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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]

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]

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]

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]

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]

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]

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]

Nosocomial infections represent a major threat within healthcare systems worldwide, underscoring the critical need for materials with antimicrobial properties. This study presents the development of polyurethane foam embedded with silver nanoparticles (PUF/AgNPs) using a rapid, eco-friendly, in situ radiochemical synthesis method. The nanocomposites were characterized by UV–vis and FTIR spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray technique (SEM/EDX), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile and compression strengths, antimicrobial activity, and foam toxicity tests. The resulting PUF/AgNPs demonstrated prolonged stability (over 12 months) and good dispersion of AgNPs. Also, the samples presented higher levels of hardness compared to samples without AgNPs (deformation of 1682 µm for V1 vs. 4307 µm for V0, under a 5 N force), tensile and compression strength of 1.80 MPa and 0.34 Mpa, respectively. Importantly, they exhibited potent antimicrobial activity against a broad range of bacteria (including Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis) and a fungal mixture (no fungal growth on the sample surface was observed after 28 days of exposure). Furthermore, these materials were non-toxic to human keratinocytes, which kept their specific morphology after 24 h of incubation, highlighting their potential for safe use in biomedical applications. We envision promising applications for PUF/AgNPs in hospital bed mattresses and antimicrobial mats, offering a practical strategy to reduce nosocomial infections and enhance patient safety within healthcare facilities. [ABSTRACT FROM AUTHOR]

Metal nanoparticle phytosynthesis has become, in recent decades, one of the most promising alternatives for the development of nanomaterials using "green chemistry" methods. The present work describes, for the first time in the literature, the phytosynthesis of silver nanoparticles (AgNPs) using extracts obtained by two methods using the aerial parts of Marrubium vulgare L. The extracts (obtained by classical temperature extraction and microwave-assisted extraction) were characterized in terms of total phenolics content and by HPLC analysis, while the phytosynthesis process was confirmed using X-ray diffraction and transmission electron microscopy, the results suggesting that the classical method led to the obtaining of smaller-dimension AgNPs (average diameter under 15 nm by TEM). In terms of biological properties, the study confirmed that AgNPs as well as the M. vulgare crude extracts reduced the viability of human gingival fibroblasts in a concentration- and time-dependent manner, with microwave-assisted extracts having the more pronounced effects. Additionally, the study unveiled that AgNPs transiently increased nitric oxide levels which then decreased over time, thus offering valuable insights into their potential therapeutic use and safety profile. [ABSTRACT FROM AUTHOR]

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

Some composite materials have been prepared, constituted by a cyclodextrin-bis-urethane-based nanosponge matrix in which a reduced graphene oxide/silver nanoparticles photocatalyst has been dispersed. Different chain extenders were employed for designing the nanosponge supports, in such a way as to decorate their hyper-cross-linked structure with diverse functionalities. Moreover, two different strategies were explored to accomplish the silver loading. The obtained systems were successfully tested as catalysts for the photodegradation of emerging pollutants such as model dyes and drugs. Enhancement of the photoactive species performance (up to nine times), due to the synergistic local concentration effect exerted by the nanosponge, could be assessed. Overall, the best performances were shown by polyamine-decorated materials, which were able to promote the degradation of some particularly resistant drugs. Some methodological issues pertaining to data collection are also addressed. [ABSTRACT FROM AUTHOR]

This work aims to analyze the influence of selected plants on the synthesis of silver nanoparticles (AgNPs). Six plants were chosen for the experiment, from which extracts were prepared: maclura fruit, spruce and ginkgo needles, green algae (Ch. kessleri), and mushrooms, namely Collybia nuda, and Macrolepiota procera. The composition of the extracts and colloids after preparation of the nanoparticles was analyzed using FTIR analysis. The composition of the extracts affected not only the rate of the synthesis but also the shape of the nanoparticles. TEM analysis confirmed the synthesis of mainly spherical nanoparticles (size range: 10–25 nm). However, triangular prisms and polyhedral nanoparticles synthesized by the extracts containing mainly flavonoids, terpenes, and phenols (the main compounds of resins) were also confirmed. EDS analysis was used to analyze the composition of the nanoparticles. It was proven that by choosing the right plant extract and using the appropriate technology with extract treatment, it is possible to prepare nanoparticles of different shapes. [ABSTRACT FROM AUTHOR]

Metal and metal oxide nanostructured materials have been chemically and physically characterized and tested concerning methylene blue (MB) photoremoval and UV antibacterial activity against Escherichia coli and Staphylococcus aureus. In detail, silver nanoparticles and commercial BaTiO3 nanoparticles were modified to obtain nanocomposites through sonicated sol–gel TiO2 synthesis and the photodeposition of Ag nanoparticles, respectively. The characterization results of pristine nanomaterials and synthetized photocatalysts revealed significant differences in specific surface area (SSA), the presence of impurities in commercial Ag nanoparticles, an anatase phase with brookite traces for TiO2-based nanomaterials, and a mixed cubic–tetragonal phase for BaTiO3. Silver nanoparticles exhibited superior antibacterial activity at different dosages; however, they were inactive in the photoremoval of the dye. The silver–TiOx nanocomposite demonstrated an activity in the UV photodegradation of MB and UV inhibition of bacterial growth. Specifically, TiO2/AgNP (30–50 nm) reduced growth by 487.5 and 1.1 × 103 times for Escherichia coli and Staphylococcus aureus, respectively, at a dose of 500 μg/mL under UV irradiation. [ABSTRACT FROM AUTHOR]

The review article emphasizes the silver nanoparticles (AgNPs)/gold nanoparticles (AuNPs) decorated graphene oxide (GO)/functionalized carbon nanotubes (f-CNTs) hybrid nanofillers reinforced polyaniline (PANI) ternary nanocomposites due to their extraordinary properties and multifunctional applications as compare to the individual components. Conducting polymer nanocomposites are used in various applications due to the synergic effect that enhances various properties of the individual components. Owing to the elevated thermal, optical, sensing, and dielectric properties of the nanocomposites that revealed as an effective material, which can be employed for the application in energy storage devices like solar cells, batteries, supercapacitors, sensing of heavy metal ions, etc. [ABSTRACT FROM AUTHOR]

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

To achieve the environmentally friendly and rapid green synthesis of efficient and stable AgNPs for drug-resistant bacterial infection, this study optimized the green synthesis process of silver nanoparticles (AgNPs) using Dihydromyricetin (DMY). Then, we assessed the impact of AgNPs on zebrafish embryo development, as well as their therapeutic efficacy on zebrafish infected with Methicillin-resistant Staphylococcus aureus (MRSA). Transmission electron microscopy (TEM) and dynamic light-scattering (DLS) analyses revealed that AgNPs possessed an average size of 23.6 nm, a polymer dispersity index (PDI) of 0.197 ± 0.0196, and a zeta potential of −18.1 ± 1.18 mV. Compared to other published green synthesis products, the optimized DMY-AgNPs exhibited smaller sizes, narrower size distributions, and enhanced stability. Furthermore, the minimum concentration of DMY-AgNPs required to affect zebrafish hatching and survival was determined to be 25.0 μg/mL, indicating the low toxicity of DMY-AgNPs. Following a 5-day feeding regimen with DMY-AgNP-containing food, significant improvements were observed in the recovery of the gills, intestines, and livers in MRSA-infected zebrafish. These results suggested that optimized DMY-AgNPs hold promise for application in aquacultures and offer potential for further clinical use against drug-resistant bacteria. [ABSTRACT FROM AUTHOR]

The treatment of chronic wounds involves precise requirements and complex challenges, as the healing process cannot go beyond the inflammatory phase, therefore increasing the healing time and implying a higher risk of opportunistic infection. Following a better understanding of the healing process, oxygen supply has been validated as a therapeutic approach to improve and speed up wound healing. Moreover, the local implications of antimicrobial agents (such as silver-based nano-compounds) significantly support the normal healing process, by combating bacterial contamination and colonization. In this study, silver (S) and tannylated calcium peroxide (CaO2@TA) nanoparticles were obtained by adapted microfluidic and precipitation synthesis methods, respectively. After complementary physicochemical evaluation, both types of nanoparticles were loaded in (Alg) alginate-based gels that were further evaluated as possible dressings for wound healing. The obtained composites showed a porous structure and uniform distribution of nanoparticles through the polymeric matrix (evidenced by spectrophotometric analysis and electron microscopy studies), together with a good swelling capacity. The as-proposed gel dressings exhibited a constant and suitable concentration of released oxygen, as shown for up to eight hours (UV–Vis investigation). The biofilm modulation data indicated a synergistic antimicrobial effect between silver and tannylated calcium peroxide nanoparticles, with a prominent inhibitory action against the Gram-positive bacterial biofilm after 48 h. Beneficial effects in the human keratinocytes cultured in contact with the obtained materials were demonstrated by the performed tests, such as MTT, LDH, and NO. [ABSTRACT FROM AUTHOR]

Metal nanoparticle synthesis via environmentally friendly methods is gaining interest for their potential advantages over conventional physico-chemical approaches. Herein, we propose a robust green synthesis route for lignin-modified silver nanoparticles, utilizing the recovery of lignin as a renewable raw material and exploring its application in valuable areas. Through a systematic approach combining UV-Vis spectroscopy with AAS and DLS, we identified repeatable and scalable reaction conditions in an aqueous solution at pH 11 for homogeneous silver nanoparticles with high uniformity. The TEM median sizes ranged from 12 to 15 nm with circularity between 0.985 and 0.993. The silver nanoparticles yield exceeded 0.010 mol L−1, comparable with traditional physico-chemical methods, with a minimal loss of silver precursor ranging between 0.5 and 3.9%. Characterization by XRD and XPS revealed the presence of Ag-O bonding involving lignin functional groups on the pure face-centered cubic structure of metallic silver. Moreover, the lignin-modified silver nanoparticles generated a localized thermal effect upon near-infrared laser irradiation (808 nm), potentially allowing for targeted applications in the biomedical field. Our study showcases the potential of lignin as a renewable reducing and capping agent for silver nanoparticle synthesis, addressing some shortcomings of green synthesis approaches and contributing to the development of suitable nanomaterials. [ABSTRACT FROM AUTHOR]

AbstractNanoparticles (NPs) have played a pivotal role in various biomedical applications, spanning from sensing to drug delivery, imaging and anti-viral therapy. The therapeutic utilisation of NPs in clinical trials was established in the early 1990s. Silver nanoparticles (AgNPs) possess anti-microbial, anti-cancer and anti-viral properties, which make them a possible anti-viral drug to combat the COVID-19 virus. Free radicals and reactive oxygen species are produced by AgNPs, which causes apoptosis induction and prevents viral contamination. The shape and size of AgNPs can influence their interactions and biological activities. Therefore, it is recommended that silver nanoparticles (AgNPs) be used as a valuable tool in the management of COVID-19 pandemic. These nanoparticles possess strong anti-microbial properties, allowing them to penetrate and destroy microbial cells. Additionally, the toxicity level of nanoparticles depends on the administered dose, and surface modifications are necessary to reduce toxicity, preventing direct interaction between metal surfaces and cells. By utilising silver nanoparticles, drugs can be targeted to specific areas in the body. For example, in the case of COVID-19, anti-viral drugs can be stimulated as nanoparticles in the lungs to accelerate disease recovery. Nanoparticle-based systems have the capability to transport drugs and treat specific body parts. This review offers an examination of silver nanoparticle-based drug delivery systems for combatting COVID-19, with the objective of boosting the bioavailability of existing medications, decreasing their toxicity and raising their efficiency. [ABSTRACT FROM AUTHOR]

This study evaluated the efficacy of phytogenic silver and zinc nanoparticles in improving heat resilience in various wheat varieties. The silver and zinc nanoparticles were synthesized using plant leaf extract and characterized using various techniques. Four wheat varieties (DBW187, Black Wheat, DBW 50, and PBW 621) were subjected to field trials. The random block design was used, and nanoparticles in different concentrations were applied at various growth stages and morphologically, and yield parameters were recorded. UV–vis spectroscopy spectral analysis showed peaks for Ag nanoparticles at 420 nm wavelength and Zn nanoparticles at 240 and 350 nm wavelength, depicting the preliminary confirmation of nanoparticle synthesis. Electron microscopic analysis (TEM and SEM) provided morphological insights and confirmed synthesis of fine-sized particle mostly in a range between 10 and 60 nm. Energy dispersive x-ray analysis confirmed the elemental composition of the synthesized nanoparticles, with Ag and Zn elements detected in their respective samples. It also confirmed the oxide nature of synthesized ZnNPs. Dynamic light scattering analysis provided size distribution profiles, indicating average sizes of approximately 61.8 nm for Ag nanoparticles and 46.5 nm for Zn nanoparticles. The concentrations of Ag and Zn nanoparticles in the samples were found to be 196.3 ppm and 115.14 ppm, respectively, through atomic absorption spectroscopic analysis. Fourier transform infrared spectroscopy analysis revealed characteristic functional groups present in the nanoparticles. The results of field experiments established that Ag nanoparticles at 75 ppm concentration exhibited the most significant enhancements in plant growth. Conversely, Zn nanoparticles at a 100 ppm concentration demonstrated the most substantial improvements in the growth and yield of heat-stressed wheat varieties. The study concludes that optimized concentrations of silver and zinc nanoparticles can effectively improve heat stress resilience in wheat. These findings are promising to enhance abiotic stress resilience in crops. [ABSTRACT FROM AUTHOR]