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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]

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]

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]

Carica papaya seeds were used in this research for the synthesis of AgNPs. The production of silver nanoparticles was characterized using UV–Vis spectroscopy, FTIR, XRD and SEM-EDX analysis. The antibacterial activity of the prepared AgNPs was evaluated by the Kirby–Bauer disc diffusion method with the antibacterial activity of different compounds against Bacillus aerogenes. UV–Vis spectral peaks are found at 8–18 nm. SEM and TEM analysis revealed several spherical structures between 10 nm and 50 nm. XRD analysis also confirmed its 50 nm size. Experimental data revealed that AgNPs inhibited bacterial growth. This study shows that papaya seed extract contributes to the bioreduction and stabilization of the synthesized silver nanoparticles. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa) stands as a crucial staple food worldwide, especially in Bangladesh, where it ranks as the third-largest producer. However, intensified cultivation has made high-yielding rice varieties susceptible to various biotic stresses, notably sheath blight caused by Rhizoctonia solani, which inflicts significant yield losses annually. Traditional fungicides, though effective, pose environmental and health risks. To address this, nanotechnology emerges as a promising avenue, leveraging the antimicrobial properties of nanoparticles like silver nanoparticles (AgNPs). This study explored the green synthesis of AgNPs using Ipomoea carnea leaf extract and silver nitrate (AgNO3), and also examined their efficacy against sheath blight disease in rice. The biosynthesized AgNPs were characterized through various analytical techniques such as UV-vis spectrophotometer, X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Particle size analyzer, Zeta potential, Scanning Electron Microscope (SEM), Field Emission Scanning Electron Microscope (FESEM), Transmission Electron Microscope (TEM) for confirming their successful production and crystalline nature of nanoparticles. The results of UV-visible spectrophotometers revealed an absorption peak ranging from 421 to 434 nm, validated the synthesis of AgNPs in the solution. XRD, DLS, and TEM estimated AgNPs sizes were ~45 nm, 66.2nm, and 46.38 to 73.81 nm, respectively. SEM and FESEM demonstrated that the synthesized AgNPs were spherical in shape. In vitro assays demonstrated the significant inhibitory effects of AgNPs on mycelial growth of Rhizoctonia solani, particularly at higher concentrations and pH levels. Further greenhouse and field experiments validated the antifungal efficacy of AgNPs against sheath blight disease in rice, exhibiting comparable effectiveness to commercial fungicides. The findings highlight the potential of AgNPs as a sustainable and effective alternative for managing rice sheath blight disease, offering a safer solution amidst environmental concerns associated with conventional fungicides. [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]

The present study focused on evaluating the antibacterial properties, radical scavenging, and photocatalytic activities of Centaurea behen-mediated silver nanoparticles (Cb-AgNPs). The formation of Cb-AgNPs was approved by UV–Vis spectrometry, Fourier-transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction. The results showed that the obtained AgNPs have a maximum absorbance peak at 450 nm with spherical morphology and an average size of 13.03 ± 5.8 nm. The catalytic activity of the Cb-AgNPs was investigated using Safranin O (SO) solution as a cationic dye model. The Cb-AgNPs performed well in the removal of SO. The coupled physical adsorption/photocatalysis reaction calculated about 68% and 98% degradation of SO dye under solar irradiation. The Cb-AgNPs inhibited the growth of gram-negative or positive bacteria strains and had excellent DPPH radicals scavenging ability (100% in a concentration of 200 µg/ml) as well as a good effect on reducing coagulation time (at concentrations of 200 and 500 µg/mL reduced clotting time up to 3 min). Considering the fact that green synthesized Cb-AgNPs have antioxidant and antibacterial properties and have a good ability to reduce coagulation time, they can be used in wound dressings. As well as these NPs with good photocatalytic activity can be a suitable option for degrading organic pollutants. [ABSTRACT FROM AUTHOR]

This study aimed to develop a novel Gelatin silver oxide material for releasing nitric oxide bionanocomposite wound dressing with enhanced mechanical, chemical, and antibacterial properties for the treatment of diabetic wounds. The gelatin- silver oxide nanoparticles (Ag2O-NP) bio nanocomposite was prepared using chitosan and gelatin polymers incorporated with silver oxide nanoparticles through the freeze-drying method. The samples were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Results showed that the Ag2O-NP nanoparticles increased porosity, decreased pore size, and improved elastic modulus. The Ag2O-NP wound dressing exhibited the most effective antibacterial properties against Staphylococcus aureus and Escherichia coli. Among the samples, the wound dressing containing silver oxide nanoparticles demonstrated superior physical and mechanical properties, with 48% porosity, a tensile strength of 3.2 MPa, and an elastic modulus of 51.7 MPa. The fabricated wound dressings had a volume ratio of empty space to total volume ranging from 40% to 60%. In parallel, considering the complications of diabetes and its impact on the vascular system, another aspect of the research focused on developing a per2mediated wound dressing capable of releasing nitric oxide gas to regenerate damaged vessels and accelerate diabetic wound healing. Chitosan, a biocompatible and biodegradable polymer, was selected as the substrate for the wound dressing, and beta-glycerophosphate (GPβ), tripolyphosphate (TPP), and per2mediated alginate (AL) were used as crosslinkers. The chitosan-alginate (CS-AL) wound dressing exhibited optimal characteristics in terms of hole count and uniformity in the scanning electron microscope test. It also demonstrated superior water absorption (3854%) and minimal air permeability. Furthermore, the CS-AL sample exhibited an 80% degradation rate after 14 days, indicating its suitability as a wound dressing. The wound dressing was loaded with S-nitrosoglutathione (GSNO) powder, and the successful release of nitric oxide gas was confirmed through the grease test, showing a peak at a wavelength of 540 nm. Subsequent investigations revealed that the treatment of human umbilical vein endothelial cells (HUVECs) with high glucose led to a decrease in the expression of PER2 and SIRT1, while the expression of PER2 increased, which may subsequently enhance the expression of SIRT1 and promote cell proliferation activity. However, upon treatment of the cells with the modified materials, an increase in the expression of PER2 and SIRT1 was observed, resulting in a partial restoration of cell proliferative activity. This comprehensive study successfully developed per2-mediated bio-nanocomposite wound dressings with improved physical, mechanical, chemical, and antibacterial properties. The incorporation of silver oxide nanoparticles enhanced the antimicrobial activity, while the released nitric oxide gas from the dressing demonstrated the ability to mitigate vascular endothelial cell damage induced by high glucose levels. These advancements show promising potential for facilitating the healing process of diabetic wounds by addressing complications associated with diabetes and enhancing overall wound healing. [ABSTRACT FROM AUTHOR]

In this study, we report the synthesis of silver nanoparticles (AgNP’s) by reducing silver ions from a solution of silver nitrate with an aqueous extract from Azadirachta indica. Using silver ions as the catalyst, nanoparticles were formed in 8min without the use of toxic chemicals. As evidenced by UV-vis spectroscopy, a broad surface plasmon resonance spectrum at 225nm was detected, which indicates the colloidal solution of silver nanoparticles is stable and produces silver nanoparticles. As revealed by the fourier transform-infrared spectrometer (FTIR) analysis, the flower extract contained a variety of biomolecules that acted as capping and reducing agents for the synthesis of AgNPs. As determined by X-ray diffraction (XRD), silver nanoparticles displayed a crystalline structure and ranged in size from 18 to 39nm. In addition to these findings, transmission electron microscopy (TEM) images showed that the silver nanoparticles were spherical and rod-shaped, as confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX). A variety of pathogenic bacteria, such as Klebsiella pneumoniae, Escherichia coli, Bacillus subtilis and Staphylococcus aureus, were tested against AgNP’s antibacterial properties. A significant inhibition zone was observed for Escherichia coli when AgNPs were applied at different concentrations. Silver nanoparticles were shown to have antidiabetic effects through a diphtheria assay with inhibition rates ranging from 31.09% to 83.33% for concentrations of 50–250μg/mL. As researchers seek natural sources of compounds with potential health benefits, silver nanoparticles were also investigated for their antioxidant properties. [ABSTRACT FROM AUTHOR]

Electrospinning has garnered much attention for skin renewal, emphasizing skin's pivotal role as a primary protective layer and the susceptibility to loss caused by burns. The research aimed to develop a multipurpose wound dressing that safeguard injuries and facilitates the renewal of dermal tissues. Two-layer nanofibers were prepared using polyvinyl alcohol–chitosan–gelatin/polyacrylonitrile (PVA–CS–Gel/PAN), containing mupirocin (Mu 3% w/w) in underlying layer and silver nanoparticles (AgNps) in the upper layer with varying concentrations. AgNps were synthesized from Capsella bursa-pastoris extract by the green method and characterized using XRD, SEM, FTIR, and UV techniques. Then, PVA–CS–Gel/PAN solutions with AgNps and Mu were electrospun into multilayer dressings. The effectiveness of the nanofibers was evaluated through in vitro and in vivo tests. The study examined the nanofibers containing spherical AgNps with an average diameter of 72.57 nm and a negative surface charge (− 12 mv). They had uniform and smooth surfaces with a diameter range of 476.31 to 926.04 nm. According to swelling and contact angle results, hydrophilicity of samples had a direct relation with water absorption. Controlled drug release within 72 h followed Higuchi or first-order profiles. MTT and antibacterial analyses indicated that optimized nanofibers (Mu/1% AgNps) had suitable biocompatibility and synergistic potential against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. Additionally, an in vivo test on rats with second-degree burns after 28 days demonstrated a 98.97% improvement in revival, outperforming its commercial counterparts. Consequently, the results position the designed composite nanofiber as a promising candidate for wound healing applications, aiding in enhancing skin regeneration. [ABSTRACT FROM AUTHOR]

Herein, single step biosynthesis of silver nanoparticles (AgNPs) is reported by using AgNO3 and Monstera deliciosa (MD) leaf extract. Spherical AgNPs are obtained with difference in particle sizes and antibacterial activities using two sets of MD leaf extract having different heating periods 5 and 10 min. They are characterized by UV–vis spectroscopy, X‐ray diffraction (XRD), Zeta potential, Attenuated Total Reflectance Infrared Spectroscopy (ATR‐IR), and Field Emission Scanning Electron Microscopy (FE‐SEM). Dynamic Light Scattering (DLS) studies propose two types of AgNPs have hydrodynamic diameters of 104 and 80 nm. Nuclear Magnetic Resonance (NMR), Gas Chromatography‐Mass Spectrometry (GC‐MS), and High Resolution−Mass Spectrometry (HR‐MS) studies, which reveal the presence of various phytochemicals found in MD leaf extract. These biomolecules play a vital role as stabilizing and reducing agents to fabricate stable AgNPs. These AgNPs exhibit strong antibacterial activities having effective zone of inhibition for both Gram‐positive (Staphylococcus aureus, Bacillus subtilis) and Gram‐negative (Escherichia coli, Pseudomonas aeruginosa) microorganisms, nonetheless AgNPs against different fungi (Penicillium sp., Aspergillus flavus, Fusarium oxysporum, Rhizoctonia solani) show non‐antifungal characteristics because of their inert nature. This study suggests that AgNPs can be used in treating bacterial infections and drug delivery also for several therapeutic and diagnostic applications. [ABSTRACT FROM AUTHOR]

AbstractThis study explores the corrosion resistance and antibacterial properties of a PTFE + TiO2/Ag coating applied to 316 L stainless steel. To enhance adhesion, a polydopamine interlayer was chemically deposited onto the steel surface. The PTFE + TiO2 coating was subsequently applied through immersion, followed by the deposition of silver nanoparticles using a chemical method. Optimization of the polydopamine interlayer involved varying temperature, time, stirring speed, and drying parameters. The optimal conditions for the polydopamine interlayer were determined to be 60 °C for 1 h, 300 rpm stirring, and 24-h drying in a freeze dryer. Analytical results demonstrated that both the PTFE + TiO2 and PTFE/PTFE + TiO2/Ag coatings exhibited exceptional corrosion resistance, with corrosion currents of 3.3 × 10−5 and 3.2 × 10−4 μA/cm2, respectively. Antibacterial assessments showcased the remarkable ability of the PTFE/PTFE + TiO2/Ag coating, containing 5% silver content, to effectively inhibit bacterial penetration within a 6.5 mm radius. Furthermore, this coating displayed a water contact angle of 143°, classifying it as a hydrophobic coating. The photocatalytic efficiency (Rs) was determined to be 3.18 × 10−3 A/W, a performance level comparable to that of a standard UV sensor. These findings underscore the substantial enhancements in corrosion resistance, antibacterial performance, and hydrophobic characteristics achieved with the PTFE + TiO2/Ag coating, particularly through the novel optimization of the polydopamine interlayer. This coating exhibits great promise for multifunctional protective applications in diverse fields, particularly demonstrating its suitability for implants and bio-coatings. [ABSTRACT FROM AUTHOR]

Background: The non-toxic self-crosslinked hydrogel films designed from biocompatible materials allow for controlled drug release and have gathered remarkable attention from healthcare professionals as wound dressing materials. Thus, in the current study the chitosan (CS) film is infused with oil-in-water Pickering emulsion (PE) loaded with bioactive compound quercetin (Qu) and stabilized by dialdehyde cellulose nanocrystal-silver nanoparticles (DCNC-AgNPs). The DCNC-AgNPs play a dual role in stabilizing PE and are involved in the self-crosslinking with CS films. Also, this film could combine the advantage of the controlled release and synergistic wound-healing effect of Qu and AgNPs. Results: The DCNC-AgNPs were synthesized using sodium periodate oxidation of CNC. The DCNC-AgNPs were used to stabilize oil-in-water PE loaded with Qu in its oil phase by high speed homogenization. Stable PEs were prepared by 20% v/v oil: water ratio with maximum encapsulation of Qu in the oil phase. The Qu-loaded PE was then added to CS solution (50% v/v) to prepare self-crosslinked films (CS-PE-Qu). After grafting CS films with PE, the surface and cross-sectional SEM images show an inter-penetrated network within the matrix between DCNC and CS due to the formation of a Schiff base bond between the reactive aldehyde groups of DCNC-AgNPs and amino groups of CS. Further, the addition of glycerol influenced the extensibility, swelling ratio, and drug release of the films. The fabricated CS-PE-Qu films were analyzed for their wound healing and tissue regeneration potential using cell scratch assay and full-thickness excisional skin wound model in mice. The as-fabricated CS-PE-Qu films showed great biocompatibility, increased HaCat cell migration, and promoted collagen synthesis in HDFa cells. In addition, the CS-PE-Qu films exhibited non-hemolysis and improved wound closure rate in mice compared to CS, CS-Qu, and CS-blank PE. The H&E staining of the wounded skin tissue indicated the wounded tissue regeneration in CS-PE-Qu films treated mice. Conclusion: Results obtained here confirm the wound healing benefits of CS-PE-Qu films and project them as promising biocompatible material and well suited for full-thickness wound healing in clinical applications. [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 short alkyl chain of N‐octylamine was demonstrated to be able to transfer silver nanoparticles (AgNPs) from the aqueous to toluene phase with a narrow average size lower than 10 nm via ligand exchange between N‐octylamine and the sodium citrate used as a reducing and stabilizing agent during AgNPs synthesis. Surface plasmon analysis by UV‐visible spectroscopy showed that the N‐octylamine concentration significantly influences the concentration and stability of AgNPs transferred to the toluene phase and the time required for such transfer. Then, the transferred silver nanoparticles were deposited on a polydimethylsiloxane (PDMS) substrate by drop‐casting (PDMS‐T‐50‐D) or immersion (PDMS‐T‐50‐I). XPS analysis demonstrated that the AgNPs are deposited at lower than 0.02 % atomic percentages through both deposition methods. The Raman signal and the noise by fluorescence signal were shown to be significantly influenced by the AgNPs deposition method on PDMS film. The trace content of AgNPs on the flexible PDMS films on both PDMS‐T‐50‐D and PDMS‐T‐50‐I substrates can eliminate the fluorescence signal of the analyte; however, only the PDMS‐T‐50‐I substrate demonstrated a remarkable SERS‐enhanced signal. These results could significantly contribute to the design of new flexible and removable SERS substrates with ultra‐low contents of noble metal NPs. [ABSTRACT FROM AUTHOR]

In this study, we present a one‐pot synthetic approach for the preparation of metal oxide nanocomposites. Our investigation combines various analytical techniques, including FTIR, XRD, UV‐vis DRS, PL, XPS, SEM, EDX, and XANES, to comprehensively identify heterogeneous structures: SnO2‐CuO, CuO‐SnO2, NiO‐TiO2, and TiO2‐NiO. These metal oxide‐linked semiconductor solids serve as catalysts for dye photodegradation and exhibit remarkable biological activity. Our research is centered on exploring the photocatalytic potential of SnO2‐CuO nanocomposites while emphasizing the optimization of their photocatalytic and biological activities. This optimization is achieved through the careful incorporation of an ideal quantity of SnO2, as confirmed by EDX data, which reveals the composition as follows: O: 78.58 weight percent (0.525 keV), Cu: 12.61 weight percent (0.954 keV), and Sn: 8.81 weight percent (0.400 keV). Notably, under direct sunlight irradiation, the degradation efficiency of Rhodamine B dye surpasses that of pristine CuO, SnO2, TiO2, and NiO nanoparticles. Additionally, we explore the antimicrobial properties of these prepared samples at varying concentrations (50, 100, and 150 μl) against the pathogenic bacterium Staphylococcus aureus. Our findings highlight their effectiveness as antimicrobial agents. This research offers a promising method for developing highly active metal‐oxide‐linked nanomaterials, suitable for efficiently removing organic dye contaminants from water systems and showing great potential in antimicrobial applications. [ABSTRACT FROM AUTHOR]

Super hydrophobic porous silicon surface is prepared using a wet chemical synthesis route. Scanning electron microscopic investigation confirms a correlation between pore size and reaction time. SERS substrates are prepared by silver nanoparticle deposition on porous silicon surface. They exhibit excellent characteristics in terms of sensitivity, reproducibility, stability, and uniformity. They could detect rhodamine 6G in femtomolar range with SERS enhancement factor of ~ 6.1 × 1012, which is best ever reported for these substrates. Molecule-specific sensing of water pollutants such as methylene blue, glyphosate, and chlorpyrifos, is demonstrated for concentrations well below their permissible limits along with excellent enhancement factors. Porous silicon substrate functionalized with Ag nanoparticles demonstrates to be a promising candidate for low-cost, long-life, reliable sensors for environmental conservation applications. [ABSTRACT FROM AUTHOR]

The adoption of green chemistry protocols in nanoparticle (NP) synthesis has exhibited substantial potential and is presently a central focus in research for generating versatile NPs applicable across a broad spectrum of applications. In this scientific contribution, we, for the first time, examined the ability of Aconitum Laeve (A. Laeve) crude extract to synthesize silver and gold nanoparticles (AgNPs@AL; AuNP@AL) and explored their potential applications in biological activities and the catalytic degradation of environmental pollutants. The synthesized NPs exhibited a distinctive surface plasmon resonance pattern, a spherical morphology with approximate sizes of 5–10 nm (TEM imaging), a crystalline architecture (XRD analysis), and potential functional groups identified by FTIR spectroscopy. The antibacterial activity was demonstrated by inhibition zones that measured 16 and 14 mm for the AgNPs@AL and AuNP@AL at a concentration of 80 µg/mL against Staphylococcus aureus and 14 and 12 mm against Escherichia coli, respectively. The antioxidant potential of the synthesized NPs was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-Oxide (PTIO), and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Our findings suggest that the AuNP@AL effectively countered the tested radicals considerably, displaying IC50 values of 115.9, 103.54, and 180.85 µg/mL against DPPH, PTIO, and ABTS, respectively. In contrast, the AgNPs@AL showed IC50 values of 144.9, 116.36, and 95.39 µg/mL against the respective radicals. In addition, both the NPs presented significant effectiveness in the photocatalytic degradation of methylene blue and rhodamine B. The overall observations indicate that A. Laeve possesses a robust capability to synthesize spherical nanoparticles, exhibiting excellent dispersion and showcasing potential applications in both biological activities and environmental remediation. [ABSTRACT FROM AUTHOR]

Pomegranate waste poses an environmental challenge in Arequipa. Simultaneously, interest in sustainable materials like natural rubber latex (NRL) is growing, with Peruvian communities offering a promising source. This study explores the green synthesis of silver nanoparticles (AgNPs) using pomegranate peel extract and their incorporation into NRL nanofibers for enhanced functionalities. An eco-friendly process utilized silver nitrate and pomegranate peel extract as a reducing and capping agent to synthesize AgNPs. The resulting AgNPs and NRL/AgNPs nanofibers were characterized using imaging and spectroscopic techniques such as UV-vis, TGA, FTIR, XRD, Raman, SEM, and DLS. Green-synthesized AgNPs were spherical and crystalline, with an average diameter of 59 nm. They showed activity against K. pneumoniae, E. coli, B. cereus, and S. aureus (IC50: 51.32, 4.87, 27.72, and 69.72 µg/mL, respectively). NRL and NRL/AgNPs nanofibers (300–373 nm diameter) were successfully fabricated. The composite nanofibers exhibited antibacterial activity against K. pneumoniae and B. cereus. This study presents a sustainable approach by utilizing pomegranate waste for AgNP synthesis and NRL sourced from Peruvian communities. Integrating AgNPs into NRL nanofibers produced composites with antimicrobial properties. This work has potential applications in smart textiles, biomedical textiles, and filtration materials where sustainability and antimicrobial functionality are crucial. [ABSTRACT FROM AUTHOR]

A comparative study was applied to investigate the potential of Callistemon citrinus (bottlebrush) flower extract (BBE) and Punica granatum (pomegranate) peel extracts (PPE) for the sustainable synthesis of the silver nanoparticles, Ag-BBE and Ag-PPE, respectively. The synthesis process of Ag NPs using the selected extracts was applied under optimized conditions. Hence, the effect of the selected plant's type on the different characteristics of the synthesized green Ag NPs was investigated. The UV-Vis spectroscopy revealed the presence of the characteristic silver peaks at 419 and 433 nm of the Ag-BBE and Ag-PPE, respectively. The XRD spectra reported the fcc phase formation of Ag NPs. The TEM results highlighted the morphological features of the synthesized Ag NPs. with a size range of 20–70 nm, and with 10–30 nm for Ag-BBE and Ag-PPE, correspondingly. The Raman spectra revealed characteristic silver bands in the Ag-PPE and reflected some bands related to the natural extract in the Ag-BBE sample. The antimicrobial activity and statistical analysis investigation were conducted against four selected oral pathogens (Staphylococcus aureus (SA), Candida albicans (CA), Staphylococcus epidermidis (S. epi), and Enterococcus faecalis (EF)). Both tested extracts, BBE, and PPE, revealed potential effectivity as reducing and capping agents for Ag NP green synthesis. However, the synthesized NPs demonstrated different features, depending on the used extract, reflecting the influence of the plant's biomolecules on the nanoparticles' properties. [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]

Silver nanoparticles (Ag NPs) have been produced by low-dose (1–20 kGy) gamma irradiation of silver nitrate in the presence of graphene-based material (graphene oxide or electrochemically exfoliated graphene). The large surface area of those graphene-based materials combined with the presence of oxygen-containing functional groups on the surface provided successful nucleation and growth of Ag nanoparticles, which resulted in a uniformly covered graphene surface. The obtained Ag nanoparticles were spherical with a predominant size distribution of 10–50 nm for graphene oxide and 10–100 nm for electrochemically exfoliated graphene. The photothermal efficiency measurement showed a temperature increase upon exposure to a 532 nm laser for all samples and the highest photothermal efficiency was measured for the graphene oxide/Ag NP sample prepared at 5 kGy. Electromagnetic interference (EMI) shielding efficiency measurements showed poor shielding for the composites prepared with graphene oxide. On the other hand, all composites prepared with electrochemically exfoliated graphene showed EMI shielding to some extent, and the best performance was measured for the samples prepared at 5 and 20 kGy doses. [ABSTRACT FROM AUTHOR]

This document provides information on the use of chloride ion titration as a method for teaching quantitative analysis in schools. It discusses the safety concerns associated with using toxic potassium chromate as an indicator and proposes using phosphate as a safer alternative. The text explains the dynamics of precipitation reactions and the factors that influence the solubility of salts. It also introduces the Mohr titration method and discusses the properties of various silver salts that can be used as substitutes for silver chromate. The goal is to find a suitable substitute for silver chromate that can reliably indicate the equivalence point in a titration. Sodium phosphate is suggested as a safe alternative for chloride ion titration, but it is not suitable for the quantitative determination of bromide and iodide ions. [Extracted from the article]

Bacterial plant diseases are difficult to control as the durability of deployed control measures is thwarted by continuous and rapid changing of bacterial populations. Although application of copper compounds to plants is the most widespread and inexpensive control measure, it is often partially efficacious for the frequent appearance of copper-resistant bacterial strains and it is raising concerns for the harmful effects of copper on environment and human health. Consequently, European Community included copper compounds in the list of substances candidates for substitution. Nanotechnologies and the application of nanoparticles seem to respond to the need to find new very effective and durable measures. We believe that Argirium-SUNCs®, silver ultra nanoclusters with an average size of 1.79 nm and characterized by rare oxidative states (Ag2+/3+), represent a valid candidate as a nano-bactericide in the control of plant bacterial diseases. Respect to the many silver nanoparticles described in the literature, Argirium-SUNCs have many strengths due to the reproducibility of the synthesis method, the purity and the stability of the preparation, the very strong (less than 1 ppm) antimicrobial, and anti-biofilm activities. In this mini-review, we provide information on this nanomaterial and on the possible application in agriculture. Key points: • Argirium-SUNCs have strong antimicrobial activities against phytopathogenic bacteria. • Argirium-SUNCs are a possible plant protection product. • Argirium-SUNCs protect tomato plants against bacterial speck disease. [ABSTRACT FROM AUTHOR]

A highly efficient, novel, two‐phase liquid method using phase transfer catalyst is reported to prepare β‐lactam‐conjugated silver nanoparticles as an approach to improve antibacterial activity of β‐lactams. In the method assisted by cetyltrimethylammonium bromide, NaBH4 reduced AgNO3 producing silver NPs that are coated with β‐lactams. The studies conducted provide a generalized method applicable to all types of β‐lactam substrates for capping on silver NPs. The NPs have been characterized by UV–Visible, Fourier transform infrared spectroscopy, x‐ray diffraction, transmission electron microscopy, and dynamic light scattering methods. [ABSTRACT FROM AUTHOR]

Many products contain silver nanoparticles, which are adsorbed by living organisms and then go through biological barriers. In particular, penetration of silver nanoparticles through the placental barrier is likely to damage the offspring. Here, we review hazards of silver nanoparticles with focus on exposure during pregnancy, toxicokinetics at maternal and fetal layers, ex vivo and in vivo placenta transfer models, and factors affecting the transfer. Exposure occurs by oral uptake, inhalation, dermal contact, and systemic administration. Toxicokinetics include absorption, distribution in tissues, metabolism and excretion. The accumulation efficiency is primarily influenced by the mode of exposure. Injection exhibits the highest bioavailability, followed by inhalation and oral uptake. Particles within the range of tens of nanometers are capable of crossing the placenta, according to an ex vivo placental perfusion model. In contrast, larger particles in the range of hundreds of nanometers are expelled outside. Due to the size restriction of the trophoblast channel, which typically ranges from 15 to 25 nm, it is possible for silver nanoparticles with an average size of around 20 nm to passively enter the placenta through the pericellular pathway, such as diffusion. On the other hand, larger silver nanoparticles may be delivered to the placenta through endocytosis, which can occur via phagocytosis, receptor-mediated or independent mechanisms. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (MNPs) have gained significant attention due to their multifunctional properties and broad applications in various fields. In this study, we present a novel and sustainable approach for the synthesis of silver nanoparticles (AgNPs) using waste materials, dried banana pith extract (BPE) and rice water. The synthesised AgNPs exhibit a size of 43 nm and zeta potential of −24.1 mV. A maximum temperature rise of 4°C with an efficiency of 41% is achieved within a short time by the photothermal activity. The qualitative colorimetric detection of Fe3+ and its quantitative spectroscopic detection are achieved in a linear detection range of 20–80 μM and with a limit of detection of 8.5 μM. The sensing mechanism is explained in terms of cooperative binding of Fe3+ ions to BPE-AgNPs. A homogeneous, flexible and stable AgNP-rice starch gel is formed. The work offers environmentally conscious nanomaterials for diverse applications. [ABSTRACT FROM AUTHOR]

Diabetic wounds are prone to develop chronic wounds due to bacterial infection and persistent inflammatory response. However, traditional dressings are monofunctional, lack bioactive substances, have limited bacterial inhibition as well as difficulties in adhesion and retention. These limit the therapeutic efficacy of traditional dressings on diabetic wounds. Therefore, finding and developing efficient and safe wound dressings is currently an urgent clinical need. In this study, an antimicrobial gel loaded with silver nanoparticles (AgNPs) (referred to as AgNPs@QAC-CBM) was prepared by crosslinking quaternary ammonium chitosan (QAC) with carbomer (CBM) as a gel matrix. AgNPs@QAC-CBM exhibited a reticulated structure, strong adhesion, good stability, and remarkable bactericidal properties, killing 99.9% of Escherichia coli, Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa within 1 min. Furthermore, AgNPs@QAC-CBM improved the wound microenvironment and accelerated wound healing in diabetic mice by promoting tissue production and collagen deposition, inducing M2 macrophages, reducing pro-inflammatory factor secretion and increasing anti-inflammatory factor levels. Moreover, AgNPs@QAC-CBM was proven to be safe for use through skin irritation and cytotoxicity tests, as they did not cause any irritation or toxicity. To summarize, AgNPs@QAC-CBM showed promising potential in enhancing the diabetic wound healing process. [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]

With the extensive utilization of nanotechnology, silver nanoparticles (AgNPs) are prevalent nanomaterials that may entail ecological risks by their potential translocation into plant systems. The present study investigated the physiological and molecular responses of basil seedlings (Ocimum basilicum) subjected to AgNPs or silver nitrate (AgNO3) for 7 days. The seedlings were treated with 0, 4, 10, or 40 mg/L of AgNO3 or AgNPs in Hoagland's solution. Both treatments resulted in significant accumulation of Ag in the roots and shoots, with higher levels in the roots of AgNO3-treated seedlings. AgNPs increased plant biomass at 4 mg/L, while AgNO3 decreased it at all concentrations. Both treatments reduced the total chlorophyll, carotenoids, and carbohydrates, with more pronounced effects in AgNO3-treated seedlings. Both treatments also induced oxidative stress, as indicated by increased levels of H2O2, malondialdehyde (MDA), and proline, and enhanced activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). However, these responses were more evident in AgNO3-treated seedlings, especially at higher concentrations. Quantitative real-time PCR analysis revealed that both treatments induced the upregulation of genes encoding oxidative stress tolerance-related enzymes, such as FSD1, MSD1, CSD1, CATa, CATb, APXa and APXb, in the basil seedling shoots. These results suggest that AgNPs are less toxic to basil plants than AgNO3 and that basil plants can activate physiological and molecular mechanisms to cope with Ag-induced oxidative stress. [ABSTRACT FROM AUTHOR]

The unearthing of various forms of broad and narrow-spectrum antibiotics have helped mankind combat various forms of microbic infections ranging from protozoal to bacterial. The applicability of antibiotics has been decisive in a wide range of frontline therapeutic dealings. An extensive use of antibiotics and certain genetic modifications in microbes has paved the way for a new issue to be answered by the scientific community, an antibiotic resistance. An unparallel infections triggered by multidrug-resistant organisms (MDRO) account to be a major cause of mortality and morbidity, today this situation demands the development of alternative strategies of cure and medicine by the scientific community. Study shows the amplification of the effect of antibiotics may be a possible route to address antibiotic resistivity. The assortment of various surface properties of nanoparticles (NPs) coupled with their ability to efficiently bind with bacterial surfaces leading to the rupture and lysis of cell deliberates potential strategies to manage infections caused by MDROs.The present study scrutinizes the amplification of the antibacterial activity of ciprofloxacin (CIP) against the bacterial strains of Staphylococcus aureus, Escherichia coli, Pseudomonas and Streptococcus mutans on coupling with synthesized copper, silver and zinc oxide NPs (ZnO NPs) by disc diffusion technique. The current study describes the efficacious synthesis and characterization of ZnONP, copper Nps (CuNPs) and silver NPs (AgNPs) followed by the induced amplification of the antibacterial activity of CIP by coupling it with synthesized metal/metal oxide (M/MO NP). The synthesized M/MO NPs were characterized using XRD and FE-SEM studies and TEM. The results indicated that among the ZnONP, AgNP, the Cu NPs potentiate the bactericidal efficacy of CIP antibiotics. [ABSTRACT FROM AUTHOR]

In this study, we harnessed the properties of desert plants to synthesize silver nanoparticles to explore potential antimicrobial solutions. Chrozophora plicata and Heliotropium curassavicum extracts were used as green reducing agents to transform silver ions into nanoparticles. Our findings revealed novel properties of C. plicata, which have not been reported before. Surface plasmon resonance peak at 453.6 and 431 nm for C. plicata and H. curassavicum, respectively, via ultraviolet (UV) spectral analysis evidenced the successful fabrication of silver nanoparticles with particle sizes ranging from 4.3-8 and 3.1-6.97 nm respectively, which was validated by field emission scanning electron microscopy (FE-SEM). X-ray diffraction analysis revealed that the crystal structure of these nanoparticles had a face-centered cubic geometry. Fourier transform infrared spectrometry of the plant extract showed strong signals corresponding to carbohydrates, proteins, and phenolics. Antibacterial assays of the silver nanoparticles from C. plicata displayed zones of inhibition at 5 and 4 mm against Staphylococcus aureus and Escherichia coli, respectively. Meanwhile, the silver nanoparticles from H. curassavicum exhibited zones of inhibition against both pathogens at 10 and 7 mm, respectively. The test samples were substantial inhibitors of S. aureus and E. coli biofilm formation since these displayed IC50 values in the range of 8.88-10.57 mg/mL, which is as potent as the reference ciprofloxacin. Consequently, the silver nanoparticles derived from these desert plants can be potential drug candidates for treating respiratory and digestive tract infections alone or in combination with existing antibiotics. [ABSTRACT FROM AUTHOR]

An environmentally feasible approach was adopted for the green synthesis of silver nanoparticles (AgNPs) in the BC membrane using Komagataeibacter intermedius (MBS-88) strain. BC production was optimized, resulting in 14.72 g/L of BC when crude glycerol was utilized as a carbon source. The produced BC has a tensile strength of 387 N/m2, an elongation at break % of 2.04, and a Young's modulus of 304 MPa. The bacterial cellulose/AgNP composites have been successfully synthesized using BC as a template via the hydrothermal synthesis in which bacterial cellulose itself acts as a reducing and stabilizing agent. The characterization of the synthesized AgNPs was carried out using electron microscopy (SEM and TEM), Fourier transform infrared microscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Adherence of AgNPs to the surface of the BC matrix was observed under SEM. Particle size distribution shows nanoparticles are in the range of 5–45 nm. XRD shows AgNPs peaks at 38.2° (111), 46.3° (200), and 64.5° (220). Peaks of Ag 3d at 367.58 eV and 373.55 eV, along with C 1 s at 284.26 eV and O 1 s at 532.16 eV, were observed in XPS spectra. BC/Ag nanocomposite disk showed better antibacterial activities against Staphylococcus epidermidis ATCC 2228 (6.5 ± 0.1 mm), Staphylococcus aureus 29,213 (6 ± 0.2 mm), and Pseudomonas aeruginosa (5.1 ± 0.2 mm). Thus, the synthesized BC–AgNPs could be used in controlling wound infections as an alternative to chemical synthesis that might have deleterious effects on the ecosystem. [ABSTRACT FROM AUTHOR]

To synthesize silver nanoparticles suspended in deionized water, Elettaria cardamomum (Car) seed extract and Car@Ag nanoparticles were prepared in three steps. The first used a hot aqueous extract of Elettaria cardamomum seed, and then, the second used pulsed laser ablation technique (PLAL) by Nd:YAG laser (λ = 1064 nm wavelength) at laser energy of 400 mJ, and the number of pulses was 500 pulses and third step for the synthesis of creating a non-conjugated Elettaria cardamomum extract. Ultraviolet visible (UV–Vis) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) were used to investigate the optical, structural, and morphological characterizations of synthesized Car@AgNPs. The nanoparticles were spherical in shape, and a size distribution exhibited a mean size of 21 nm, according to the TEM findings. AgNPs and Car@AgNPs have free radical scavenging activity in the DPPH assay. Additionally, Car@AgNPs were examined in vitro for zones of inhibition against pathogenic bacteria like Escherichia coli and Staphylococcus aureus. The inhibition rate of Escherichia coli was higher than that observed in Staphylococcus aureus. Finally, Car@AgNPs demonstrated a potential cytotoxicity agent breast cancer (MCF-7) cell line that was evaluated by MTT assay. [ABSTRACT FROM AUTHOR]

Pesticides play an important role in conventional agriculture. Yet, their harmful effects on the environment are becoming increasingly apparent. The occurrence of pesticides is hence being monitored worldwide. For fast, easy, yet sensitive identification, surface-enhanced Raman spectroscopy (SERS) is a powerful tool. In this study, a method is introduced that may be amended to in-field detection of pesticides. Gold and silver nanoparticles were synthesized, size-tailored, and characterized. The herbicide paraquat and the fungicide thiram served as model compounds. The preparation yielded reproducible SERS spectra. Using quantum chemical computation, Raman and SERS spectra were calculated and analyzed. The interpretation of vibrational modes in combination with SERS enhancement and attenuation allowed us to identify compound-specific bands. The assignment was interpreted in terms of the orientation of paraquat and thiram on the gold and silver nanoparticle surfaces. Paraquat preferred a co-planar arrangement parallel to the gold nanoparticle surface and a head-on orientation on the silver nanoparticle. For thiram, breaking of the disulfide bond was recognized, such that interaction with the surface occurred via the sulfur atoms. Successful detection of the pesticides after recollection from vegetable leaves demonstrated the method's applicability for pesticide identification. [ABSTRACT FROM AUTHOR]

The increasing prevalence of Botrytis cinerea infections has accelerated the need for effective antifungal agents. Traditional chemical methods are often associated with environmental harm, making the green synthesis of nanoparticles an attractive alternative. This study aimed to synthesize and characterize silver nanoparticles (AgNPs) using extracts from three medicinal plants - Amaranthus viridis L., Mentha piperita L., and Ocimum basilicum L. - and evaluate their antifungal efficacy against Botrytis cinerea. AgNPs were synthesized using methanol extracts of the selected plants and characterized by Scanning Electron Microscopy (SEM), UV-visible spectroscopy, X-ray diffraction analysis (XRD), and Fourier-Transform Infrared Spectroscopy (FTIR). The synthesized AgNPs exhibited peak UV-visible absorption at 425 nm, 400 nm, and 420 nm, and had average particle sizes of 1.2 nm, 21.5 nm, and 358 nm for A. viridis, M. piperita, and O. basilicum, respectively. At a concentration of 3%, the AgNPs inhibited B. cinerea growth by 51%, 40.4%, and 39%. Further, an ethyl acetate fraction from A. viridis displayed 50% fungal inhibition at a concentration of 0.20%. GC-MS analysis revealed 15 bioactive compounds in the extracts. The study confirms that AgNPs synthesized from medicinal plants exhibit significant antifungal properties, making them potential candidates for the development of eco-friendly antifungal agents. The findings offer a green and sustainable avenue for the development of new antifungal agents and suggest further studies to optimize the synthesis process and investigate the mechanisms of action. [ABSTRACT FROM AUTHOR]

Herein, a convenient and environment-friendly reduction strategy was employed to attach silver nanoparticles onto ceria nanorods (AgCe). Nanorods were synthesised through a green chemistry approach with varied silver contents and Citrus maxima peel extract as a reducing agent. The resulting AgCe nanocomposites were evaluated for their efficacy in reducing methyl orange (MO) at ambient temperature by employing NaBH4 as a protonating agent. The as-prepared samples were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray energy-dispersive spectroscopy, Raman spectroscopy, Brunauer–Emmett–Teller method, and high-resolution transmission electron microscopy. The as-prepared sample exhibited outstanding activity on the catalytic reduction of MO, and the synergistic effect between Ag nanoparticles and CeO2 nanorods was proved. Silver nanoparticles were formed and dispersed well on the surface of ceria nanorods. Based on the UV–Vis results, the activity of the samples with silver was superior to that of pure ceria. The 0.2AgCe sample was the most effective when the catalyst concentration was 0.08 g/L, and the molar ratio between MO and NaBH4 was 1/200. The entire catalytic reduction was thought to follow pseudo-first-order kinetics. Hence, Ag nanoparticles decorated on CeO2 efficiently offered excellent catalytic efficiency and stability in MO reduction and that the catalyst was suitable for practical applications, such as wastewater treatment. [ABSTRACT FROM AUTHOR]

In this study, the biosynthesis and characterization of silver nanoparticles (AgNPs) from orchid tree (Bauhinia variegata) leaf extract were firstly carried out, and then, the usability of AgNPs as a colorimetric sensor for detection of Fe3+ ions in aqueous solutions was evaluated. The characterization studies showed that the synthesized particles were determined to be AgNPs in nanoscale and face-centered cubic structure. Besides, the total phenolic content of B. variegata extract was determined to be 1.826 ± 2.1 mg gallic acid equivalents/g dry leaf. Also, the biosynthesized AgNPs showed a strong surface plasmon resonance (λSPR) around 430 nm and λSPR intensity decreased with the increasing in Fe3+ concentration in aqueous solution. Based on the linear relationship between the change of λSPR intensity and Fe3+ ion concentration, AgNPs can be used for the sensitive and selective detection of Fe3+ ions in aqueous solutions with a linear range of 6-100 μM and a detection limit of 2.08 × 10−6 M. [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]

Cassava root rot disease caused by the fungal pathogens Fusarium solani and Lasiodiplodia theobromae produces severe damages on cassava production. This research was conducted to produce and assess silver nanoparticles (AgNPs) synthesized by Trichoderma harzianum for reducing root rot disease. The results revealed that using the supernatants of T. harzianum on a silver nitrate solution changed it to reddish color at 48 h, indicating the formation of AgNPs. Further characterization was identified using dynamic light scattering (DLS) and scanning electron microscope (SEM). DLS supported that the Z-average size is at 39.79 nm and the mean zeta potential is at − 36.5 mV. SEM revealed the formation of monodispersed spherical shape with a diameter between 60–75 nm. The antibacterial action of AgNPs as an antifungal agent was demonstrated by an observed decrease in the size of the fungal colonies using an increasing concentration of AgNPs until the complete inhibition growth of L. theobromae and F. solani at > 58 µg mL−1 and at ≥ 50 µg mL−1, respectively. At in vitro conditions, the applied AgNPs caused a decrease in the percentage of healthy aerial hyphae of L. theobromae (32.5%) and of F. solani (70.0%) compared to control (100%). The SR-FTIR spectra showed the highest peaks in the first region (3000–2800 cm−1) associated with lipids and fatty acids located at 2962, 2927, and 2854 cm−1 in the AgNPs treated samples. The second region (1700–1450 cm−1) consisting of proteins and peptides revealed the highest peaks at 1658, 1641, and 1548 cm−1 in the AgNPs treated samples. The third region (1300–900 cm−1), which involves nucleic acid, phospholipids, polysaccharides, and carbohydrates, revealed the highest peaks at 1155, 1079, and 1027 cm−1 in the readings from the untreated samples. Finally, the observed root rot severity on cassava roots treated with AgNPs (1.75 ± 0.50) was significantly lower than the control samples (5.00 ± 0.00). [ABSTRACT FROM AUTHOR]

AbstractVarious methods have been used to treat Alzheimer’s disease, but recently, the use of medicinal plants and the combination of their extracts and active substances with nanoparticles have been considered. Determination of anti-Alzheimer properties of silver nanoparticles synthesized by the Pimpinella anisum seed extract may be the novelty of this research. Nanoparticles were confirmed by UV–Vis, FTIR, SEM, EDAX, TEM, DLS, and XRD analysis. The antioxidant effects were determined by DPPH and ABTS and the inhibitory effects on the production of amyloid nanofibrils were determined by Congored assay. Nanoparticles were spherical with a diameter ranging from 40 to 60 nm. The highest antioxidant effect was observed at 500 and the highest inhibition of amyloid production was observed at 100 μg/mL of nanoparticles. Anise-AgNPs with antioxidant and inhibitory properties for amyloid production could be introduced as a suitable candidate for reducing the side effects of Alzheimer’s disease. [ABSTRACT FROM AUTHOR]

Aloe perryi has been studied and possesses several activities, including antibacterial, antiparasitic, and anticancer properties. In this study, A. perryi was used as a reducing agent of silver ions into silver nanoparticles. Aloe perryi–silver nanoparticles (APS‐NPs) were characterized and evaluated using characterization techniques. However, the antioxidative, antibacterial, and anticancer assays were studied to evaluate the pharmacological activities of APS‐NPs. APS‐NPs were developed and changed to dark brown and the maximum absorption was 442 nm. SEM (5–583 nm), TEM (4–110 nm), XRD (21.84 nm), and zeta potential analysis (63.39 nm) revealed that the APS‐NPs were nano‐sized, and the APS‐NPs had a cubic crystalline structure, according to the XRD results. FTIR analysis suggested that functional groups of A. perryi metabolites were involved in forming APS‐NPs. The zeta potential indicated that the APS‐NPs were negatively charged (−32 mV), suggesting good stability. APS‐NPs showed significant antioxidative stress activity by reducing DPPH‐free radicles in a dose‐dependent manner. APS‐NPs‐induced antibacterial effect against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Acinetobacter baumannii (A. baumannii). APS‐NPs reduced the cell viability and cell migration of the human colon tumor cell line (HCT 116) compared with controls, indicating that APS‐NPs could play a role in reducing metastasis and inducing cell apoptosis against colon cancer. In conclusion, the nanoparticle synthesis from A. perryi extract demonstrated excellent antioxidant, antibacterial, and anticancer activities, thus suggesting that our APS‐NPs have the potential to be used as antioxidative and antibacterial in food and pharmaceutical industries. [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 study investigates the antiviral efficacy of chitosan‐stabilized silver nanoparticles (AgNPs) against the Foot‐and‐Mouth Disease virus (FMDV), a highly contagious pathogen affecting cloven‐hoofed animals. In vitro experiments demonstrated that AgNPs effectively inhibited FMDV replication in a dose‐dependent manner. At a concentration of 1.56 μg/ml, AgNPs exhibited no cytotoxicity to baby hamster kidney 21 (BHK21) cells while achieving complete deactivation of FMDV at a titer of 103 TCID50 and inhibiting viral growth at a titer of 104 TCID50. These findings suggest the potential of silver nanoparticles as a novel disinfectant for controlling FMDV transmission and preventing disease outbreaks. [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]

Infectious diseases are becoming a worldwide threat due to antibiotic resistance. Therefore, it is necessary to prepare innovative antibiotics against bactericidal activities. The development of nanomedicine has been greatly aided by nanotechnology. A focal point of exploration involves the production of noble metal nanoparticles, owing to their diverse applications. The study's subjects are the synthesis, characterization, and assessment of silver nanoparticles (AgNPs) derived from Berberis lyceum Royle root bark (BLR) extract. The study revealed the potent antibacterial properties of BLR‐AgNPs, with heightened efficacy against S. pyogenes (16.7±0.3 mm) and comparatively lower activity against E. coli (1.1±0.1 mm). Minimum inhibitory concentration assessment indicated maximum activity at 10 μg/mL, whereas 2.5 μg/mL demonstrated the least inhibitory effect. Furthermore, the wound healing potential of BLR‐AgNPs was explored, demonstrating superior activity (0.19±0.02 cm) equated to BLR‐extract (0.46±0.02 cm) and untreated wounds (0.77±0.02 cm). These findings underscore the considerable antibacterial and wound‐healing capabilities of BLR‐AgNPs. [ABSTRACT FROM AUTHOR]

AbstractFor the first time, methanolic leaf extract of the hydrophyte Persicaria senegalensis L. was evaluated for its ability to silver nanoparticles (AgNPs) biosynthesis. The effect of stirring time and plant extract concentrations was studied. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used for characterization of AgNPs. XRD confirmed the AgNPs formation with crystallite size in the range 23–71 nm. The crystallite size increased with increasing both stirring time and plant extract concentration. Antioxidants, including secondary metabolites such as flavonoids and phenols are substances that inhibit oxidative damage to the cell organisms by scavenging the free radicals and thus reducing the hazard of diseases. The scavenging and antioxidant activities of the plant leaf extract and AgNPs were evaluated and exhibited potent antioxidant activity. The total antioxidant capacity (TAC) of plant leaf extract and AgNPs was 52.41 and 10.13 µg AA equivalent/mg DW, respectively. Total phenolics (TPs) and total flavonoids (TFs), revealed high contents equal to 154.83 µg gallic acid equivalent and 100.05 µg quercetin equivalent/mg DW plant extract, respectively. [ABSTRACT FROM AUTHOR]