Ratio Of AgNO3 Research Articles

Synthesis of Silver Nanoparticles with <i>Syzygium aromaticum</i> Leaves Extract as Antioxidant and Antimicrobial Materials

Silver nanoparticles (AgNPs) have attracted attention due to their unique properties and potential application. This research aimed to do green synthesis of AgNPs with Syzygium aromaticum leaves extract (SALE) and evaluate their antibacterial and antioxidant activities. Syzygium aromaticum leaves were extracted using distilled water at 70 °C for 30 min and the results were characterized with FTIR. AgNPs were synthesized by mixing AgNO3 precursor with SALE. The effects of parameters such as volume ratio of AgNO3 precursor to SALE, AgNO3 concentrations, and synthesis times were investigated. The synthesized AgNPs were characterized using UV-Vis spectrophotometer, FTIR, and TEM. Antibacterial activity of SALE and AgNPs was investigated against Escherichia coli (E.coli) and Bacillus subtilis (B. subtilis) with disc diffusion method and antioxidant activity was tested with DPPH method. The FTIR characterization revealed that SALE and resulting AgNPs contain O-H, C-H, C=O, C=C, C-O, and C≡C functional groups. The UV-Vis characterization demonstrated that AgNPs exhibited an absorption peak at λ = 420 nm indicating surface plasmon resonance. The optimal volume ratio of AgNO3 to SALE, AgNO3 concentrations, and synthesis time for AgNPs synthesis was achieved at 10:3, 5 mM, and 60 min respectively. TEM characterization indicated that AgNPs have spherical form and sizes ranging from 14 to 32 nm. The antibacterial testing revealed that AgNPs have antibacterial activities against E. coli and B. subtilis with inhibition zone values are 8,38 ± 0,48 and 6,88 ± 1,47 respectively. Additionally, antioxidant testing presented that the IC50 values were 85.05 µg/mL for SALE and 34.71 µg/mL for AgNPs. The results indicate that green synthesis of AgNPs from AgNO3 precursor with SALE was done successfully and this nanoparticle has good antibacterial and antioxidant activities.

Surface Modifications of Silver Nanoparticles with Chitosan, Polyethylene Glycol, Polyvinyl Alcohol, and Polyvinylpyrrolidone as Antibacterial Agents against Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica.

In medicine, the occurrence of antibiotic resistance was becoming a critical concern. At the same time, traditional synthesis methods of antibacterial agents often lead to environmental pollution due to the use of toxic chemicals. To address these problems, this study applies the green synthesis method to create a novel composite using a polymer blend (M8) consisting of chitosan (CS), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and silver nanoparticles. The results show that the highest ratio of AgNO3:M8 was 0.15 g/60 mL, which resulted in a 100% conversion of Ag+ to Ag0 after 10 h of reaction at 80 °C. Hence, using M8, Ag nanoparticles (AgNPs) were synthesized at the average size of 42.48 ± 10.77 nm. The AgNPs' composite (M8Ag) was used to inhibit the growth of Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA), and Salmonella enterica (SAL). At 6.25% dilution of M8Ag, the growth of these mentioned bacteria was inhibited. At the same dilution percentage of M8Ag, PA was killed.

Highly stable reinforced nanostructure of silver-decorated on graphene oxide phytosynthesized through central composite design for antibacterial activity: Green and eco-friendly method

In this study, the simultaneous effects of reaction time, reaction temperature, and ratio of AgNO3 and Curcuma longa extract on the nanoparticle size in the silver nanoparticles@graphene oxide (Ag@GO) nanocomposite were thoroughly investigated via the central composite design model (CCD). The obtained results showed that all parameters played a crucial role in the change in the AgNPs size. Indeed, the synthesis conditions were determined to be 31.9 min, 60.22 °C, and volume ratio between AgNO3 and extract of 0.96 (mL/mL) according to the simulated model, while these were determined at 32 min, 60 °C, and 1.0 (mL/mL) of AgNO3:extract volume ratio in empirical experiments. Under these conditions, the average particle size of the AgNPs was determined to be 22.19 nm, which showed a negligible deviation as compared to the experimental result (23.47 nm). Furthermore, the characterization of the Ag@GO was also assessed, in which the AgNPs affirmed the presence of spherical shapes evenly distributed on the GO sheets through XPS spectra, XRD pattern, TEM, and AFM images results. In addition, the as-prepared material also shows a great antibacterial performance against both Escherichia coli and Staphylococcus aureus strains with the IC50 values of 2.70 and 2.86 μg/mL at the bacteria density of 108 CFU/mL. Besides, the stability of the Ag@GO material in the form of suspension after 3 months was also evaluated, in which insignificant changes in the morphological structure were observed as compared to the initial sample. The aforementioned results exerted the great potential of the as-prepared material as an antibacterial agent in medicinal applications.

Bio-inspired synthesis of silver nanoparticles using Salsola imbricata and its application as antibacterial additive in glass ionomer cement

Nanotechnology has gained immense popularity and observed rapid development due to the remarkable physio-chemical properties of nanoparticles (NPs) and related nanomaterials. The green production of NPs has many benefits over traditional techniques because the current procedures are expensive, time-consuming, and involve harmful substances that limit their applicability. This study aimed to use a novel green source, the Salsola imbricata (SI) plant, which is commonly found in Central Asia and known for its medicinal properties as a reducing and stabilizing agent for the synthesis of AgNPs. The current study also utilized efficient statistical design, the Plackett–Burman Design (PBD) of Experiment method to synthesize the NPs. The characterization of NPs was carried out using UV-Vis spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM). The PBD results showed that only two out of four factors i.e. AgNO3 concentration and incubation time, were significant for the synthesis of SI-AgNPs. While remaining factors, incubation temperature and plant extract: AgNO3 ratio were non-significant. The SEM analysis result showed that SI-AgNPs had a size of 20–50 nm. The SI-AgNPs demonstrated strong antibacterial activity against oral pathogens such as S. mutans and Lactobacillus acidophilus, with the highest efficacy observed at a concentration of 2 mg ml−1. The addition of SI-AgNPs in glass ionomer cement significantly increased the antibacterial activity of GIC against S. mutans. Based on the results of the current study, the plant based AgNPs can be further evaluated in detail as alternate antimicrobial agent either alone or in combination with other antimicrobial agents for different dental applications.

Endophytic fungi-assisted biomass synthesis of eco-friendly formulated silver nanoparticles for enhanced antibacterial, antioxidant, and antidiabetic activities

Fungi-mediated biosynthesis of silver nanoparticles is one of the promising nanomanufacturing processes. Using endophytic fungi isolated from potential medicinal plants has emerged as a novel approach for producing several metal oxide nanoparticles in a green and cost-effective manner. The present study validates the biomimetic synthesis of silver nanoparticles of endophytic fungus (Phyllosticta capitalensis Henn.) (Phyllo-AgNPs) isolated from the leaves of Annona muricata and the effect of process variables, i.e., reductant concentration, ratio of AgNO3 to reductant concentration, reaction time and reaction pH to achieve maximum efficiency using the factorial design approach. The nanoparticle formation was confirmed by absorption peaks between 400 nm and 500 nm, followed by their characterization by UV–visible spectroscopy, TEM, SEM-EDX, XRD, particle size, and zeta potential analysis. The in-vitro antioxidant, antidiabetic and antimicrobial potential (agar well dfiffusion and minimum inhibitory concentration) of Phyllo-AgNPs at various concentrations were assessed. The Phyllo-AgNPs scavenged the 2,2-diphenyl-1-picrylhydrazyl radical and inhibited the activity of α-amylase and α-glucosidase enzymes at an IC50 of 31.75 ± 0.70, 39.32 ± 1.12 and 28.56 ± 1.08 μg/mL, respectively. The antimicrobial potential was determined against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli and, Salmonella typhimurium. The study revealed the therapeutic potential of Phyllo-AgNPs against pathogenic microorganisms. Additionally, the in-vitro antioxidant and antidiabetic activities showed improved results compared to the standard (ascorbic acid and acarbose). By taking note of this, Phyllo-AgNPs can be further studied for pre-clinical trials, which would be beneficial in developing novel medicines with no adverse effects for the benefit of mankind.

Green synthesis of silver nanoparticles using Phlebopus portentosus polysaccharide and their antioxidant, antidiabetic, anticancer, and antimicrobial activities

Silver nanoparticles (AgNPs) by green synthesis from fungi polysaccharides are attracting increasing attention owing to their distinctive features and special applications in numerous fields. In this study, a cost-effective and environmentally friendly biosynthesizing AgNPs method with no toxic chemicals involved from the fruiting body polysaccharide of Phlebopus portentosus (PPP) was established and optimized by single factor experiment and response surface methodology. The optimum synthesis conditions of polysaccharide-AgNPs (PPP-AgNPs) were identified to be the reaction time of 140 min, reaction temperature of 94 °C, and the PPP: AgNO3 ratio of 1:11.5. Formation of PPP-AgNPs was indicated by visual detection of colour change from yellowish to yellowish brown. PPP-AgNPs were characterized by different methods and further evaluated for biological activities. That the Ultraviolet-visible (UV–Vis.) spectroscopy displayed a sharp absorption peak at 420 nm confirmed the formation of AgNPs. Fourier transform infrared (FTIR) analysis detected the presence of various functional groups. The lattice indices of (111), (200), (220), and (331), which indicated a faced-centered-cubic of the Ag crystal structure of PPP-AgNPs, was confirmed by X-ray diffraction (XRD) and the particles were found to be spherical through high resolution transmission electron microscopy (HRTEM). Energy dispersive X-ray spectroscopy (EDS) determined the presence of silver in PPP-AgNPs. The percentage relative composition of elements was determined as silver (Ag) 82.5 % and oxygen (O) 17.5 % for PPP-AgNPs, and did not exhibit any nitrogen peaks. The specific surface area of PPP-AgNPs was calculated to be 0.5750 m2/g with an average pore size of 24.33 nm by BET analysis. The zeta potential was −4.32 mV, which confirmed the stability and an average particle size of 64.5 nm was calculated through dynamic light scattering (DLS). PPP-AgNPs exhibited significant free radical scavenging activity against DPPH with an IC50 value of 0.1082 mg/mL. The MIC values of PPP-AgNPs for E. coli, S. aureus, C. albicans, C. glabrata, and C. parapsilosis are 0.05 mg/mL. The IC50 value of the inhibition of PPP-AgNPs against α-glucosidase was 11.1 μg/mL, while the IC50 values of PPP-AgNPs against HepG2 and MDA-MB-231 cell lines were calculated to be 14.36 ± 0.43 μg/mL and 40.05 ± 2.71 μg/mL, respectively. According to the evaluation, it can be concluded that these green-synthesized and eco-friendly PPP-AgNPs are helpful to improve therapeutics because of significant antioxidant, antimicrobial, antidiabetic, and anticancer properties to provide new possibilities for clinic applications.

Valorization of Momordica charantia seeds into phytogenically synthesized silver nanoparticles for the protection of oyster mushrooms against Trichoderma pleuroticola

Green mold caused by Trichoderma pleuroticola is the most invasive disease of oyster mushrooms, causing massive losses worldwide. Herein, we valorized food waste, the Momordica seed extract (MSE), into silver nanoparticles (AgNPs-MSE). The synthesis parameters were optimized, and the biogenic AgNPs showed a remarkable antifungal activity against T. pleuroticola. Quantitative and qualitative analyses showed that the MSE was rich in bioactive compounds. The highly stable AgNPs-MSE was synthesized under the following conditions: MSE–AgNO3 ratio, 5:95; synthesis time, 9 min; temperature, 60 °C; and pH, 8.0. The UV absorption spectra showed surface plasma resonance peak at 428 nm, confirming the presence of spherical nanoparticles. FTIR spectra ascertained the involvement of phytoconstituents in the MSE during synthesis, and X-ray diffraction analysis revealed a face-centered cubic (fcc) crystalline structure with an average particle size of 11.34 nm. HR-TEM analysis corroborated the spherical shape, with a nanoparticle size of 8.0 nm. EDX analysis revealed the presence of silver, carbon, oxygen, nitrogen, sulfur, and chlorine in the AgNPs-MSE, which was further substantiated by XPS analysis. A zeta potential of − 29.7 mV and PDI of 0.144 revealed the good stability and uniformity of the synthesized AgNPs-MSE. The optimized AgNPs-MSE exhibited a potent antifungal activity against T. pleuroticola at 300 ppm in vitro. SEM and TEM analyses of AgNPs-MSE-treated T. pleuroticola showed hyphal system breakage and leakage of cytoplasmic contents that leads to cell death. Therefore, the use of the AgNPs-MSE as a nanoparticle-based fungicide has the potential to effectively control T. pleuroticola for oyster mushroom protection.

UV–vis Study on β‐Cyclodextrin as Dual Function for Synthesis AgNPs and Antibacterial Application

AbstractThe current study reveals the synthesis of silver nanoparticles (AgNPs) with β‐cyclodextrin (β‐CDs) as a dual function, reducing, and stabilizing agent. UV–vis study is carried out to monitor the optimum condition of AgNPs formation. It is observed that setting pH at 12, 1:33 concentration ratio of AgNO3 to β‐CDs, and 5 min of incubation time are the optimum condition to synthesize AgNPs. The stability of AgNPs 4 weeks after synthesized is confirmed by the UV–vis spectra. Fourier transform infrared (FTIR) characterization reveals there is a peak appearing assigned to C=O which proves a redox reaction occurs between AgNO3 and β‐CDs. Gram‐positive (Bacillus subtilis and Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli and Pseudomonas aeruginosa) are tested to investigate the antibacterial activity of AgNPs. This study shows that AgNPs exhibit inhibition of bacterial growth.

Silver chloride as sacrificial template to form silver chloride and gold-silver alloy hybrid nanocages for the reduction of 4-nitrophenol

Hollow cubic silver chloride and gold-silver alloy hybrid nanocages (AgCl-AuAg HNCs) were synthesized using silver chloride as a sacrificial template. AgCl nanostructures were readily synthesized by a mixture of silver nitrate (AgNO3) and sodium chloride (NaCl) solution. Chloroauric acid (HAuCl4) and ascorbic acid (AA) served as the gold precursor and reducing agent. Due to the capping and directing effect of Ag+ and Cl− ions, gold-silver alloy nanocages were formed. The particle size and surface plasmon resonance (SPR) peak of AgCl-AuAg HNCs can be tunable from 97 to 116 nm, and 600 nm to 740 nm with different molar ratio of AgNO3 and HAuCl4. The average particle size and shell thickness were 113.5 ± 19.6 nm and 14.2 ± 5.2 nm at molar ratio of 1:1.225, respectively. The synthesized AgCl-AuAg HNCs exhibited excellent catalytic properties and the apparent rate constant (Kapp) increased from 0.2046 min−1 to 1.8894 min−1 with increasing catalyst valume from 10 to 70 μL. The maximum turnover frequency (TOF) of the AgCl-AuAg HNCs reached up to 6.51 min −1 (390.6 h − 1) with 50 μL of AgCl-AuAg HNCs solution. It is expected that these AgCl-AuAg HNCs can be applied in water pollution control and environmental detection applications.

Incorporation of Ag NPs/palygorskite into chitosan/glycyrrhizic acid films as a potential antibacterial wound dressing

Chitosan/glycyrrhizic acid (CG) film has poor mechanical properties and antibacterial activity, which limits its practical application in wound dressing. In this study, Ag nanoparticles/palygorskite (Ag NPs/Pal) nanocomposites with different mass ratios were prepared by the metal salt pyrolysis and incorporated to synergistically improve the mechanical and antibacterial properties of CG films. The structural characteristics of CS/GA/Ag/Pal (CGAP) namocomposite films were characterized by SEM, ATR−FTIR and XRD. The effects of Ag NPs/Pal nanocomposites with different mass ratios on the physicochemical properties of the CGAP films were evaluated by systematic experiments. The CGAP nanocomposite films prepared by introducing Ag NPs/Pal nanocomposite with the mass ratio of AgNO3 to Pal of 0.5 had a uniform distribution of inorganic filler, good mechanical properties (tensile strength was 25.65 MPa and elongation at break was 63.71%) and excellent antibacterial activity (antibacterial effectiveness up to 100%), and preserved favorable swelling behavior (144.70%), acceptable light transmittance (T800 was 62.95%) and outstanding biocompatibility (hemolysis percentage was 1.69%). Overall, the above results demonstrate that the CGAP composite films are suitable for wound dressings in biomedical applications.

SERS detection of anthraquinone dyes: Using solvothermal silver colloid as the substrate

Anthraquinone dyes have been widely used to color textile fibers since antiquity. Identification of the dyes can help us understand the dyeing processes and when and where the textiles were produced. Herein, we present a strategy based on surface-enhanced Raman scattering (SERS) with a novel silver colloid substrate for the detection of anthraquinone dyes. Quasi-spherical silver particles with different sizes were prepared by the solvothermal method and then characterized by transmission electron microscopy (TEM). The silver colloid substrates exhibited high-density hot spots with good reproducibility (RSDs of 3 ∼ 16 %) and high sensitivity. Among them, Ag-C2 (the molar ratio of AgNO3 to PVP is 0.367, reacted for 2 h) was used to detect anthraquinone dyes in reference silk fibers as well as ancient textile samples due to the highest sensitivity and the low RSD (5.37 %) in this study. More importantly, Ag-C2 can be utilized to distinguish three madder species (Rubia tinctorum, Rubia cordifolia, and Rubia argyi) depending on the SERS intensity of alizarin and purpurin.

In Situ Green Synthesis of Graphene Oxide-Silver Nanoparticles Composite with Using Gallic Acid.

The adoption of plant-derived natural products to synthesize metal nanoparticles and their complexes has the advantages of mild reaction conditions, environmental protection, sustainability and simple operation compared with traditional physical or chemical synthesis methods. Herein, silver nanoparticles (AgNPs) were in situ synthesized on the surface of graphene oxide (GO) by a “one-pot reaction” to prepare graphene oxide-silver nanoparticles composite (GO-AgNPs) based on using AgNO3 as the precursor of AgNPs and gallic acid (GA) as the reducing agent and stabilizer. The size and morphology of GO-AgNPs were characterized by ultraviolet-visible spectrophotometer (Uv-vis), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), X-ray diffractometer (XRD) and dynamic light scattering (DLS). The effects of pH, temperature, time and material ratio on the synthesis of GO-AgNPs were investigated experimentally. The results showed that ideal GO-AgNPs could be prepared under the conditions of pH = 9, 45°C, 2 h and the 2:1 of molar ratio of AgNO3 to GA. The AgNPs within GO-AgNPs are highly crystalline spherical particles with moderate density on the surface of GO, and the size of AgNPs is relatively uniform and determined to be about 8.19 ± 4.21 nm. The research results will provide new ideas and references for the green synthesis of metal nanoparticles and their complexes using plant-derived natural products as the reducing agent and stabilizer.

Optimization and Characterization of Biogenic Silver Nanoparticles Synthesized by Leaves Extract of Alphonsea madraspatana

Background: Literature evidence as well as traditional uses of genus Alphonsea reveal significant antimicrobial and anti-oxidant activitiesencouraging to consider A. madraspatana to have potent antimicrobials, there by offering potential adjuncts to synthesize improved antimicrobial Silver nanoparticles (AgNPs). The objective of the present exposition is to optimize reaction parameters to synthesize antimicrobial Biogenic Silver nanoparticles (BAgNPs) from the extract of A. madraspatana leaves (AML) and to evaluate the effect against bacteria. Methods: BAgNPs were synthesized by the optimized reaction. The Synthesized nanoparticles were characterized by UV, IR, ICP-MS and XRD analysis. The antibacterial potency of optimized BAgNPs was evaluated against E. coli by comparing with positive controls. Results: Results of the optimization process indicate nanoscale BAgNPs were produced at 45°C for 120 min at pH 8 with 1:5 volume ratio of AgNO3 and extract. Optimized BAgNPs exhibits relatively higher antimicrobial activity (31±1mm) compared to Ciprofloxacin (27±1mm) and marketed nanosilver (28± 2 mm). The developed BAgNPs show comparable biofilm inhibition (86.50%) as compared to marketed nanosilver (88.10%) and Ciprofloxacin (83.10%). Conclusion: Experimental evidence suggests methanolic extract of AML under predefined conditions, which successfully generate nano-template of silver with better antibacterial response against E. coli.

Photoassisted Synthesis of Silver Nanoparticles Using Riceberry Rice Extract and Their Antibacterial Application

The green synthesis of silver nanoparticles (AgNPs) has been attractive in biomedical applications due to its nontoxic and eco-friendly approach. This study presents the facile, rapid, and cost-effective synthesis of AgNPs by photoassisted chemical reduction using Riceberry (RB) rice extract as a reducing agent. The effects of reaction parameters including photoirradiation, irradiation time, the volume ratio of silver nitrate (AgNO3) to RB extract, and pH condition on the AgNP formation were also investigated. The characterization of AgNPs was determined by UV–visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy. For antibacterial application, the synthesized AgNPs were studied by disc diffusion method against Escherichia coli and Staphylococcus aureus. The results indicated that light irradiation was an important factor to accelerate the formation of AgNPs. The synthesis parameters including volume of RB extract and pH condition significantly affected the particle size and crystallinity of AgNPs. The volume ratio of AgNO3 to RB extract 1 : 12.5 at pH 2.5 under photoirradiation was the successful condition to form nanometer-sized crystalline particles (average particle size of 59.48 ± 0.37 nm ) within 30 min with a rate constant of 0.210 min–1. The FT-IR measurement also suggested that the phytochemical constituents in RB extract were served as reducing and stabilizing agents for the synthesis of AgNPs. Additionally, the obtained AgNPs from various conditions demonstrated the antibacterial activity against both strains. Therefore, this study proposes an effective integration technique to synthesize AgNPs within a short time for antibacterial application.

Mechanochemistry as an Alternative Method of Green Synthesis of Silver Nanoparticles with Antibacterial Activity: A Comparative Study.

This study shows mechanochemical synthesis as an alternative method to the traditional green synthesis of silver nanoparticles in a comparative manner by comparing the products obtained using both methodologies and different characterization methods. As a silver precursor, the most commonly used silver nitrate was applied and the easily accessible lavender (Lavandula angustofolia L.) plant was used as a reducing agent. Both syntheses were performed using 7 different lavender:AgNO3 mass ratios. The synthesis time was limited to 8 and 15 min in the case of green and mechanochemical synthesis, respectively, although a significant amount of unreacted silver nitrate was detected in both crude reaction mixtures at low lavender:AgNO3 ratios. This finding is of particular interest mainly for green synthesis, as the potential presence of silver nitrate in the produced nanosuspension is often overlooked. Unreacted AgNO3 has been removed from the mechanochemically synthesized samples by washing. The nanocrystalline character of the products has been confirmed by both X-ray diffraction (Rietveld refinement) and transmission electron microscopy. The latter has shown bimodal size distribution with larger particles in tens of nanometers and the smaller ones below 10 nm in size. In the case of green synthesis, the used lavender:AgNO3 ratio was found to have a decisive role on the crystallite size. Silver chloride has been detected as a side-product, mainly at high lavender:AgNO3 ratios. Both products have shown a strong antibacterial activity, being higher in the case of green synthesis, but this can be ascribed to the presence of unreacted AgNO3. Thus, one-step mechanochemical synthesis (without the need to prepare extract and performing the synthesis as separate steps) can be applied as a sustainable alternative to the traditional green synthesis of Ag nanoparticles using plants.

Characteristic of silver nanowires prepared by polyol method based on orthogonal experimental design

In this study, silver nanowires (AgNWs) were prepared by the polyol method using silver nitrate (AgNO3) as the silver source and polyvinylpyrrolidone (PVP) as the structure-directing agent under different reaction conditions. In order to obtain AgNWs with good uniformity and electrical conductivity, the orthogonal experiment method was adopted to design an experimental scheme. The scanning electron microscope, energy-dispersive X-ray spectrometer, X-ray diffraction, UV-2550 UV–Visible spectrophotometer, transmission electron microscope, Fourier transform infrared and Raman spectra were combined to characterize synthesized AgNWs. It can be concluded from experimental data that when the reaction temperature is 150°C, the ratio of AgNO3 to PVP is 1:3, the drop rate of PVP is 65 ml h–1, with the existence of ferric chloride (FeCl3), and the AgNWs exhibit optimal morphology with the diameter ranging from 60 to 200 nm. The results in this study will provide experimental guide for controllable formation of AgNWs.

Facile green synthesis of Ag/AgCl nanoparticles derived from Chara algae extract and evaluating their antibacterial activity and synergistic effect with antibiotics

Here, we present a pathway for the green synthesis of Ag/AgCl nanoparticles derived from freshwater Chara vulgaris algae. The formation of Ag/AgCl NPs is confirmed by XRD, UV–Vis spectroscopy, and SEM techniques. The volume with an aqueous extract of Chara vulgaris: AgNO3 ratio 3:1 possessed optimal synthesised Ag/AgCl NPs. A plasmon absorbance peak, at 395 nm was observed in the UV–vis spectrum. XRD patterns confirmed the highly crystalline FCC structure of Ag/AgCl NPs. SEM imaging of Ag/AgCl NPs indicated nanoparticles of size 16.99 ± 0.3 nm. The antibacterial activity of Ag/AgCl NPs was evaluated against Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa. Combining Ag/AgCl NPs with antibiotics causes growth inhibition of both Gram-positive and Gram-negative bacteria. The fractional inhibitory concentration index (FICI) is used to evaluate the synergistic antimicrobial effect of combining nanoparticles with antibiotics. The combinations of Ag/AgCl NPs with Gentamicin, Erythromycin and Vancomycin show a partial synergistic activity against E. coli, K. pneumoniae and P. aeruginosa, respectively. The combination of Ag/AgCl NPs with antibiotics could potentially prohibit the development of resistant bacteria against antibiotics.

Preparation of micron–sized polystyrene/silver core–shell microspheres by ultrasonic assisted electroless plating

In the study, PS/Ag composite microspheres with polystyrene (PS) core and silver shell were synthesized by ultrasonic electroless plating. The samples were characterized by SEM, FTIR and XRD. The effects of times of sensitization and silver plating, mass ratio of AgNO3 to PS microspheres and stirring method on the preparation and dispersion of PS/Ag microspheres were studied. The results show that the more times of sensitization and silver plating, the more uniform the silver deposition on the surface of microspheres. When the mass ratio of AgNO3 to PS microspheres is 2: 1, it can promote the uniform coating of silver shell and reduce the content of free silver. Ultrasonic assisted electroless plating for 10 min can prevent PS/Ag microspheres from agglomerating and improve the speed of electroless plating. The thickness of the silver shell on the surface of the PS microsphere is about 200 nm.

A one-step synthesis of ultra-long silver nanowires with ultra-high aspect ratio above 2000 and its application in flexible transparent conductive electrodes

Silver nanowires (AgNWs), appear as an extremely promising candidate for the next generation of flexible transparent conductive electrodes (FTCEs). However, the performance of AgNWs-FTCEs was severely limited by the aspect ratio of AgNWs, while it was still a big challenge to fabricate AgNWs with high aspect ratio nowadays. To improve the aspect ratio of AgNWs, bromide ion (Br−), cupric ion (Cu2+) and polyvinylpyrrolidone (PVP, Mw ≈ 1300 000) which are beneficial for the synthesis of high aspect ratio AgNWs, were introduced in this article. The high quality and uniform AgNWs with the average diameter of 77.6 nm and the aspect ratio above 2000 were fabricated via a one-step solvothermal method. The effects of reaction time, molar ratio of AgNO3 to PVP and the concentration of CuBr2 on the aspect ratio of AgNWs were discussed. The mechanism of the synthesis of high aspect ratio AgNWs was explored. After that, the prepared AgNWs were spin-coated on the surface of PET film, the FTCEs based on the ultra-high aspect ratio AgNWs without any post-treatments exhibits relatively high transmittance, low haze and low sheet resistance, and the AgNWs have little effect on the optical performance of pristine PET film. The outstanding performance of the prepared FTCEs indicated that the ultra-high aspect ratio AgNWs are ideal materials in the application of FTCEs, and the method of fabricating AgNWs could provide a direction to the high aspect ratio AgNWs.

PVP‐mediated galvanic replacement growth of AgNPs on copper foil for SERS sensing

Herein, the authors present a simple and cost-effective silver nanoparticles (AgNPs)-based surface-enhanced Raman scattering (SERS) sensor based on galvanic displacement reaction using AgNO3 and copper foil as precursors. With the mediation of polyvinyl pyrrolidone (PVP), AgNPs grow in-situ on the surface of copper foil at room temperature. AgNPs-based SERS sensor was prepared with optimised AgNO3 concentration of 50 mM, the mass ratio of AgNO3 to PVP of 2:1 and characterised using scanning electron microscopy and X-ray diffraction. As-fabricated SERS sensor exhibited a high Raman signal enhancement factor of 3.5 × 105 in the detection of Rhodamine 6G (R6G). Furthermore, a decent linear relationship for methyl parathion sensing was obtained in the range from 1 × 10−6 to 1 × 10−4 M, with an actual detection limit of 1 × 10−6 M. Recoveries of methyl parathion-spiked lake water samples ranging from 93.64 to 106.16% were obtained, suggesting the feasibility of the SERS sensor. These features demonstrated that the AgNPs-based SERS sensor can potentially be used in sensing a trace amount of chemicals in surface water for environmental protection.