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ZnO/g-C3N4 heterojunction modified with Ag nanoparticles (ZnO/CN/Ag) was synthesized by depositing ZnO nanorods/Ag nanoparticles onto g-C3N4 nanosheets. Under xenon lamp irradiation, 99% of Rhodamine B (RhB) was degraded by ZnO/CN/Ag-5% composite within 30 min, which was much higher than the degradation efficiency of ZnO and ZnO/CN. The synergistic effect of g-C3N4 and ZnO, along with the localized surface plasmon resonance effect of Ag NPs, contributes to the improvement of photocatalytic performance. Ag nanoparticle provides another charge transfer path from g-C3N4 to ZnO, which speeds up the separation of electron–hole pairs. Meanwhile, the catalyst had good stability and recyclability. Finite-difference time-domain method and the density functional theory were used to obtain the charge transfer process. The photodegradation process has been studied in depth. [ABSTRACT FROM AUTHOR]

Due to their high similarity to biological ion channels, low power consumption, small footprint, and the fact that they do not require reset circuits, threshold switching memristors have been intensively studied for simulating neurons in neuromorphic chips. Switching speed is one of the key challenges which limit the application of threshold switching memristors in chips. In this study, Ta2O5 threshold switching memristors with high switching speeds were prepared by doping with silver. The results show that 14 wt. % Ag doped Ta2O5 threshold switching memristors exhibit excellent bi-directional threshold switching performance, featuring fast switching speeds (<20 ns, <18 ns), low leakage currents (<10 pA), and high switching ratio (>107). According to the field nucleation theory, the rapid switching speed can be attributed to the low nucleation energy (0.26 eV) of silver within the Ta2O5 matrix, which is achieved by incorporating 14 wt. % Ag during the doping process. Based on Pspice, a LIF (leaky integrate-and-fire) neuron based on the silver nanoparticles doped Ta2O5 threshold switching memristors is built, and its firing function has been simulated. The results show that the LIF neuron with a short switching time is able to excite pulse spiking with high frequencies. These results demonstrated that the silver nanoparticles doped Ta2O5-based threshold switching memristors hold significant potential for constructing high-speed artificial neural networks. [ABSTRACT FROM AUTHOR]

Grafting nanomaterials on the carbon fiber (CF) surface is considered an effective strategy for enhancing the interfacial properties of CF-reinforced polymer composites (CFRPs). However, the mechanical properties of the CFs are often compromised during treatment. A new method for in situ growing silver nanoparticles (AgNPs) on the CF surface is proposed in this study. The CFs are first immersed in a low-viscosity silver nitrate solution to form a thin liquid film on the surface. Subsequently, using the abundant active particles in the plasma, the silver ions are reduced to silver atoms and grown into AgNPs on the CF surface. The tensile strength of CF@Ag was 38.74% greater than that of untreated CF, potentially due to the reparative action of AgNPs on defects in CF. The CF showed an evident improvement in surface wettability because of the AgNPs. Furthermore, the interfacial properties were noticeably improved, with the interfacial shear strength of CF@Ag increasing to 91.59 MPa, which was about twice that of pristine CF. Thus, the mechanical properties of composites are significantly improved (flexural strength increased by 190.74%). This study presents a non-destructive and convenient method for growing nanoparticles onto CF to establish a robust interface in CFRPs. [ABSTRACT FROM AUTHOR]

A combination of experimental and numerical investigations on metallic silver and platinum nanoparticles deposited on silica substrates is presented, with a focus on metal–substrate interactions. Experimentally, the nanoparticles, obtained by ultra-high vacuum atom deposition, are characterized by grazing-incidence small-angle x-ray scattering and high resolution transmission electronic microscopy to determine their structure and morphology and, in particular, their aspect ratio (height/diameter), which quantifies the metal–substrate interaction, from the as-grown to equilibrium state. Numerically, the interactions between the metal and the silica species are modeled with the Lennard-Jones (12, 6) potential, with two parameters for each metal and silica species. The geometric parameters were found in the literature, while the energetic parameters were determined from our experimental measurements of the aspect ratio. The parameters are as follows: σAg–O = 0.278 nm, σAg–Si = 0.329 nm, ɛAg–O = 75 meV, and ɛAg–Si = 13 meV for Ag–silica and σPt–O = 0.273 nm, σPt–Si = 0.324 nm, ɛPt–O = 110 meV, and ɛPt–Si = 18 meV for Pt–silica. The proposed Ag–silica potential reproduces quantitatively the unexpected experimental observation of the variation of the aspect ratio for Ag nanoparticles larger than 5 nm, which has been interpreted as a consequence of the silica roughness. The nanoparticle orientation, structure, and disorder are also considered. This metal–silica potential for Ag and Pt should be helpful for further studies on pure metals as well as their alloys. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the biocompatibility of silver nanoparticle (AgNP)-doped Ti-6Al-4V surfaces by evaluating the viability and proliferation rate of human gingival fibroblasts (HGFs)--as the dominant cells of peri-implant soft tissues-- seeded on the modified surfaces. Materials and Methods: AgNPs (sizes 8 nm and 30 nm) were incorporated onto Ti-6Al-4V specimen surfaces via electrochemical deposition, using colloid silver dispersions with increasing AgNP concentrations of 100 ppm, 200 ppm, and 300 ppm. One control and six experimental groups were included in the study: (1) control (Ti-6Al- 4V), (2) 8 nm/100 ppm, (3) 8 nm/200 ppm, (4) 8 nm/300 ppm, (5) 30 nm/100 ppm, (6) 30 nm/200 ppm, and (7) 30 nm/300 ppm. HGF cell primary cultures were isolated from periodontally healthy donor patients and cultured in direct contact with the group specimens for 24 and 72 hours. The cytotoxicity of AgNP-doped Ti-6Al-4V specimens toward HGF was assessed by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) and BrdU (5-bromo-2'-deoxyuridine) assay tests. Calcein AM and ethidium homodimer (EthD-1) fluorescent stains were used to determine the live and dead cells. The morphology and attachment properties of the HGFs were determined via scanning electron microscopy (SEM). Results: Energy dispersive x-ray (EDX) analysis confirmed the presence of AgNPs on the specimens. The MTT test revealed that AgNPs of both sizes and all concentrations presented a decreased cellular metabolic activity compared to the control discs. All concentrations of both sizes of AgNPs affected the cell proliferation rate compared to the control group, as revealed by the BrdU assay. Overall, cytotoxicity of the modified Ti-6Al-4V surfaces depended on cell exposure time. Observation via confocal microscopy confirmed the results of the MTT and BrdU assay tests. Specifically, most cells remained alive throughout the 72-hour culture period. SEM images revealed that adjacent cells form bonds with each other, creating confluent layers of conjugated cells. Conclusions: The findings of the present study indicate that Ti-6Al-4V surfaces modified with 8 nm and 30 nm AgNPs at concentrations of 100 ppm, 200 ppm, and 300 ppm do not produce any serious cytotoxicity toward HGFs. The initial arrest of the HGF proliferation rate recovered at 72 hours. These results on the antibacterial activity against common periodontal pathogens, in combination with the results found in a previous study by the same research group, suggest that AgNP-doped Ti-6Al-4V surfaces are potential candidates for use in implant abutments for preventing peri-implant diseases. [ABSTRACT FROM AUTHOR]

Enantio-discrimination and spin-dependent electrochemistry (SDE), as a manifestation of the chirality-induced spin selectivity (CISS) effect, are important phenomena that can be probed by "chiral" electrochemistry. Here, we prepared chiralized surfaces of gold and nickel, to serve as working electrodes, through effective chemisorption of enantiopure dimethyl-bis(ethylenedithio)-tetrathiafulvalene (DM-BEDT-TTF) 1, tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) 2, and their capped silver nanoparticle (AgNPs) aggregate by simple incubation of the metallic substrates. The effective chemisorption was checked by means of ultrahigh vacuum x-ray photoelectron spectroscopy (XPS) and by electro-desorption experiments, i.e., cyclic voltammetry (CV) scans showing a first electro-desorption peak at about −1.0 V. The Au|1 and Au|2 chiral electrodes were successfully used in CV experiments exploiting chiral redox probes. Finally, the hybrid interfaces Ni|enantiopure 1 or 2|AgNPs served as working electrodes in SDE experiments. In particular, the hybrid chiral interfaces Ni|(R)-2|AgNPs and Ni|(S)-2|AgNPs exhibited a significant spin-filtering ability, as a manifestation of the CISS effect, with average spin polarization values of 15%. [ABSTRACT FROM AUTHOR]

In this study, silver nanoparticles (AgNPs) were fabricated at room temperature using Grewia asiatica leaf extract. Photocatalytic activity (degradation of organic dye) and biological activities (antibacterial, anti-inflammatory, and anti-arthritic) of AgNPs were also unveiled. The optical and physicochemical properties of silver nanoparticles were characterised using UV-Visible spectrophotometer, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning electron microscopy (FESEM) analysis, and Dynamic light scattering (DLS) techniques. The green synthesis was justified using UV-visible spectroscopy. XRD confirmed the crystalline structure of AgNPs. The reducing and capping nature of leaf extract was explained by FTIR. The relative capping of AgNPs was studied using FESEM. The hydrodynamic size and polydispersity index of the fabricated silver nanoparticles were analysed using DLS. The photocatalytic activity of AgNPs was observed over crystal violet dye under visible light resulting in efficient removal. AgNPs were also employed to biological activities indicating good antibacterial activity (against gram-positive and gram-negative bacteria), efficient anti-inflammatory activity, and excellent anti-arthritic activity. This work explains the various applications of AgNPs: an efficient photocatalyst as well as a biomedical weapon. [ABSTRACT FROM AUTHOR]

Lead (Pb) is one of the major heavy metal pollutants that can cause serious health problems to humans and the environment. This indicates that its concentration should be known to learn its levels in various environmental systems, and a powerful and economical analytical technique should be there to do so. In this study we report a simple, rapid, cost-effective and environmentally friendly colorimetric sensor based on biosynthesised AgNPs using Parthenium hysterophorus leaf extract. The biosynthesised AgNPs were characterised by UV-vis, FTIR, XRD, SEM and EDS techniques. These nanoparticles were utilised to develop colorimetric sensor for Pb(II) detection. The developed AgNPs-based colorimetric sensor was sensitive and selective towards Pb(II) with the limit of detections of 2.8 and 0.08 µM by visual and UV-vis detection techniques, respectively. The method also exhibited excellent linearity (R2 = 0.9959) within 0.5 to 100 µM concentration range and precision (intra-day and inter-day %RSD values were 2.78% and 3.40%, respectively). The practical application of the developed AgNPs-based sensor was investigated for colorimetric detection of Pb(II) in various real-world samples such as wastewater effluents, leakage, fresh water, tap water and soft drink. The percent recoveries of the tested samples ranged from 99.5–108% indicating the potential applicability of the technique. In general, the nano-sensor is green, exhibited a potential sensitivity and applicability, and hence, recommended for the detection of Pb(II) ions in various water samples. [ABSTRACT FROM AUTHOR]

Aflatoxins are secondary metabolites produced by certain filamentous fungi such as Aspergillus flavus and may pose severe risks to human health. The presence of aflatoxins in commercial food products such as pistachio can bring severe economic drawbacks during harvest, production, and exportation. This study aimed to reduce aflatoxin levels in raw pistachio by active food packaging film enriched with silver nanoparticles and quinoa peptides and extend the shelf-life. The pistachios contaminated with Aspergillus flavus were packaged in a nanocomposite film enriched with silver nanoparticles, quinoa peptide with antifungal properties, and low-density polyethylene at varying percentages. Then, all samples were stored at 25°C for 30 days. The amount of Aflatoxin B1 and total aflatoxin (B1, B2, G1, and G2) were measured with high-performance liquid chromatography. The results showed that the percentage of film composition and time significantly affected aflatoxin values during storage (P < 0.05). The control sample had the highest amount of aflatoxins, while the sample was packaged with a film containing 35% silver nanoparticles, and the quinoa peptide had the lowest amount of aflatoxin at the end of the storage period. Based on the results obtained, the combined use of silver nanoparticles and quinoa peptides in pistachio packaging reduced aflatoxins and increased the shelf life of raw pistachio. [ABSTRACT FROM AUTHOR]

In this work, we describe a simple strategy for the preparation of a low-cost electrode material based on polypyrrole (PPy) film grown on an insulating cellulosic paper substrate via in-situ oxidative polymerisation technique and functionalised by silver nanoparticles (AgNPs) uniformly dispersed on its surface. The properties of the obtained AgNPs-PPy composites were characterised using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. The electrocatalytic activity of the prepared electrode was investigated for the electroreduction of nitrate using cyclic voltammetry in 0.1 M KOH solution. Results demonstrated that the incorporation of AgNPs into the PPy matrix improves significantly the catalytic behaviour of this film. The effect on the electrode response of the amount of the incorporated AgNPs was also investigated. This paper highlights a simple procedure for the making of low-cost paper electrodes for the efficient reduction of nitrates. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) represents a substantial global health burden, necessitating advancements in diagnostic and therapeutic modalities. This study aimed to investigate the potential of CeO2/GO nanoparticles (NPs) in managing CRC and to compare their efficacy with Ag-doped CeO2 (CeO2:Ag) NPs. The synthesis of cerium oxide (CeO2) and graphene oxide (GO) was meticulously performed, followed by a comprehensive evaluation of NPs' toxicity and their impact on apoptosis-related genes in CRC cells. Characterization techniques, including XRD, EDX, SEM, TEM, FT-IR, and DLS, validated the successful synthesis and unique properties of CeO2:Ag/GO NPs. XRD confirmed the CeO2 and GO structures, while EDX analysis confirmed high purity in the synthesized NPs and uniform element distribution in CeO2/GO NPs. SEM and TEM micrographs illustrated CeO2 NPs attached to graphene sheets, showcasing reduced size post-attachment. FT-IR revealed characteristic peaks for CeO2 and GO, confirming their composite structure. DLS showed an average NP size of 20 nm in solution. Notably, MTT assays demonstrated that CeO2:Ag/GO NPs exhibited enhanced cytotoxicity against CRC cells (C-26 cell line) compared to CeO2:Ag NPs, with higher doses showing heightened efficacy. CeO2:Ag/GO NPs induced stronger growth inhibition and apoptosis in CRC cells, which was linked to their improved cellular uptake and ability to target multiple cancer-related pathways. In contrast, GO NPs alone lacked cytotoxic effects. Gene expression analysis via qPCR revealed CeO2:Ag/GO NPs significantly downregulated Zeb-1, VEGF, Cyclin-D1, and Twist compared to controls, altering cancer-related pathways more effectively than CeO2:Ag NPs. Additionally, CeO2:Ag/GO NPs significantly upregulated BAX and Caspase-1 while downregulating Bcl-2, implicating a more potent apoptotic response. This study highlights the advantage of CeO2:Ag/GO NPs over CeO2:Ag NPs in impeding CRC cell growth and inducing apoptosis, offering a promising foundation for innovative therapeutic strategies. [ABSTRACT FROM AUTHOR]

Recent advancements in biomedical applications have highlighted the need for nontoxic and organic materials with versatile capabilities. Silver nanoparticles (AgNPs) have emerged as a promising antimicrobial agent due to their exceptional physicochemical properties, whereas hydrogels offer potential applications in biomedicine due to their biocompatibility, biodegradability, and hydrophilicity. AgNPs‐infused hydrogel can offer synergistic approach for various biomedical applications, specifically in wound healing, drug delivery, and antimicrobial coatings. The incorporation of AgNPs into the hydrogel enhances their antimicrobial properties, making them ideal for reducing infections and promoting tissue regeneration. Furthermore, AgNPs‐infused hydrogel can serve as controlled‐release systems for therapeutic agents, which ensures sustained and targeted drug delivery. Most importantly, this type of system offers a potential pathway for overcoming the challenges posed by traditional materials. While AgNPs‐infused hydrogel offer significant advantages for various biomedical applications, challenges such as potential cytotoxicity, environmental concerns, and long‐term effects require further investigation. Overall, this review comprehensively explores the synthesis methods, properties, applications, and challenges associated with AgNPs‐infused hydrogel. [ABSTRACT FROM AUTHOR]

Biocompatible nanobiocomposites, made of a biopolymer matrix reinforced with inorganic or organic fillers in nanodimensions, are used in food packaging to preserve food and extend its shelf life through their antibacterial qualities. And they reduce and resolve biological problems. This work examined the mechanical and antibacterial characteristics of a starch nanobiocomposites supplemented with silver metal nanoparticles and salvia plant extract. Using the casting procedure, samples containing salvia plant extract and silver nanoparticles at concentrations of 0.5%, 1%, 1.5%, and 2% were created, and antibacterial tests were performed on the microorganisms, Escherichia coli and Staphylococcus aureus, to test their mechanical characteristics such as thickness, tensile test, swelling, water vapor transmission, and the transmission and absorption of visible and ultraviolet light. The enhanced intermolecular interaction between the starch matrix, salvia extract, and silver nanoparticles was shown by the FTIR spectra. The distribution of nanoparticles in the nanobiocomposite film is clearly visible in the SEM pictures. The results of this study demonstrated that nanobiocomposite films made of starch, silver, and salvia extract nanoparticles had better mechanical qualities and were more successful in preventing bacterial growth than pure starch films. This finding is supported by the possibility of using biocomposite films in antimicrobial food packaging. [ABSTRACT FROM AUTHOR]

Nanomaterials are promising alternatives to antibiotics with the potential to handle the menace of emerging multidrug resistance in pathogenic microbes. We report a simple biosynthetic approach to prepare Ag nanoparticles (NPs) with strong antibacterial and antifungal actions by using Piper nigrum fruit extract as a bioreducing agent. The biosynthesized material was characterized by SEM, AFM, TEM, HRTEM, XRD and UV–Visible absorption spectroscopy. SEM, AFM and TEM analyses provided evidence that the average diameter of the Ag NPs was 18 nm, while XRD and HRTEM confirmed the FCC structure of Ag NPs. The biosynthesized Ag NPs demonstrated extremely strong antibacterial activity against Bacillus oceanisediminis and Escherichia coli, and showed extremely strong antifungal action against Schizosaccharomyces pombe, inhibiting their growth at very low concentrations of 3 μ g/mL, 4 μ g/mL and 3 μ g/mL, respectively. The molecular origin of their antibacterial and antifungal activity was studied using various molecular and biochemical assays. The results of these assays revealed a major role for reactive oxygen species (ROS) in the antifungal and antibacterial actions of the biosynthesized Ag NPs. Furthermore, morphological changes in cells and cell wall damage upon Ag NP treatment were observed by scanning electron microscopy. In addition, significant enhancement in protein leakage and fragmentation of DNA was also observed upon treatment of S. pombe, B. oceanisediminis and E. coli with Ag NPs. In conclusion, the observed extremely strong antibacterial and antifungal activities of biosynthesized Ag NPs are due to the oxidative stress triggered by ROS, causing cell wall damage and subsequent protein leakage and DNA fragmentation. We report simple biosynthesis of Ag nanoparticles with strong antibacterial and antifungal actions by using Piper nigrum fruit extract as a bioreducing agent. The biosynthesized Ag nanoparticles demonstrated extremely strong antibacterial activity against Bacillus oceanisediminis and Escherichia coli, and showed extremely strong antifungal action against Schizosaccharomyces pombe, inhibiting their growth at 3, 4 and 3 μ g/mL, respectively. Molecular and biochemical assays revealed major role for Reactive Oxygen Species, while SEM revealed cell wall damage upon Ag nanoparticle treatment. [ABSTRACT FROM AUTHOR]

This study was focused on the design and development of a new heterogeneous catalyst based on polyester (PE) fabric modified with graphene oxide nanosheets decorated with silver metallic nanoparticles (PE-rGO/Ag0), using a simple, easy, and effective approach. PE fabrics were coated by sonication with graphene oxide (GO) nanosheets followed by in situ deposition and reduction of silver nanoparticles over the GO surface, covering the PE fabric and producing PE-rGO/Ag0. The crystalline structure, surface morphology and chemical characteristics of the synthesised materials were identified by X-ray diffraction spectroscopy, scanning and transmission electron microscopy analyses (SEM and TEM) and by Fourier-transform infrared spectroscopy (FTIR), respectively. The catalytic performance of the prepared PE-rGO/Ag0 was assessed during the hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride (NaBH4). Experimental results indicate that PE-rGO/Ag0 with a surface of 6 cm2 (3x2 cm) showed the highest catalytic activity with an apparent reaction rate constant (Kapp) of 0.65 min−1. In addition, PE-rGO/Ag0 activity resulted to be comparable and significantly higher than previously reported values of silver-based catalysts. Remarkable stability values were achieved during different operating cycles without significant degradation in the catalytic activity, suggesting that PE-rGO/Ag0 can be used as a strong candidate in long-lasting chemical catalytic processes. [ABSTRACT FROM AUTHOR]

[Display omitted] Bacterial infection of biomedical implants is an important clinical challenge, driving the development of novel antimicrobial materials. The antibacterial effect of vertically aligned graphene as a nanoarray coating has been reported. In this study, vertically aligned graphene nanosheets decorated with silver nanoparticles were fabricated to enhance antibacterial effectiveness. Vertical graphene (VG) nanoflakes were synthesized by plasma-enhanced chemical vapor deposition (PECVD). Ag nanoparticles were attached to the surface of VG through using polydopamine and achieving a sustained release of Ag+. VG loaded with Ag nanoparticles (VGP/Ag) not only prevented bacterial adhesion for a long time, but also exhibited good biocompatibility. This work provides a new venue for designing antibacterial surfaces based on combination of graphene nanoarrays with other nanomaterials, and the results indicate that this approach could be very successful in preventing implant associated infections. [ABSTRACT FROM AUTHOR]

Bark cloth is a naturally nonwoven fabric from the Ficus natalensis tree. With its unique sustainable origins yet a few state-of-the-art utilizations, this study explored bark cloth's potential as an eco-friendly natural raw material to be embraced as a functional textile and furnishing. To enhance its salient features, it was green-loaded with a minimal amount of silver nanoparticles aided by the fabric constituent phytochemicals as reducing agents. The fabrics revealed promising antimicrobial properties. Silver nanoparticle (AgNP)–loaded fabrics had a 17-mm inhibition zone for Staphylococcus aureus bacteria, Candida albicans yeast, and Aspergillus niger fungus while 15 mm for Escherichia coli bacteria. Further bactericidal activity tests presented up to 100% reduction for Staphylococcus aureus and Escherichia coli. The modified and untreated bark cloth's morphology, color, chemical composition, thermal, and mechanical properties were also examined. Deposited AgNPs appeared spherical, while the unmodified fabric's terracotta color turned to dark brown. AgNP deposition was further confirmed by Fourier transform infrared spectroscopy, energy-dispersive, and X-ray diffraction analyses. AgNP-loaded fabrics were thermally stable up to 247 °C. Untreated bark cloth exhibited a tensile strength of 5.44 MPa along the tree circumference testing specimen cutting direction. Overall, the study's results present a unique sustainable fabric modification that could be used to valorize the renewable bark cloth into antimicrobial automotive interior liners and fashion garments. [ABSTRACT FROM AUTHOR]

Nanoparticles (NPs) are the subject of significant attention because of their unique physicochemical properties. Current antibiotic resistance status and microbial toxicity are the significant factors posing hurdles in disease management regularly. This research aimed to discover the antibacterial properties of silver nanoparticles (AgNPs) utilizing various species of gram-negative bacteria. Herein, the primary objective was to synthesize silver nanoparticles with a bio-reduction method using leaves extract of fenugreek. The silver nitrate and fenugreek leaves extract were used as precursor and reducing agents, respectively. Advanced analytical methods such as ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to characterize freshly produced AgNPs. UV-vis spectroscopy indicated a surface plasmon resonance (SPR) peak (maximum) at 415 nm, and SEM tests verified that the AgNPs were spherical with sizes varying from 20 to 50 nm. The planes (111), (200), (220), and (311) and 2θ values of 38.5°, 43.8°, 64.7°, and 77.5° were disclosed by the XRD patterns. The AgNPs were verified using the face-centered cubic (FCC), and they were shown to have antibacterial action toward Escherichia coli and Pseudomonas aeruginosa. The agar well diffusion (AWD) method was used with three concentrations (25 μg ml−1, 50 μg ml−1, and 100 μg ml−1), with zones of inhibition against P. aeruginosa and E. coli of 16.8 mm, 15.2 mm, and 12.8 mm, and 16 mm, 14.4 mm, and 12.8 mm, respectively. This significant (p < 0.05) antimicrobial activity may lead to the use of these NPs as nanomedicines against several diseases caused by gram-negative bacteria. [ABSTRACT FROM AUTHOR]

The Phlomis bracteosa Royle ex Benth. is one of the medicinal plants used by the people of the north-western Himalayan region, India. Initially, phytochemical components of this plants have been evaluated by estimating total phenolic, flavonoid and tannin contents, and also by GCMS analysis in acetone and methanol solvents, which listed twenty-four compounds in acetone and twenty-two in methanol extract with different percentage peak areas. Later, silver nanoparticles (SNPs) were biogenically synthesized from the acetone extract of the same plant. The formation of SNPs was observed with UV-vis spectroscopy with surface plasmon resonance (SPR) at 438 nm. Further, the Fourier transform infrared spectroscopy suggested the presence of carbonyls, nitrogenous compounds and different types of hydrocarbons in SNPs. The field emission scanning electron microscopy (FESEM) and the high-resolution transmission electron microscopy suggested the spherical shape of SNPs with average size of 43.53 ± 0.71 nm. On the other hand, the energy dispersive X-ray spectroscopy depicted Ag as major element, the selected area electron diffraction and the X-ray diffraction supported crystalline nature of synthesized SNPs. The antimicrobial and antioxidant activities of both extracts (acetone and methanol) and SNPs were also studied. For the antimicrobial activity analysis, disk diffusion and broth microdilution methods were selected which displayed that plant extracts (PEs) exhibited better activity against Gram-positive bacteria and were inactive against Escherichia coli, while synthesized SNPs displayed better antimicrobial activity against all selected microorganisms. In case of antioxidant activity, by following two methods i.e., DPPH radicle scavenging and reducing power methods again SNPs expressed better antioxidant property with lower IC50 value (40.55 µg/mL) than PEs i.e., 93.48 µg/mL (acetone) and 92.57 µg/mL (methanol). Therefore, biosynthetic SNPs can be a useful strategy in the biomedical sector. [ABSTRACT FROM AUTHOR]

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We report the synthesis of silver nanoparticles (Ag NPs) functionalized with L‐cysteine (Ag‐cys NPs) for colorimetric detection of contaminants: Hg2+, Pb2+, Cr6+ (CrO42−/Cr2O72), and As3+ in water samples. AgNPs synthesized were obtained in water from the mixture of the cationic and non‐ionic surfactants, cetyltrimethylammonium bromide (CTAB) and nonylphenol ethoxylate (NP‐10), respectively. Physicochemical characterization demonstrated a monomodal distribution of spherical nanoparticles with an average size of 8.25 nm. The stability of the Ag‐cys NPs was evaluated by determining the surface charge, which was found to be +27.95 mV, indicating the stability of Ag‐cys NPs against flocculation. The interaction between Ag‐cys NPs and solutions of contaminants was studied. This was done by measuring the shift in LSPR band of Ag NPs covered with cys in the region of 400–450 nm. We observed a change or disappearance of color visually, indicating aggregation or oxidation of the Ag NPs. Concentration of cys, as well as the pH of the nanoparticles, were crucial in studying the aggregation process. This is a preliminary study in search of benefits such as low cost, in situ usability, ease of use, and rapid response making it a potential alternative to traditionally employed spectroscopic methods. [ABSTRACT FROM AUTHOR]

Biosurfactants prevent agglomeration of nanoparticles by reducing the surface tension and offer stability over time by forming a stable layer on the surface of nanoparticles. The current study focuses on the biosynthesis of silver nanoparticles (SNP) coated with a rhamnolipid biosurfactant (BS) and its use as an additive in fabric cleaning detergent. Rhamnolipids were extracted from a Pseudomonas aeruginosa strain, Pa84, that was isolated from a halophilic environment, Sambhar Salt Lake, Rajasthan, India. The reduction of silver ions was achieved by the rhamnolipid‐coated SNP (BS‐SNP). BS, SNP, and BS‐SNP demonstrated antibacterial efficacy against a variety of microorganisms. Lipase, present in the crude biosurfactant, was immobilized on modified chitosan microbeads (Ch‐BS‐SNP) and used for washing fabrics. The conjugate was found to be effective as a laundry detergent additive. The immobilized lipase showed high relative activity ranging from 66% to 110% and performed better than free lipase or standards. Our results highlight a potential claim for a commercially viable laundry detergent additive. [ABSTRACT FROM AUTHOR]

Surfaces composed of self-assembled metal nanoparticles, prepared by physical vapor deposition, can generate lithography-free, pristine and easily scalable substrates for surface-enhanced Raman scattering (SERS). These substrates exhibit remarkable SERS enhancement factor (EF) spanning several orders of magnitude. In this study, we present a facile method to achieve further amplification of these EF values through formation of a Fabry–Perot cavity, which effectively enhances the field around the nanoparticles through constructive interference. We have observed that this enhancement by a quarter-wave Fabry–Perot cavity is superior to a near-field enhancement by a plasmonically coupled metallic mirror within a few nm proximities of a metal nanoparticle layer. Using Ag nanoparticles on a 90 nm thick SiO2 spacer with a metallic mirror, a SERS EF of 1.3 × 1010 with a detection limit down to 10–13 M was observed. Furthermore, we have observed even a simpler far-field cavity supporting only specular reflections can yield a 5-fold gain compared to a standalone nanoparticle-on-glass SERS substrate. Based on this observation we have designed a low-cost, reusable mirror platform that can be dry stamped on an Ag nanoparticle coated glass coverslip, yielding a SERS EF of 5.3 × 109 with a detection limit down to 10–12 M. Such a stamped mirror platform serves a dual purpose. It acts as an external element to enhance the capabilities of any SERS substrate with a flat surface, and also as a long-term protective barrier against airborne contaminants that can degrade the Raman signal quality. [ABSTRACT FROM AUTHOR]

Smart innovative nanocomposites based on active ingredients and metallic nanoparticles with effective wound healing and antifungal properties are efficient in overcoming the limitations of traditional therapeutic products. Open wounds provide an ideal niche for colonization by Candida albicans (C. albicans) which poses substantial global health issues owing to delayed wound healing and disordered healing mechanisms. Therefore, proficient innovative therapies that control C. albicans infection and promote wound healing are of imperative importance for the management of wounds and prevention of infection and possible complications. This study aims to design a novel nanocarrier platform based on a hydrogel loaded with silver nanoparticles (AgNPs) and doped with pomegranate peel extract (PPE) and hyaluronic acid (HA), offering an unprecedented opportunity to achieve skin repair and manage C. albicans colonization with an efficient wound healing process. Sprague-Dawley rats (n=100) were assigned to 5 groups and infected with C. albicans and distributed as follows: control positive (untreated) and four cutaneous wound-healing model groups treated topically with commercial cream and PPE-HA-AgNPs at full, 50%, and 25% concentrations for 15 days, respectively. Our findings revealed that the severity of clinical signs, C. albicans burden, and the expression of biofilm-related genes ALS1 , HYR1 , and PLB1 were diminished following treatment with PPE-HA-AgNPsIII. Notably, the formulated nanocomposite was very effective in extending the release of PPE-HA-AgNPs in infected wounds with retention percentages of 65.4% for PPE-HA-AgNPsIII. Topical administration of PPE-HA-AgNPsIII successfully alleviated the extensive inflammatory response and healed wounded skin via downregulation of tumor necrosis factor-alpha (TNF-α), interleukin-6 and IL-1 beta, and nitric oxide synthase (NOS) levels as shown by enzyme-linked immunosorbent (ELISA) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays. Interestingly, PPE-HA-AgNPsIII modulated angiogenic and wound healing markers as evidenced by the downregulation of MMP-9 and the upregulation of angiopoietin-1 (Ang-1), vascular endothelial growth factor (VEGF) (up to 10 days post-treatment), transforming growth factor-beta 1 (TGF-β1), bFGF , EGF, Ki- 67, and collagen I and III with efficient wound closure capability. This was evidenced by the lessening of histopathological severity, which accelerated the healing of the infected skin wounds post-treatment with PPE-HA-AgNPs. Overall, our formulated PPE-HA-AgNPs provide an effective innovative therapeutic strategy for the treatment of cutaneous wounds infected with C. albicans with maximized wound healing efficacy, indicating their potential in clinical practice. [ABSTRACT FROM AUTHOR]

Background: Acinetobacter baumannii is a critical pathogen associated with hospital-acquired infections, particularly in burn and intensive care unit (ICU) patients, and is notorious for its high level of antibiotic resistance. This study aims to evaluate the antibacterial potential of silver nanoparticles (AgNPs) synthesized using Acroptilon repens extract as a promising alternative treatment for combating multidrug-resistant A. baumannii. Methods and results: Twelve clinical isolates of A. baumannii were identified through biochemical testing. Antibiotic susceptibility testing using the Kirby–Bauer disk diffusion method revealed universal resistance to ceftazidime, amikacin, imipenem, gentamicin, ciprofloxacin, and piperacillin-tazobactam, while all isolates remained sensitive to colistin (p ≤ 0.05). AgNPs were synthesized using A. repens extract and characterized through transmission electron microscopy (TEM), scanning electron microscopy (SEM), particle size analysis (PSA), UV-Vis spectroscopy, X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). TEM analysis showed that the AgNPs had a spherical morphology with an average particle size of approximately 30 nm, while SEM confirmed their spherical shape and size distribution, ranging from 10 to 130 nm, with a mean size of 38.89 nm. UV-Vis spectroscopy confirmed the successful formation of AgNPs, indicated by a distinct broad absorption peak between 400 and 480 nm. XRD analysis validated the crystalline nature of the nanoparticles, with characteristic peaks at 2θ values of 38.21°, 46.28°, 64.57°, and 77.49°, corresponding to the (111), (200), (220), and (311) planes of face-centered cubic (fcc) silver. Antibacterial activity was evaluated by determining the minimum inhibitory concentration (MIC), which ranged from 50 to 400 µg/mL. The highest inhibitory activity was observed at 400 µg/mL. Gene expression analysis using quantitative real-time PCR (qRT-PCR) demonstrated downregulation of the oprD and carO porin genes following AgNP treatment. However, these reductions were not statistically significant (p = 0.302 and p = 0.198, respectively). Conclusions: AgNPs synthesized from A. repens demonstrated strong antibacterial activity against multidrug-resistant A. baumannii. While downregulation of porin genes was observed, further investigation is required to elucidate the underlying mechanisms of action and assess their potential clinical applications. These findings support the potential of AgNPs as an alternative therapeutic strategy for addressing A. baumannii infections resistant to conventional antibiotics. [ABSTRACT FROM AUTHOR]

Introduction: In the global field of nanotechnology, the production of silver nanoparticles (AgNPs) is an environmentally beneficial technique. To prevent the diseases caused by many commonly used pesticides, it is essential to synthesize safe alternatives from low-cost sources. Material and methods: This study focuses on the eco-friendly extracellular production of AgNPs using an aqueous extract of Ulva lactuca as a reducing agent in a silver nitrate solution. The biosynthetic reaction was confirmed through various analytical techniques, including ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and energy dispersive X-ray analysis (EDAX). Moreover, antioxidant activity was confirmed. It has also been evaluated against a variety of bacteria and fungi that have an impact on humans, animals, and plants. Results and discussion: The mean size of the nanoparticles (NPs) varied from 45–61 nm. The disk diffusion testing results show that, in comparison to the tested antibiotics, Staphylococcus aureus , Escherichia coli , Staphylococcus epidermidis , and Klebsiella pneumoniae were more responsive to U. lactuca -silver nanoparticles (U-AgNPs) extract. eldor 50% sc fungicide was used at the prescribed dose of 0.5 μL/mL, and the antifungal activity of aqueous and U-AgNPs extracts was examined at three concentrations of 0.62, 1.25, and 2.5 mg/mL. Through the suppression of spore germination, in vitro investigations demonstrated that U-AgNPs at varying doses greatly hindered the process of reproductive growth of Botrytis cinerea. Comparing U-AgNPs to the standard synthetic fungicide Teldor 50% sc, it is noteworthy to observe that a substantial control efficacy against tomato and strawberry gray mold was noticed, especially at concentrations of 2.5mg/mL on the entire tomato and strawberry plants and also on the detached leaves and fruits without causing any appearance damage. In summary, this study advances the field of agronanotechnology by demonstrating the potential application of a fungicide based on NPs to prevent gray mold on tomato and strawberry plants in greenhouse environments and throughout the postharvest phase. [ABSTRACT FROM AUTHOR]

Preparing bismuth compounds-based heterojunctions with superior redox capability has emerged as a promising strategy for environmental remediation. Herein, p-BiOI/n-Bi 2 WO 6 heterojunctions were successfully obtained via a novel, facile, and green solvothermal method. The heterojunctions were synthesized using different mass ratios (1:2, 1:1, and 2:1) of BiOI (BI) and Bi 2 WO 6 (BW), with 1:1 as the best ratio, which was decorated with silver nanoparticles (Ag-NPs) and nitrogen-doped graphene (NG) applying green methodologies. The as-prepared BI/BW heterojunctions were characterized by several techniques, and their adsorption capacity and photodegradation activity toward tetracycline (TC) under 19 W visible LEDs illumination were investigated. The capacity of pure BI, BW and BI/BW heterojunctions for adsorbing TC ranged from 14 to 68 mg/g; among the heterojunctions, Ag/1BI/1BW showed the highest TC adsorption capacity, 35 mg/g. Moreover, the photocatalytic tests revealed that the Ag/1BI/1BW exhibited the highest catalytic performance, achieving a TC percentage degradation of 81 % within 120 min. The low nominal power consumption of the LED-based photoreactor (0.0475 kWh) was significantly lower than that reported in the literature for using Xe or Hg lamps. In addition, catalyst dosage, initial TC concentration, and solution pH were investigated, demonstrating that they play important role in TC photodegradation. Scavenger assays determined that the degradation of TC using Ag/1BI/1BW proceeds mainly via superoxide radicals and holes, which agrees with the carrier transfer mechanism postulated for this heterojunction. TOC analysis revealed that the efficiency of Ag/1BI/1BW was 63 %, and reuse tests confirmed its high performance even after three cycles. This research provides new insights into the design of high-performance heterojunctions for water treatment. [ABSTRACT FROM AUTHOR]

Microneedles are mainly used for pain-free drug administration and in biosensing for wearable systems. They are also promising for fields such as agronomy for precision farming, but their fabrication is not straightforward, often requiring expensive equipment and cleanroom protocols, being unsuitable for mass production. Here, we report a new and simple method for the scalable fabrication of all-inkjet-printed conductive microneedles based on silver nanoparticles (extensible to any other metallic nanoparticle ink) and a simple example of their application for monitoring the electrochemical properties of plants. [ABSTRACT FROM AUTHOR]

Currently, Nano-materials have been explored for their abundant biomedical applications. In the present study the green synthesized (SC-AgNPs) by root extract of Smilax Chenensis have been characterized by UV–visible spectroscopy revealed SPR peak at 432 nm and FT-IR data reveals that the bioactive components of root extract have been actively involved in the reduction and stabilization of SC-AgNPs. TEM and AFM results revealed that SC-AgNPs were roughly spherical in shape. Further, the particle size of SC-AgNPs was also carried out by Dynamic Light Scattering method by aqueous colloidal solution and the results reveals that the SC-AgNPs are poly-dispersed in nature with an average size 45.6 nm with a Z average of 39.5 nm. The stability of colloidal SC-AgNPs was further confirmed by negative zeta potential value of − 21.0 mV. The SC-AgNPs showed good antibacterial activity against both gram –ve and gram + ve bacteria, whereas, SC-AgNPs coupled with antibiotic reveals excellent and enhanced antibacterial activity. The gram –ve E.coli and gram + ve S.aureus revealed highest zone of inhibition when compared to other two bacterial species. So, SC-AgNPs coupled with antibiotics can be excellent alternative to treat antibiotic resistant bacteria. The SC-AgNPs also reveals excellent antioxidant activity among them DPPH method revealed superior activity with an IC50 value76.22. The SC-AgNPs also reveals superior anticancer activity against MDA-MB-231 with IC50 value of 33.98 µg/mL and photo-catalytic activity the optical density of reduced from 1.861 to 0.135 OD within 30 min. The green SC-AgNPs detected to have multiple therapeutic applications. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) were synthesized in an aqueous solution via the reduction of AgNO3 employing citrate reducing agent. The resultant AgNPs were first assayed for the catalytic H2 evolution in an acidic electrolyte, namely pH 0.3 H2SO4 solution, showing negligible activity. The AgNPs were then conditioned in the same electrolyte solution while repeating the cyclic potential polarization between −0.25 V and 0.95 V (or 1.8 V) versus RHE. Effects of the electrochemical treatment to the morphology, crystalline, surface chemistry and H2 evolution catalytic activity of AgNPs were examined. It was found that the electrochemical treatment remarkably boosted the H2 evolution catalytic activity of AgNPs. The electrochemically activated AgNPs represents an attractive Pt‐free catalyst for the H2 evolution in acidic medium. [ABSTRACT FROM AUTHOR]

Reverse osmosis (RO) is the most common method for treating salt and brackish water. As a membrane‐driven process, a key challenge for RO systems is their susceptibility to scaling and biofouling. To address these issues, functional coatings utilizing metal nanoparticles (MNPs) are developed. In this study, silver, gold, and copper nanoparticles are applied onto thin‐film composite (TFC) membranes using plasma‐enhanced magnetron sputtering. The elemental composition, surface morphology, and hydrophilicity of the coatings are analyzed using X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and contact angle measurements. The antimicrobial properties and the filtration efficiency of the coated membranes are assessed through application‐specific experimental setups. Silver and copper nanoparticles exhibit superior antimicrobial properties, reducing microorganism adhesion by a factor of 103 compared to uncoated membranes. Under appropriate coating conditions, no deterioration in filtration performance is observed. Enhancing the adhesion of MNPs is necessary for achieving sustained release of metal ions. [ABSTRACT FROM AUTHOR]