticles. The prepared materials are highly uniform in shape, size distribution, and composition. Their cytotoxicity was investigated using the human cell lines MCF7, HEK293T, A549, and VA-13 and the bacterial strains E. coli JW5503 (ΔtolC) and E. coli K12. Their cytotoxicity was found not to exceed the cytotoxicity of the starting materials. Thus, the prepared materials can be considered highly promising for catalysis and biotechnology applications. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) conjugated with polymers are well-known for their powerful and effective antimicrobial properties. In particular, the incorporation of AgNPs in biocompatible catecholamine-based polymers, such as polydopamine (PDA), has recently shown promising antimicrobial activity, due to the synergistic effects of the AgNPs, silver(I) ions released and PDA. In this study, we generated AgNPs-PDA-patterned surfaces by localised electrochemical depositions, using a double potentiostatic method via scanning electrochemical cell microscopy (SECCM). This technique enabled the assessment of a wide parameter space in a high-throughput manner. The optimised electrodeposition process resulted in stable and homogeneously distributed AgNP-microspots, and their antimicrobial activity against Escherichia coli was assessed using atomic force microscopy (AFM)-based force spectroscopy, in terms of bacterial adhesion and cell elasticity. We observed that the bacterial outer membrane underwent significant structural changes, when in close proximity to the AgNPs, namely increased hydrophilicity and stiffness loss. The spatially varied antimicrobial effect found experimentally was rationalised by numerical simulations of silver(I) concentration profiles. [ABSTRACT FROM AUTHOR]

Metal nanoparticles incorporated into carbon nanostructures have tremendous applications in the field of nanosensors and other technologies. Herein, a nanohybrid of reduced graphene oxide modified with silver and/or palladium nanoparticles (Ag/Pd/rGO) was prepared by impregnation of Pd and Ag into the rGO platform and deposited on a glass carbon electrode. Palladium and silver nanoparticles improve the stability and durability of the sensor platform by preventing the agglomeration of graphene oxide sheets and providing chemical stability against environmental factors. This ensures long‐term reliability and repeatability of the sensor performance. The morphologies and microstructures of the as‐prepared nanohybrid were characterized by X‐ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, UV–visible and infrared spectroscopy. The average crystallite size of PdAgNPs was found to be between 12 and 15 nm and demonstrated good dispersion across reduced graphene oxide sheets with high‐loading capacities. Thorough investigation of the electrochemical properties of the nanomaterial surfaces through cyclic voltammetry (CV) experiments, revealed distinct redox peaks for Ag+/Ag0 and Pd2+/Pd0 processes and demonstrated the excellent electrochemical properties of the prepared nanocomposites. The rGO‐PdAgNPs‐GCE had a diffusion coefficient value of 1.14×10−14 cm2 s−1 which is acceptable for electrochemical sensors as it is indicative of a fast response time and enhanced sensitivity to changes in gas concentration. The results obtained through thorough characterizations contributes to the novelty of the research by offering a deeper understanding of the material properties and the potential of the nanohybrid material for a broad application scope. [ABSTRACT FROM AUTHOR]

The present research studied the cytotoxicity, antioxidant, and antidiabetic activities of biogenically synthesized silver nanoparticles (AgNPs) using Ziziphora clinopodioides (Z. clinopodioides) as a green mediator. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet–visible spectroscopy (UV–Vis) were employed to determine AgNPs. In the in vivo experiment, the model rats were categorized into different groups receiving 50, 100, 200, and 400 μg/kg of AgNPs and diabetic, positive, and normal groups (n = 10) using a random division. A single dose of streptozotocin (STZ) at 60 mg/kg was administered to induce diabetes and hepatotoxicity in rats. The administration of AgNPs was performed via intragastric administration for 25 days. On the final day, the levels of glucose and biochemical enzymes, namely aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine transaminase (ALT), and gamma‐glutamyltransferase (GGT), were assessed in the serum. Following tissue processing, liver sections with a thickness of 5 μm were prepared. Later, the total volume of different liver components, such as hepatocytes, sinusoids, portal vein, central vein, hepatic arteries, and bile ducts, was measured. The portal vein and bile duct volumes did not vary significantly in groups treated by AgNPs. However, the volume of the central vein and hepatic arteries exhibited noticeable variations in groups treated by AgNPs. After administration of streptozotocin, the volume of hepatocytes and sinusoids increased significantly. However, treatment with a high dose of AgNPs significantly decreased the volume of hepatocytes and sinusoids. In diabetic rats, administering AgNPs reduced the fasting blood glucose levels compared to the model group. In addition, AgNPs decreased the elevated levels of AST and ALP enzymes in a manner that depended on the dosage of AgNPs used. This research demonstrates the hepatoprotective and antidiabetic properties of AgNPs, suggesting their potential implications as hepatoprotective and antidiabetic supplements to prevent diabetes. [ABSTRACT FROM AUTHOR]

Silver/polymeric vesicle composite nanoparticles with good antibacterial properties were fabricated in this study. Silver nanoparticles (AgNPs) were prepared in situ on cross‐linked vesicle membranes through the reduction of silver nitrate (AgNO3) using polyvinylpyrrolidone (PVP) via coordination bonding between the Ag+ ions and the nitrogen atoms on the vesicles. X‐ray diffraction (XRD), ultraviolet‐visible spectroscopy (UV‐vis), and transmission electron microscopy (TEM) analyses confirmed the formation of AgNPs on the vesicles. The antibacterial test demonstrated good antibacterial activity against both Gram‐negative bacteria (Escherichia coli) and Gram‐positive bacteria (Staphylococcus aureus) for the produced AgNP‐decorated vesicles. The minimum inhibitory concentration (MIC) values of the AgNP‐decorated vesicles for E. coli and S. aureus were 8.4 and 9.6 μg/mL, respectively. Cell viability analysis on the A549 cells indicated that the toxicity was low when the AgNP concentrations did not exceed the MIC values, and the wound healing test confirmed the good antibacterial properties of the AgNP‐decorated vesicles. [ABSTRACT FROM AUTHOR]

[Display omitted] Novel two-dimensional MXene with unique optical and electrical properties has become a new focus in the field of sensing. In particular, their metallic conductivity, good biocompatibility and high anchoring ability to biomaterials make them attractive candidates. Despite such remarkable properties, there are certain limitations, such as low oxidative stability. MXene-Metal interactions are an effective strategy to maintain the long-term stability of MXene, while also improving the electrochemical activity and optical properties. Herein, a series of MXene/Ag nanocomposites including Ti 3 C 2 /Ag, Nb 2 C/Ag and V 2 C/Ag were designed based on the surface chemistry characteristics of MXene, where MXene served as the substrate for in-situ growth of silver nanoparticles via self-reduction of Ag(NH 3) 2 +. The results showed that V 2 C MXene has the strongest self-reducing ability due to its multiple variable valence states, larger interlayer space and more reactive groups. Moreover, V 2 C/Ag exhibited unexpected oxygen reduction reaction catalytic activity and photothermal performance. In view of which, an electrochemiluminescence-photothermal (ECL-photothermal) immunosensor was developed using V 2 C/Ag as ECL anchor and photothermal reagent for ultrasensitive detection of Lipolysis stimulated lipoprotein receptor. This work not only provides a simple and effective synthesis method of MXene supported metal nanocomposites, but also provides more inspirations for exploring the efficient biosensing strategies. [ABSTRACT FROM AUTHOR]

This study presents a green, novel, one-pot, and single-step method for synthesizing reduced graphene oxide/silver nanocomposites (RGO/Ags) with different Ag ratios using Roselle extract and 80kGy of γ-ray for symmetric supercapacitor applications. As a natural antioxidant, Roselle extract served as a scavenger of oxidative free radicals to inhibit the oxidation of graphene oxide/silver nitrate suspensions (GO/AgO3), which were undergoing radiolysis under γ irradiation. An additional sample of GO/AgO3 was irradiated with the same dose in the absence of Roselle for comparability. The efficient reduction of GO/AgO3 has been assessed by several analytical techniques, including XRD, FTIR, TEM, and Raman spectroscopy. The presence of Roselle hindered the formation of the AgO phase while concurrently promoting the construction of the Ag phase. Furthermore, using Roselle extract results in a more homogeneous dispersion of spherical silver nanoparticles on reduced graphene oxide (RGO) sheets. Symmetric supercapacitor has been assembled from arbitrary samples amongst RGO/Ags, which showed good performance like low internal resistance and suitable specific capacitance (96 F/g at current density 0.2 A/g). The findings point to the merit of RGO/Ag nanocomposites prepared by the synergetic effect of γ-ray and Roselle extract as an efficient supercapacitor material. [ABSTRACT FROM AUTHOR]

The development of an effective and eco-friendly silver nanoparticle (AgNPs) to abate the effect of abiotic stress is an important area of nano-biotechnology. This study aimed to study the priming effect of plant-based green-synthesized silver nanoparticles and melatonin on the physiological and biochemical activities of drought-stressed E. uniflora. Sterilized seeds of E. uniflora were primed with 0.06 mg/l of ML-AgNPs, 0.06 mg/l of melatonin, and a nano-silver formulation of melatonin (1:1). Primed seeds were planted and subjected to 7 days under drought stress. The ML-AgNPs enhanced germination percentage, speed and vigor, and shoot elongation and induced the production of APx, CAT, and proline dehydrogenase (100% increases). Melatonin improved the activities of APx and CAT, total protein, accumulation of proline, and proline dehydrogenase (200% increases) and stabilized MDA content. Meanwhile, silver nano-formulation of melatonin increased leaves proliferation of leaves and production of APx, GPx, SOD, and CAT. Accumulation of proline and 100% upregulation of proline dehydrogenase osmo-regulated the effects of the drought, reduced MDA contents, and stabilized the excessive production of H2O2 and O2−. The ML-AgNO3 showed an efficient delivery system of melatonin into the plant under drought stress. As a result, our research shows that melatonin in silver nano-formulation (1:1) is a useful biostimulant against drought stress. [ABSTRACT FROM AUTHOR]

Early detection of diseases can increase the chances of successful treatment and survival. Therefore, it is necessary to develop a method for detecting or sensing biomolecules that cause trouble in living organisms. Disease sensors should possess specific properties, such as selectivity, reproducibility, stability, sensitivity, and morphology, for their routine application in medical diagnosis and treatment. This work focuses on biosensors in the form of surface-functionalized gold (AuNPs) and silver nanoparticles (AgNPs) prepared using a less-time-consuming, inexpensive, and efficient synthesis route. This allows for the production of highly pure and stable (non-aggregating without stabilizers) nanoparticles with a well-defined spherical shape, a desired diameter, and a monodisperse distribution in an aqueous environment, as confirmed by transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM-EDS), X-ray diffraction (XRD), photoelectron spectroscopy (XPS), ultraviolet-visible (UV-VIS) spectroscopy, and dynamic light scattering (DLS). Thus, these nanoparticles can be used routinely as biomarker sensors and drug-delivery platforms for precision medicine treatment. The NPs' surface was coated with phosphonate dipeptides of L-leucine (Leu; l-Leu–C(R1)(R2)PO3H2), and their adsorption was monitored using SERS. Reproducible spectra were analyzed to determine the orientation of the dipeptides (coating layers) on the nanoparticles' surface. The appropriate R2 side chain of the dipeptide can be selected to control the arrangement of these dipeptides. This allows for the proper formation of a layer covering the nanoparticles while also simultaneously interacting with the surrounding biological environment, such as cells, tissues, and biological fluids. [ABSTRACT FROM AUTHOR]

Formation of Ag nanoparticles in the PbO–Bi 2 O 3 –Ga 2 O 3 heavy metal oxide glasses modified by addition of Ag 2 O and Sb 2 O 3 was monitored using electrical and optical measurements. Electrical measurements are suitable for this purpose as they are very sensitive to any changes in the arrangement of the material structure. The formed spherical silver nanoparticles were studied by a high-resolution transmission electron microscopy (HRTEM), their nature was confirmed by selected area electron diffraction analysis (SAED) and x-ray photoelectron spectroscopy (XPS). We demonstrated and documented that the samples containing Ag/Sb change during additional heating (in the investigated temperature range of 240–290 °C) – the electrical conductivity changes and also the relaxation time as established by electrical modulus measurements changes. The behaviour of the base glass without Ag/Sb addition remains practically unaffected by the same additional heating. TEM confirmed an increased number of spherical nanoparticles as a consequence of heat treatment. The indexes of the SAED pattern match the fcc-Ag crystalline phase, HRTEM identified the periodical arrangement in these particles to correspond to d-spacing of (111) planes in Ag and the elemental state of the present Ag in the heat-treated sample was confirmed also by XPS. [ABSTRACT FROM AUTHOR]

Background: Soybean rust caused by Phakopsora pachyrhizi Syd. is one of the major constraints in the production of soybean. Nanotechnology is a new scientific approach that includes use of materials and equipment capable of using physical and chemical properties of a substance at molecular level to explore the biological and material worlds in nanometer-scale and use it in various carriers from medicine to agriculture. Nanotechnology has emerged as one of the most innovative scientific field in agriculture. Among various synthesis methods, green synthesis of nanoparticles is widely used by researchers because it is simple, convenient, eco-friendly and requires less reaction time. Methods: The chitosan based zinc oxide nanoparticles (Ch-ZnONPs), pomegranate aril based sulphur nanoparticles (PA-SNPs) and pomegranate aril based silver nanoparticles (PA-AgNPs) were synthesised, characterised and evaluated under in vitro conditions against soybean rust pustules. Result: The maximum per cent spore inhibition of 70.25, 74.70 and 86.68 per cent over control was recorded in Ch-ZnONPs (1250 ppm), PA-SNPs (2000 ppm) and PA-AgNPs (500 ppm) respectively. [ABSTRACT FROM AUTHOR]

The study aims at synthesizing a simple, cost-effective, selective, and sensitive colorimetric sensor based on chlorophyll-coated silver nanoparticles (Chl-AgNPs) using microwave-assisted method for the determination of Cr(VI) ions in an aqueous medium. The characterization reveals that synthesized nanoparticles are 20–30 nm in size and spherical in shape. The presence of methyl, carboxyl, aldehyde, and ketone groups on the surface of Chl-AgNPs results in the formation of size controlled, well dispersed, and stable silver nanoparticles. The prepared nano-colloidal solution has been used for selective and sensitive determination of Cr(VI) in water samples. The addition of single drop of Chl-AgNPs solution immediately changes the color of water samples containing Cr(VI) to red displaying good sensitivity from 10 to 100 µM and high selectivity even in the presence of other metal ions. The ultraviolet–visible spectra show that in the presence of Cr(VI), the localized surface plasmon resonance (LSPR) band of Chl-AgNPs at 410 nm shifts to 470 nm with a new peak at 357 nm. Furthermore, the absorbance of the LSPR band decreases and the absorbance at 357 nm increases linearly with the concentration of Cr(VI). The functional groups on the surface of nanoparticles bind Cr(VI) on the surface leading to agglomeration and alterations in interparticle distance that are observed as changes in the color and LSPR profile. The limits of detection and quantification for Cr(VI) ions were determined to be 0.62 µM and 1.88 µM, respectively. [ABSTRACT FROM AUTHOR]

Topical anticaries agents are non‐invasive methods to control and prevent dental caries. SDF is a fluoride‐based agent added to the arsenal of caries prevention tools. It has got a lot of attention since its introduction in the 1970s because of its ability to prevent and arrest caries, as well as its excellent antibacterial and anti‐plaque action. SDF reduces acid production by microorganisms, decreases the Streptococcus mutans count, biofilm formation, increases enamel resistance, and promotes dentinal tubule obliteration when applied to the dental surface. SDF also assists in the remineralization of dentin. A biannual application of 38% SDF has been effective at preventing dentin demineralization. This "silver bullet" can be seen as an alternative for caries prevention in special health care needs children which is minimally invasive and safe. Along with the advantages, there are some disadvantages, and work has been carried out to explore the use of silver nanoparticles (SNP) as anticaries agents to shield the teeth from aesthetic damage caused by Silver diamine fluoride. SNPs are identified to have the potential to prevent and inhibit dental caries while not discoloring demineralized dental enamel. SNPs have a greater surface area for interaction with microorganisms than other particles, making them more effective antimicrobial agents. Fluoride combined with SNP solution has a synergistic effect that promotes enamel remineralization while also acting as a bactericidal agent against cariogenic microorganisms. This review aims to bring out the various advantages and disadvantages related to the use of SDF and SNPs to aid in future research. [ABSTRACT FROM AUTHOR]

Polymer nanocomposite materials with catalytic activity were designed via modification of MF-4SK ion-exchange membranes with Au and Ag nanoparticles obtained according to various synthetic methods in reverse micellar solutions. A sufficient transparency of the films allowed us to detect nanoparticles in the films using UV–Vis spectrophotometry, monitoring changes in the content of metal nanoparticles in the reverse micellar solution. A different mechanism of interaction of Au and Ag nanoparticles obtained by the same synthetic method with the MF-4SK film upon their contact with its surface was discovered, the destruction of nanoparticles was observed, and the influence of mechanism of primary acts in the formation of metal nanoparticles in reverse micellar solutions on their adsorption properties was confirmed. The highest concentration of gold nanoparticles was found in films immersed in reverse micellar solutions at the time of their exposure to ionizing radiation. [ABSTRACT FROM AUTHOR]

Give the emergence of drug resistance in bacteria resulting from antibiotic misuse, there is an urgent need for research and application of novel antibacterial approaches. In recent years, nanoparticles (NPs) have garnered significant attention due to their potential to disrupt bacteria cellular structure through loading drugs and special mechanisms, thus rendering them inactive. In this study, the surface of hollow polydopamine (HPDA) NPs was utilized for the growth of Prussian blue (PB), resulting in the formation of HPDA-PB NPs. Incorporation of Co element during the preparation process led to partial doping of PB with Co2+ ions. The performance test results demonstrated that the HPDA-PB NPs exhibited superior photothermal conversion efficiency and peroxidase-like activity compared to PB NPs. HPDA-PB NPs have the ability to catalyze the formation of hydroxyl radicals from H2O2 in a weakly acidic environment. Due to the tiny PB particles on the surface and the presence of Co2+ doping, they have strong broad-spectrum antibacterial properties. Both in vitro and in vivo evaluations confirm their efficacy against various bacterial strains, particularly Staphylococcus aureus, and their potential to promote wound healing, making them a promising candidate for advanced wound care and antimicrobial applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Plasmon-mediated chemical reaction (PMCR) is a highly attractive field of research. Here we report in situ surface-enhanced Raman spectroscopic (SERS) monitoring of plasmonic-mediated S S bond-forming reaction. The reaction is thought to be a self-coupling reaction proceeding by photoinduced aromatic S C bond arylation. Surprisingly, the S C arylation and S S coupling are found to be occurred on both partially oxidized silver and silver nanoparticles. The results demonstrated that silver oxide or hydroxide and small molecule donor sacrifice agent played a crucial role in the reaction. This work facilitates the in-situ manipulation and characterization of the active silver electrode interface in conjunction with electrochemistry, and also establishes a promising new guideline for surface plasmon resonance photocatalytic reactions on metal nanostructures with high efficiency. [ABSTRACT FROM AUTHOR]

The paper discusses the results of the electrosynthesis of metal–polymer nanocomposites of silver and coatings on pure iron and steel electrodes by combining the process of electropolymerization of 1-vinyl-1,2,4-triazole (VT) with N-vinyl-caprolactam (VC) and cathodic precipitation of metals. During the electrolysis of aqueous and water–ethanol solutions of VT with VC at various ratios in the presence of AgNO3, metal nanocomposites and coatings are formed on purely iron and steel electrodes. The structure and composition of the synthesized metal nanocomposites were confirmed by various physicochemical methods, such as electron and IR spectroscopic, X-ray phase and thermogravimetric, elemental analyses, as well as by transmission electron microscopy. In the electronic spectra of nanocomposites, absorption bands appear with a maximum at 405–421 nm, which is typical for systems with zero-valent silver. The IR spectra show that the matrix structure hardly changes during the formation of nanocomposites and coatings. At high current densities (j ≥ 10 mA/sm2), nanocomposite films are formed on the electrode surface. The silver content in nanocomposites is 0–9%, which leads to an increase in the viscosity of nanocomposite solutions compared to solutions of the initial copolymers. Increasing the silver content above 8% will lead first to a partial and then to a complete loss of solubility. According to the data of transmission electron macroscopy, the synthesized polymer nanocomposites consist of isolated silver nanoparticles, predominantly spherical in shape, uniformly distributed in the bulk of the polymer matrix. The size dispersion of nanoparticles depends on the silver content in the nanoparticles. The thermal decomposition of metal nanocomposites occurs in stages. [ABSTRACT FROM AUTHOR]

Gold and silver nanoparticles have witnessed increased scientific interest due to their colourful colloidal solutions and exceptional applications. Comparing the localized surface plasmon resonance (LSPR) of gold and silver nanoparticles is crucial for understanding and optimizing their optical properties. This comparison informs the design of highly sensitive plasmonic sensors, aids in selecting the most suitable nanoparticles for applications like surface-enhanced infrared spectroscopy (SEIRA) and biomedical imaging, and guides the choice between gold and silver nanoparticles based on their catalytic and photothermal properties. Ultimately, the study of LSPR facilitates the tailored use of these nanoparticles in diverse scientific and technological applications. Two SEIRA methods combined with partial least squares regression (PLSR) chemometric tools were developed. This development is based on the synthesis of homogeneous, high-dense deposited metal nanoparticle islands over the surface of glass substrates to be used as lab-on-chip SEIRA sensors for the determination of bisacodyl (BIS) and its active metabolite in plasma. SEM micrographs revealed the formation of metallic islands of colloidal citrate-capped gold and silver nanoparticles of average sizes of 29.7 and 15 nm, respectively. BIS and its active metabolite were placed on the nanoparticles' coated substrates to be directly measured, then PLSR chemometric modelling was used for the quantitative determinations. Plasmonic citrate-capped gold nanoparticle substrates showed better performance than those prepared using citrate-capped silver nanoparticles in terms of preparation time, enhancement factor, PLSR model prediction, and quantitative results. This study offers a way to determine BIS and its active metabolite in the concentration range 15–240 ng/mL in human plasma using inexpensive disposable glass-coated substrates that can be prepared in 1 h to get results in seconds with good recovery between 98.77 and 100.64%. The sensors provided fast, simple, selective, molecular-specific and inexpensive procedures to determine molecules in their pure form and biological fluid. [ABSTRACT FROM AUTHOR]

Silver ions are considered an antibacterial candidate for numerous applications. In this regard, different phases of nanoparticles containing silver were prepared, including silver phosphate and magnesium vanadate, to be incorporated into a polymeric blend based on polyvinyl alcohol (PVA) and hyaluronic acid (HA). These blends were cast in thin films, while different concentrations of the nanoparticles were embedded through the films to promote their adhesion features. In addition, the surface topography of the films was investigated. It was shown that the grain size of silver phosphate was around 84–300 nm, while that of magnesium vanadate was around 43–66 nm. The porosity appeared to be high on the surface. In addition, the surface roughness increased with the addition of nanoparticles. Furthermore, the Mg3(VO4)2@PVA/HA film has the most efficient antibacterial action; the inhibition zone around E. coli species was 19.5 ± 0.5 mm, while that around S. aureus was 16.0 ± 1.0 mm. Additionally, the Ag3PO4@HA film also exhibited germicidal potential; the E. coli inhibition area was 18.0 ± 1.0 mm, while that of S. aureus was 10.5 ± 0.5 mm. Finally, the effect of Ag3PO4/Mg3(VO4)2/CNT@PVA/HA was investigated on the human lung cell line. Cell viability was 81.96% and 125%, respectively, when 5000 and 4.9 g ml−1 were administered. [ABSTRACT FROM AUTHOR]

The synthesis of Cyanobacteria‐mediated nanoparticles has attracted great attention due to its ecofriendly, cost‐effective and biocompatible properties. Silver nanoparticles (AgNPs) are used in different areas such as medicine, household products, disinfectants or food storage. The present study aimed the biosynthesis of AgNPs from Cyanobacterial Chroococcus sp. and their antimicrobial activities on some important pathogen bacterial species. According to the obtained data, optimal conditions for synthesis of AgNPs were extract rate 3 : 1 v/v (cell extract/AgNO3), silver salt concentration 10 mM, pH 7, temperature 60 °C and time 30 minutes. The surface plasmon resonance peak of AgNPs was observed at 420–430 nm, and AgNPs were well‐dispersed spherical with an average size of 11–13 nm in diameter by TEM. SEM‐EDX analysis revealed a strong signal of silver. With FTIR analyzes, shift in the absorption bands after the AgNPs formation was confirmed. X‐ray diffraction analysis exhibited that the AgNPs were cubic crystalline shape. Zeta potential of AgNPs showed ‐ 20 mV. The AgNPs strong showed antibacterial activity on an opportunistic bacterial pathogens of Micococcus luteus, Bacillus subtilis and Pseudomonas aeroginosa. The effective and rapid synthesis of Chroococcus‐mediated AgNPs and their strong antimicrobial effects can create an important potential for their use in biomedical and environmental applications. [ABSTRACT FROM AUTHOR]

Indeed, considerable efforts have been made in the domain of silver nanoparticles, including the construction and wide‐ranging applications. This work involves the synthesis and characterization of salophen anchored silver nanoparticles (AgNPs), and its utilization for selective detection of Fe2+ and Cu2+ ions in DMSO. These AgNPs were synthesized by the reduction of Ag+ ions with salophen ligand, and were characterized by different techniques which include UV‐visible, fluorescence, FTIR, SEM, EDX, TEM, PXRD, DLS, and zeta potential. The negative zeta potential value of −19.6 mV evidenced the stability of the AgNPs. These AgNPs were found to sense Fe2+ and Cu2+ ions selectively in DMSO solution at various concentrations. Instant color change from olive to brown as well as olive to light olive was observed while detecting Fe2+ and Cu2+ ions by the nanoprobe, respectively. UV‐visible and fluorescence spectroscopic investigations were carried out to establish the sensing ability of the nanoprobe. Additionally, AgNPs revealed promising antibacterial activity selectively against gram‐negative bacteria over gram‐positive bacteria. Thus, our approach opens up a new track to design novel and operative functionalized nanomaterials for real‐life sensing and biomedical applications. [ABSTRACT FROM AUTHOR]

Occupational health must be strictly considered in industries particularly in nanoparticle factories where workers were exposed to different types of chemicals. We measured the serum levels of inflammatory cytokines in workers who developed skin lesions after exposure to silver and silica nanoparticles. Using a questionnaire in this cross-sectional study, we identified 110 workers in nanoparticle industries who were exposed to silver and silica nanoparticles. We also included 40 healthy subjects as controls from the administrative department of the same factories who were not exposed to nanoparticles. Peripheral blood samples used to measure the mRNA levels of inflammatory cytokines by qRT-PCR. In comparison with the control group, the workers who developed skin lesions had significantly higher levels of interleukin IL4, IL6, IL8, and TNF-α, particularly after two or three decades of exposure to silver and silica nanoparticles. Participants who were exposed to silver had higher levels of IL6 and IL8 compared with those who were exposed to silica. Necessary measures must be considered to protect workers in nanoparticle industries against the potential toxic effects of these compounds. Our network pharmacology study suggests corresponding biochemical pathways for these disorders. [ABSTRACT FROM AUTHOR]

• Eco-friendly synthesis of gold and silver nanoparticles using Solanum nigrum root extract, characterized using various techniques (XRD, UV–Vis, FTIR, TEM, SAED and EDAX). • Dose-dependent lung cancer activity is evaluated. • Environmental remediation against methylene blue and methylene orange dyes. • Antibacterial assessment targeting Salmonella typhi and Staphylococcus aureus. In this study, we utilized the natural reducing and stabilizing properties of Solanum nigrum root (SNR) to create nanoscale gold and silver particles, and explored their potential for anticancer, antibacterial, and photocatalytic applications. Natural source-based nanoparticle preparation was achieved by combining root extract with aqueous solutions of chloroauric acid and silver nitrate. The produced nanoparticles were recognized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible spectroscopy (UV–VIS), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and Energy-Dispersive X-ray spectroscopy (EDAX). Resulting nanoscale particles had diameters of 22.35 nm and 11.85 nm for gold and silver nanoparticles synthesized using a 5 ml SNR extract. While 16.06 nm and 8.72 nm sized gold and silver nanoparticles were synthesized using a 10 ml SNR extract. Their antibacterial properties were tested against Salmonella typhi and Staphylococcus aureus. Staphylococcus aureus showed the highest inhibitory activity. To evaluate the effectiveness of NPs in treating lung cancer, in vitro experiments were performed utilising the A549 cell line. The remarkable performance of gold and silver nanoparticles in the photocatalytic degradation of methylene blue and methylene orange was demonstrated. This research contributes to Solanum nigrum -derived metal nanoparticles and their multifunctional capabilities, paving the way for new prospects in cancer therapeutics, antibacterial agents, and environmental remediation strategies. [ABSTRACT FROM AUTHOR]

This work has focused on the development of a new analytical alternative based on the laser-induced breakdown spectroscopy (LIBS) technique for the fast, reliable, and economical determination of the gold and silver nanoparticle content in a low linear concentration range between 2.9 and 0.058 μg mL−1 and 2.9–0.116 μg mL−1, respectively, without requiring complicated sample pretreatment procedures or advanced separation techniques. Metallic nanoparticles are currently essential materials for the development of new technologies in different scientific and technical areas. However, numerous studies have pointed out these nanomaterials' toxic and polluting potential and the various health implications for humans, animals, and the ecosystem. The current reality reflects the lack of analytical techniques with low economic, environmental, and health impacts and the capacity to quantify the total metallic nanoparticle content. For this purpose, a novel and simple method for the selective capture of gold and silver nanoparticles, consisting of a chemically functionalized glass surface, has been custom-developed for subsequent analysis with LIBS. The results show that the proposed method, employing a functionalized sample glass support, presents a suitable analytical performance characterized by increased sensitivity, specifically 4.7% and 329.2% for Au-NPs and Ag-NPs, and proportionally decreased error in the slope and intercept of the calibration curves, 68% for Au-NPs and 87% for Ag-NPs, respectively. [ABSTRACT FROM AUTHOR]

Single-cell analysis using inductively coupled plasma mass spectrometry (SC-ICP-MS) is an analytical methodology that allows to obtain qualitative and quantitative information of the element content of bioparticles (cells, bacteria, unicellular algae, yeasts...) on a cell-by-cell basis. In this study, two commercially available nebulisation systems for introduction of intact bioparticles were evaluated, showing similar performance. Bacteria (E. coli) exposed to Ag(I) and 10 nm Ag nanoparticles were detected and their complete silver content distributions successfully recorded. Analysis of the corresponding spheroplasts, obtained after enzymatic digestion of the bacterial outer membrane with lysozyme, allowed information about the intracellular silver to be obtained, providing an insight into the biodistribution of silver in the bacteria. Likewise, validity of the quantitative information obtained by SC-ICP-MS was evaluated by applying methodology based on the estimation of silver mass per bioparticle critical values and successive dilutions. The quantitative information obtained by SC-ICP-MS for the total content of silver in bacteria and spheroplasts was confirmed by acid digestion followed by conventional ICP-MS analysis. Bacteria exposed to silver nanoparticles accumulated lower amounts of silver than those exposed to ionic silver, the latter being totally internalized, showing the higher bioavailability of ionic silver. This study proves for the first time the suitability of SC-ICP-MS for the quantitative determination of silver in bacteria, as well as in spheroplasts when combined with lysozyme digestion. Limits of detection of 7 ag of Ag per bioparticle, 500 bioparticles per mL and 38 ng of total Ag per litre of bacteria/spheroplast suspension were achieved. [ABSTRACT FROM AUTHOR]

This investigation aims to synthesize, analyze the molecularity, and test the ability of bacterial inhibition capability of silver nanoparticles that have been synthesized by simply mixing silver nitrate and aqueous extracts of marine natural products with and without the addition of amylum as a stabilizing agent. This research, with and without the addition of amylum as a stabilizing agent, obtained 39.0 and 55.2 mg of solids of round-shaped morphology silver nanoparticles with diameters of 87.9 and 103.0 nm., respectively. In addition, the antibacterial testing assay against Staphylococcus aureus and Escherichia coli showed some considerably good results. S. aureus with the addition of amylum had inhibition zone diameters of 8.55 and 7.45 mm, whereas without the addition of amylum had inhibition zone diameters of 7.82 and 7.22 mm. E. coli with the addition of amylum had inhibition zone diameters of 7.0 and 7.65 mm, whereas E. coli without the addition of amylum had inhibition zone diameters of 7.82 and 7.22 mm. [ABSTRACT FROM AUTHOR]

Nanocomposites based on silver nanoparticles and chitosan present important advantages for medical applications, showing over time their role in antibacterial evaluation. This work presents the comparative study of two chemical synthesis procedures of nanocomposites, based on trisodium citrate dihydrate and sodium hydroxide, using various chitosan concentrations for a complex investigation. The nanocomposites were characterized by AFM and DLS regarding their dimensions, while FT-IR and UV–VIS spectrometry were used for the optical properties and to reveal the binding of silver nanoparticles with chitosan. Their antibacterial effect was determined using a disk diffusion method on two bacteria strains, E. coli and S. aureus. The results indicate that, when using both methods, the nanocomposites obtained were below 100 nm, yet the antibacterial effect proved to be stronger for the nanocomposites obtained using sodium hydroxide. Furthermore, the antibacterial effect can be related to the nanocomposites' sizes, since the smallest dimension nanocomposites exhibited the best bacterial growth inhibition on both bacteria strains we tested and for both types of silver nanocomposites. [ABSTRACT FROM AUTHOR]

Biofilms are a common cause of nosocomial infections that often attack hospitalized patients. The main objective of this study was to examine the efficacy of silver nanoparticles-temu giring rhizomes in combating bacteria and preventing biofilm formation. The antibacterial and antibiofilm properties of these nanoparticles were evaluated against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The research began with the extraction of temu giring rhizome, synthesis of silver nanoparticles-temu giring rhizome, disk diffusion test, biofilm formation inhibitory activity test, and characterization of silver nanoparticles-temu giring rhizome. In this research, silver nanoparticlestemu giring rhizome were utilized at concentrations of 10, 20, 40, 80, 160 μg/ ml, and a control in the form of chlorhexidine. The results showed that the silver nanoparticles-temu giring rhizome produced a larger inhibition zone for bacterial growth compared to the control against the three bacteria. The IC50 value of silver nanoparticles-temu giring rhizome required to inhibit biofilm formation was 27.64 μg/ml in E. coli, 29.29 μg/ml in P. aeruginosa, and 26.21 μg/ ml in S. aureus. In P. aeruginosa, E. coli, and S. aureus, the IC50 for preventing biofilm formation by silver nanoparticles-temu giring rhizome was determined to be 27.64 μg/ml, 29.29 μg/ml, and 26.21 μg/ml, respectively. Evaluation of silver nanoparticles revealed the success of temu giring rhizomes in reducing silver ions. This is shown that silver nanoparticles-temu giring rhizomes can be developed into active ingredients that inhibit the growth of bacteria that cause nosocomial infections. [ABSTRACT FROM AUTHOR]

Polyethylene glycol-6000 (PEG-6000) and trisodium citrate dihydrate (TSC) form an aqueous two-phase system (ATPS). This ATPS has been explored for synthesis and separation of silver nanoparticles (AgNPs). However, synthesis of stable nanoparticles using high TSC concentration corresponding to generic ATPS composition is not possible as high ionic strength of TSC causes aggregation and precipitation of silver nuclei. In the current study, this problem was overcome by synthesizing AgNPs at low concentrations of TSC. A two-step process was used for simultaneous synthesis and separation of AgNPs. Once stable nanoparticles were synthesised at low TSC concentration, the solution was taken to biphasic ATPS composition by mixing higher concentrations of TSC and PEG-6000 solutions to ensure particle entrapment. A silver to TSC (Ag+:TSC) molar ratio ≥ 67 × 10–3 that corresponds to lower TSC concentrations resulted in the formation of stable silver nanoparticles. The synthesis was carried out in batch and continuous modes. Spherical particles of average size 9.1 ± 3.4 nm were obtained in batch mode while in the continuous mode, the size was 10.6 ± 2.5 nm. Addition of polyvinylpyrrolidone (PVP) helped in sterically stabilizing the particles. Spontaneous formation and stabilization of AgNPs were observed within 15 min of reaction time as opposed to several hours reported in literature. The adopted synthesis route thus, is an effective green process to synthesise stable nanoparticles of silver which can be used in biological applications. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNP) can help prevent infection of virus and bacteria. The size and morphology of AgNP can be crucial to function, with smaller nanoparticles (< 20 nm) able to penetrate the cell wall. This is significant as oxidative stress and genotoxicity are associated with some sizes and coatings of AgNP, contraindicating the use of AgNP to reduce infection. We present evidence that a microfluidic chip can synthesize larger sizes and distributions of AgNP from the nano-to-micro size range. We show results from a microfluidic mixing chip that can produce a wide range of nano-to-micro size (~ 24–400 nm) AgNP. Synthesis is based on a modified Turkevich method, using a single-step AgNP synthesis on the microfluidic chip using two chemical components, trisodium citrate (NaCit) and AgNO3. To make AgNP more accessible, we describe the microfluidic chip and conditions capable of synthesis. We also describe how modification of flow rate and chemical reagent concentration change particle diameter during production. In our experiments, we found that AgNP production created a visible adsorption line in the microfluidic device, possibly owing to AgNP surface interaction at the polydimethylsiloxane (PDMS) interface. We characterize these particles with dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Based on optical light microscopy, we hypothesize that AgNP formation primarily occurs at the interface between the two chemical reagent streams. We also conclude that AgNP size increases could be due to interaction with the PDMS surface, which is known to be porous. Future work will help to understand how surface interaction may influence the formation of larger particles. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (Ag-Nps) were grown on the surface of a p-type crystalline silicon (C-Si) substrate using electroless metal deposition. It was found that the Ag-Nps distribution on C-Si was controlled by the silver nitrate (AgNO3) concentrations. Atomic force microscopy observations revealed the formation of a continuous layer at high concentration. In contrast, a distribution of Ag-Nps with a spherical shape was obtained at lower concentration. The samples were also examined by optical microscopy under dark field illumination. The light reflected from Ag-Nps was obtained with different colors. This difference indicates a slight change in particle size. It is demonstrated that a silicon substrate with deposited Ag-Nps shows a significant decrease in reflectance and an increase of the absorption in the region from 200 to 800 nm. Moreover, the behavior of small Ag-Nps while interacting with light (absorbed or scattered light) is theoretically described using the Mie theory based on the Drude model. The introduction of silver nanoparticles on silicon surface is used to improve the efficiency of solar cells by reducing reflection and increasing the light absorption. [ABSTRACT FROM AUTHOR]

The combination of ultrasound and microreactors for the synthesis of nanomaterials is becoming increasingly popular, but effectively altering the ultrasonic field at the microscale to control the crystallization process remains a challenge. Herein, we investigated numerically and experimentally the effects of the ultrasonic field on the synthesis of boron-doped carbon nitride supported silver nanoparticles based on our homemade ultrasound-assisted coiled flow inverter microreactor (UCFIR). Specifically, the ultrasound promotes the radial mixing in the coiled flow inverter microreactor, even under low Reynolds number 10, resulting in better control over the crystallization process. The effects of key parameters, such as ultrasonic field distribution and ultrasonic power, on the particle size and size distribution of Ag/B-g-C3N4 have been demonstrated. The results show that when the ultrasound transducer is positioned on the 'abc' sides, the Ag/B-g-C3N4 with small and uniform Ag particles (4.12 ± 1.12 nm) can be obtained. As ultrasound power increased (0–176 W) and residence time decreased (17.5–140 s), the size of silver nanoparticles decreased, and their distribution narrowed. [ABSTRACT FROM AUTHOR]

New silver complexes [Ag(bipy)(CH3COCHCOR)]x with 2,2′-bipyridine (bipy) and β-diketonate ligands (tfac: R = CF3, x = 2; hfbac: R = C3F7, x = 1) are prepared as part of the search for precursors for the vapor deposition of films and silver nanoparticles. The compounds are characterized by elemental analysis, IR and 1H NMR spectroscopy; their crystal structures are determined by XRD. Both complex are molecular due to the bidentate-cyclic coordination of both ligands. The [Ag(bipy)(hfbac)] molecules are mononuclear due to the steric effect of the extended perfluoroalkyl chain. For L = tfac, a binuclear complex is formed due to the coordination of the methine carbon atom. Thermal properties of the new complexes are studied by TGA and DSC and compared with those of the known hexafluoroacetylacetonate analog [Ag(bipy)(hfac)]2. The temperatures and thermodynamic parameters of melting are determined for all the studied compounds. [ABSTRACT FROM AUTHOR]

Multifunctional and biodegradable dressings with high mechanical strength and good antibacterial activity are crucial in fundamental health services. This study was initiated to prepare a novel curative wound dressing film consisting of natural biodegradable gelatin (G) and polylactic acid (PLA) with silver nanoparticles (AgNPs) where glutaraldehyde (GA) was used as compatibilizer. The prepared composite films addressed the poor thermal and biological stability of G and the limited fluid retention capacity of PLA. Silver nanoparticles were prepared by basic chemical reduction and reinforced on polymer films using simple solvent casting, which obviated common clinical infections and accelerated wound closure rate (p <.05). Fourier transform infrared (FTIR) studies confirmed composite formation through H-bonding and X-ray diffraction (XRD) revealed increased crystallinity due to incorporating AgNPs. Films with G, PLA & GA (50:50:5 by volume) introduced the best elasticity & strength with excellent fluid retention properties (p <.05). Scanning electron microscopy (SEM) images unfolded surface morphology and presence of agglomerated AgNPs on film surfaces. Prepared films exhibited significant antimicrobial efficacy against Staphylococcus aureus and Pseudomonas sp. and showed excellent cell viability (>97 %) in Vero cell line. Finally, an in vivo mouse model study showed 99.7 % contraction (p <.05) within 12 days, which was most effectual and 12 % faster than conventional gauge bandages. These results demonstrated the promising and cost-effective potential of the prepared film for wound healing. [ABSTRACT FROM AUTHOR]

In response to the persistent challenge of heavy and noble metal environmental contamination, our research explores a new idea to capture silver through porous spherical silica nanostructures. The aim was realized using microwave radiation at varying power (P = 150 or 800 W) and exposure times (t = 60 or 150 s). It led to the development of a silica surface with enhanced metal-capture capacity. The microwave-assisted silica surface modification influences the notable changes within the carrier but also enforces the crystallization process of silver nanoparticles with different morphology, structure, and chemical composition. Microwave treatment can also stimulate the formation of core–shell bioactive Ag/Ag2CO3 heterojunctions. Due to the silver nanoparticles' sphericity and silver carbonate's presence, the modified nanocomposites exhibited heightened toxicity against common microorganisms, such as E. coli and S. epidermidis. Toxicological assessments, including minimum inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50) determinations, underscored the efficacy of the nanocomposites. This research represents a significant stride in addressing pollution challenges. It shows the potential of microwave-modified silicas in the fight against environmental contamination. Microwave engineering underscores a sophisticated approach to pollution remediation and emphasizes the pivotal role of nanotechnology in shaping sustainable solutions for environmental stewardship. [ABSTRACT FROM AUTHOR]

This study focuses on tumor therapy using two biocompatible silver nanoplatforms of chamomile extract and its active ingredient apigenin-7-glucoside. Chamomile silver nanoparticles (Ch-AgNPs) and apigenin 7- glucoside silver nanoparticles (Ap-AgNPs) were synthesized and characterized using different analytical techniques. On a stable nanoplatform with spherical nanoparticles in a narrow size range, both Ch-AgNP and Ap-AgNP exhibit potent cytotoxic effects against two different cell lines (HepG2 and MCF7). The synthesized NPs were radiolabeled with 131I giving high radiochemical purity. Biodistribution studies in tumor-bearing Albino mice showed higher accumulation in tumor sites compared to normal muscle. In conclusion, after further preclinical studies, both chamomile silver nanoparticles (Ch-AgNPs) and apigenin-7-glucoside silver nanoparticles (Ap-AgNPs) can be used as potential drugs for tumor theranostics. [ABSTRACT FROM AUTHOR]

Selective and sensitive detection of halides in water is critically important in the diagnosis of diseases and assessment of aquatic ecosystems. The recognition is usually carried out by numerous analytical techniques such as ion chromatography, fluorescence, near-infrared spectroscopy, ion-selective electrode and light scattering. Although these methods offer high sensitivity, they are expensive and time-consuming. Therefore, great efforts have been focused on the sensing of halide anions in water through a simple, fast, low-cost and portable paper-based colorimetric platform. In particular, the sensing process with silver nanoparticles interacting with analytes is of great chemical and biological interest. In this work, anisotropic silver nanoparticles in size and shape embedded in epoxy resin were prepared and subsequently printed on filter papers of cellulose. The influence of water and halide anions (Cl−, Br− and I−) on the morphology of these nanoparticles are investigated by scanning electron microscopy, Raman shift and diffuse reflectance spectroscopy. The mechanism involves aggregation of faceted silver nanoparticles induced by interactions between carbonyl groups of the resin and water. Subsequently, the interaction between halide anions and the aggregated silver nanoparticles causes oxidative etching on their surface, shape conversion (faceted to quasi-spherical shapes), decreasing in the particle size and formation of chain–like or compact aggregates resulting in strong interparticle plasmonic coupling. This selective mechanism was tested for the naked-eye colorimetric recognition of chloride anions in a complex simulated physiological system, whose results show promising perspectives to develop diagnostic-sensing devices. [ABSTRACT FROM AUTHOR]

Background: Skin grafting is a helpful instrument in a plastic surgeon's arsenal. Several types of dressings were designed to facilitate the process of graft integration. Negative-pressure wound therapy is a proven dressing method, enhancing graft survival through several mechanisms: aspiration of secretions, stimulation of neoangiogenesis, and promotion of an anti-inflammatory environment. Silver nanoparticle dressings also bring multiple benefits by bearing an antimicrobial effect and providing a humid medium, which are favorable for epithelialization. The combination of NPWT (negative-pressure wound therapy) with AgNPs (silver nanoparticles) has not been widely studied. Materials and methods: This study aimed to compare the outcomes of silver nanoparticle sheets with the combination of negative-pressure wound therapy and silver nanoparticle dressings. We conducted a comparative prospective study on 80 patients admitted to the Plastic Surgery Department of "Prof. Dr. Agrippa Ionescu" Emergency Clinical Hospital between 1st of January 2020 and 31st of December 2022. The study population was randomized to receive either silver nanoparticle dressings or negative-pressure wound therapy (NPWT) combined with silver nanoparticle dressings. Various parameters were monitored, including patient comorbidities and graft-related data such as defect etiology, graft integration, and graft size. Dressings were changed, and graft status was evaluated at 7, 10, and 14 days postoperatively. Additionally, baseline C-reactive protein (CRP) levels were measured before surgery and 7, 10, and 14 days postoperatively. Results: The study demonstrated an enhanced integration of skin grafts at all evaluation stages when employing NPWT combined with AgNPs, particularly evident 10 days post operation. Significant variations in graft integration were also observed based on factors such as diabetes, cardiovascular disease, graft size, or the origin of the grafted defect. Moreover, dynamic C-reactive protein monitoring showed a statistically significant decrease in CRP levels 10 days post operation among patients treated with NPWT in conjunction with silver dressing, consistent with the nearly complete integration of skin grafts at this evaluation threshold. Conclusion: Several factors influence the postoperative evolution of split-skin grafts. Postoperative dressings target local factors to enhance graft integration further. Our research demonstrated that the innovative combination of NPWT-assisted dressings, complemented by a silver nanoparticle sheet, resulted in improved benefits for graft integration and the alleviation of systemic inflammation. [ABSTRACT FROM AUTHOR]