Commercial AgNPs Research Articles

Antibiofilm effect of green engineered silver nanoparticles fabricated from Artemisia scoporia extract on the expression of icaA and icaR genes against multidrug-resistant Staphylococcus aureus.

Silver nanoparticles (AgNPs) are at the forefront of the swiftly developing scope of nanotechnology. In the current study, we investigated the green synthesis of AgNPs using Artemisia scoporia as a reducing and capping agent. The biosynthesized AgNPs were characterized using ultraviolet-visible spectroscopy, X-ray diffraction, Fourier-Transform infrared spectroscopy, dispersive absorption spectroscopy, scanning electron microscopy, and transmission electron microscopy. The efficacy of the nanoparticle synthesis was assessed by comparing the antibiofilm activity with commercial AgNPs. The effect of sub-minimum inhibitory concentrations (MICs) of AgNPs on biofilm formation was determined by microtiter plate assay. The expression level of the icaA and icaR genes was assessed by real-time polymerase chain reaction assay. The structural and functional aspects of AgNPs were confirmed. The expression levels of icaA and icaR in the isolates exposed to sub-MIC of both commercial and biosynthetic AgNPs were lower and higher than in the control group, respectively. Our results also indicated that greater reduction and induction in icaA and icaR gene expression were noticed with the sub-MIC doses of biosynthetic AgNP versus commercial AgNP, respectively. This study suggested the application of AgNPs as a significant therapeutic and clinical option in the future and usage for fabricating medical implants. Nevertheless, further investigation is required for examining the pharmaceutical and medicinal properties of AgNPs.

Comparative study of nutritional and economical parameters of silkworm (Bombyx mori) treated with silver nanoparticles and Spirulina

BackgroundSericulture depends on rearing of silkworm on mulberry leaves. For this reason, Silk production has direct relationship with larval growth. One of the alternative ways of improvement of larval growth and cocoon production is enrichment of mulberry leaves with supplementary nutrients. The present study has been aiming to find out the feed efficacy of silver nanoparticles (AgNPs) and Spirulina-treated MR2 mulberry leaves with regard to food utilization by larvae and ultimate impact on the economic parameters of silkworm (Bombyx mori).ResultFresh mulberry leaves were treated with chemically mediated AgNPs and Spirulina; it was diluted by different concentrations such as 100 ppm AgNPs (T2), 300 ppm AgNPs (T3), 500 ppm AgNPs (T4), AgNPs with Spirulina (T5), and Spirulina alone (T6). Group T1 served as the control. The result indicates significant differences among the six groups. The economic traits and the nutrient efficacy were significantly increased in AgNPs and Spirulina-treated groups when compared to those in the control.ConclusionSilkworms are the only source for producing silk. Commercial AgNPs and Spirulina administration has significantly induce food consumption, utilization, and superior cocoon characters by maintaining a balance in the gut flora. Thus, it is inferred that silkworm larvae fed with commercial AgNPs and Spirulina beneficially influence the energy and economic parameters of B. mori, which can be exploited in commercial cocoon production.

Inkjet Printed Interdigitated Biosensor for Easy and Rapid Detection of Bacteriophage Contamination: A Preliminary Study for Milk Processing Control Applications

Bacteriophages are responsible for significant material and time losses in the dairy industry. This because these viruses infect the selected lactic starter cultures used for milk fermentation, i.e., the first stage toward cheese production. Standard detection techniques are time- and labor-consuming, causing huge costs related to production plant sanitation and product wasting. A new type of biosensor for early detection of bacteriophage contamination is highly demanded by the milk processing market, and inkjet-printed electrochemical sensors could be the answer. Inkjet printing is a well-known technology that has been revisited in recent years, using silver nanoparticle (AgNP) based inks for low-cost and easy fabrication of sensing and biosensing systems on flexible and eco-compatible substrates. In this research, we studied inkjet printing for the manufacturing of both interdigitated electrodes arrays (IDEAs), and a versatile system to monitor bacterial cultures by electrochemical impedance spectroscopy (EIS). In particular, we studied this biosensing system for the detection of bacteriophages by comparing its performance with standard microbiological methods. We performed electrical and morphological characterizations of the devices produced with a consumer-use inkjet printer with commercial AgNPs ink on flexible substrates, such as office paper, polyethylene (PET), and photo paper. We used light microscopy optical analysis, profilometry, atomic force microscopy (AFM), and scanning electron microscopy (SEM) imaging to define the objects resolution, their real dimensions, and thickness. We also investigated the devices’ conductivity and layout, by EIS measurements with a standard buffer solution, i.e., phosphate buffered saline (PBS). Finally, we tested our system by monitoring Lactococcus lactis cultures and bacteriophage infection. We compared the results to those obtained by two standard microbiological methods in terms of response time, proving that our technique requires less than half the time of other methods and no specialized personnel.

Wheat straw extracted lignin in silver nanoparticles synthesis: Expanding its prophecy towards antineoplastic potency and hydrogen peroxide sensing ability.

Lignin, is the most abundant, renewable and degradable biopolymer available in the nature. The present study exploited purified lignin from wheat straw as reducing, capping and stabilizing agent for the green synthesis of silver nanoparticles (Li-AgNPs) under optimized conditions. The analytical studies revealed synthesized Li-AgNPs having a face centered cubic crystalline structure, size ranging ~15-20 nm and the biomolecules comprising majorly phenolic, hydroxyl and carboxylic group of lignin coated on the surface of AgNPs. Li-AgNPs showed significant antimicrobial efficacy against human pathogens namely; Staphylococcus aureus and Escherichia coli and also determined their minimum inhibitory and minimum bactericidal concentration (MIC and MBC). Li-AgNPs also displayed substantial antioxidant activity in terms of well-known enzyme marker viz.; ABTS and DPPH free radical scavenging assay relative to commercial AgNPs. In vitro cytotoxicity assay of Li-AgNPs demonstrated dose-dependent toxicity effects in SKOV3 ovarian cancer cell line (LD50; 150 μg/mL) indicative of promising anticancer agent. Further, H2O2 sensing ability of stabilized Li-AgNPs exhibited its vital role in determining reactive oxygen species. Synthesis of Li-AgNPs is a cheap green technology and could exhibit its commercial use in biomedical, cosmetic, and pharmaceutical industry.

Comparison between various concentrations of commercial and synthesized silver nanoparticles on biochemical parameters and growth of Stevia rebaudiana B.

Nanoparticles are particles between 1 and 100 nm in size that has the ability to modify their physio-chemical properties compared to other material. In the present study, leaves of Stevia rebaudiana B. were used to extracts to synthesize Ag nanoparticles from AgNO3 (1 mM concentration) and then studied the effects of these commercial and synthesized Ag nanoparticles on biochemical (chlorophyll content, anthocyanin, flavonoid, carbohydrate, protein and DPPH) and growth characteristics of Stevia at different concentrations (0, 10, 20, 40 mM). UV–visible spectroscopy was used to identify the formation of Ag and analyzed synthesized Ag nanoparticles at 300–700 nm. Absorption maxima at 435 nm wavelength confirmed their synthesis. Examining synthesized AgNPs from S. rebaudiana extract using SEM micrograph showed a 25 nm dimension and spherical shape. Application of synthesized and commercial AgNPs at various concentrations on Stevia showed a dependency on concentrations that at 10 and 20 mM of AgNP, an increase in leaf area, shoot height and dry and fresh weight was recorded. At the biochemical level, applying 40 mM of synthesized AgNP resulted in increased chlorophyll content which led to accumulation of biomass besides soluble anthocyanin, flavonoid and carbohydrate and also total protein and DPPH, compared to plants treated with commercial AgNP. Moreover, the results demonstrated that increasing AgNP concentration enhances glycoside content in both treatments. Based on our findings, synthesized AgNP is more effective in accelerating the growth and improve the quality of natural product in Stevia plants than commercial AgNP.

Investigation on some main glycosides content of Stevia rebaudian B. under different concentrations of commercial and synthesized silver nanoparticles

Stevia rebaudiana B. extract as a low-calorie sweetener has gained worldwide approval. Synthesized nanoparticles by plant have been used in different programs such as medical, pharmaceutical and agricultural fields. Here, we report the increase of the main glycosides of stevia plant with silver nanoparticles (AgNPs) treatment. This fact has stimulated research on the analysis and comparison of different concentrations of commercial and synthesized AgNPs on the glycosides of stevia plant by highperformance liquid chromatography (HPLC). After AgNPs synthesis, spectrum absorption of extracts was analyzed in different ranges from 300 to 700 nm and the maximum peak was observed at 420 nm. Transmission electron microscopy (TEM) micrograph of synthesized AgNPs from Stevia rebaudiana extract showed spherical shape with the size of 25 nm. A comparison between quantities of glycoside by HPLC under both treatments of AgNP exhibited that synthesized AgNPs were more effective than commercial AgNPs on stevioside and then rebaudioside. On the other hand, results showed that increasing AgNP concentration in both treatments will lead to glycoside content enhancement. Overall, significant changes were observed in the glycosides in plants under synthesized and commercial AgNP treatment that could be used to create plants with higher quality of glycosides for pharmaceutical approaches.

Physiological, ultrastructural and proteomic responses of tobacco seedlings exposed to silver nanoparticles and silver nitrate

Since silver nanoparticles (AgNPs) are a dominant nanomaterial in consumer products, there is growing concern about their impact on the environment. Although numerous studies on the effects of AgNPs on living organisms have been conducted, the interaction of AgNPs with plants has not been fully clarified. To reveal the plant mechanisms activated after exposure to AgNPs and to differentiate between effects specific to nanoparticles and ionic silver, we investigated the physiological, ultrastructural and proteomic changes in seedlings of tobacco (Nicotiana tabacum) exposed to commercial AgNPs and ionic silver (AgNO3) from the seed stage. A higher Ag content was measured in seedlings exposed to AgNPs than in those exposed to the same concentration of AgNO3. However, the results on oxidative stress parameters obtained revealed that, in general, higher toxicity was recorded in AgNO3-treated seedlings than in those exposed to nanosilver. Ultrastructural analysis of root cells confirmed the presence of silver in the form of nanoparticles, which may explain the lower toxicity of AgNPs. However, the ultrastructural changes of chloroplasts as well as proteomic study showed that both AgNPs and AgNO3 can affect photosynthesis. Moreover, the majority of the proteins involved in the primary metabolism were up-regulated after both types of treatments, indicating that enhanced energy production, which can be used to reinforce defensive mechanisms, enables plants to cope with silver-induced toxicity.

Biosynthesis of silver nanoparticles in collagen gel improves their medical use in periodontitis treatment

ABSTRACTSilver nanoparticles (AgNP) suspensions were biosynthesized by silver ions reduction in the presence of collagen, a nontoxic, organic polymer, intending to improve their medical use in periodontitis treatment. Spectrophotometric measurements showed a time- and concentration-dependent increase of AgNP formation in each suspension variant. Transmission electron microscopy revealed spherical morphology of AgNP in collagen and their mean diameter size was around 30 nm. The particle size distribution and zeta potential values of AgNP in collagen were determined by dynamic light scattering measurements. The surface charge of AgNP in collagen was positive, while commercial AgNP stabilized in citrate had negative surface charge. In vitro cytotoxicity testing of AgNP in collagen showed that they were biocompatible with human gingival fibroblasts in a wider range of concentrations than commercial nanoparticles. The antibacterial activity of AgNP in collagen against two pathogenic strains present in the periodontal pocket was dose-dependent and higher than that of AgNP in citrate. All these results demonstrated that AgNP prepared in collagen gel had improved properties, like small diameter, positive surface charge, high biocompatibility in human gingival fibroblasts, efficiency against bacterial growth and, thus, better therapeutic potential in periodontal disease treatment.

Brassica rapa var. japonica Leaf Extract Mediated Green Synthesis of Crystalline Silver Nanoparticles and Evaluation of Their Stability, Cytotoxicity and Antibacterial Activity

Silver nanoparticles (AgNPs) were successfully synthesized from the reduction of Ag+ using AgNO3 solution as a precursor and Brassica rapa var. japonica leaf extract as a reducing and capping agent. This study was aimed at synthesis of AgNPs, exhibiting less toxicity with high antibacterial activity. The characterization of AgNPs was carried out using UV–Vis spectrometry, energy dispersive X-ray spectrometry, fourier transform infrared spectrometry, field emission scanning electron microscopy, X-ray diffraction, atomic absorption spectrometry, and transmission electron microscopy analyses. The analyses data revealed the successful synthesis of nano-crystalline Ag possessing more stability than commercial AgNPs. The cytotoxicity of Brassica AgNPs was compared with commercial AgNPs using in vitro PC12 cell model. Commercial AgNPs reduced cell viability to 23% (control 97%) and increased lactate dehydrogenase activity at a concentration of 3 ppm, whereas, Brassica AgNPs did not show any effects on both of the cytotoxicity parameters up to a concentration level of 10 ppm in PC12 cells. Moreover, Brassica AgNPs exhibited antibacterial activity in terms of zone of inhibition against E. coli (11.1 ± 0.5 mm) and Enterobacter sp. (15 ± 0.5 mm) which was higher than some previously reported green-synthesised AgNPs. Thus, this finding can be a matter of interest for the production and safe use of green-AgNPs in consumer products.

Bio-fabrication of silver nanoparticles using the leaf extract of an ancient herbal medicine, dandelion (Taraxacum officinale), evaluation of their antioxidant, anticancer potential, and antimicrobial activity against phytopathogens.

In recent years, the use of nanoparticle-based antimicrobials has been increased due to many advantages over conventional agrochemicals. This study investigates the utilization of common medicinal plant dandelion, Taraxacum officinale, for the synthesis of silver nanoparticles (TOL-AgNPs). AgNPs were evaluated for antimicrobial activity against two important phytopathogens, Xanthomonas axonopodis and Pseudomonas syringae. The morphology, size, and structure of TOL-AgNPs were characterized using UV-visible spectroscopy and X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FT-IR) showed the presence of phytochemicals involved during synthesis of NPs. High-resolution transmission electron microscopy (HR-TEM) analysis shed light on the size of monodispersed spherical AgNPs ranging between 5 and 30nm, with an average particle size of about 15nm. The TOL-AgNPs (at 20μg/mL concentration) showed significant antibacterial activity with significant growth inhibition of phytopathogens X. axonopodis (22.0±0.84mm) and P. syringae (19.5±0.66mm). The synthesized AgNPs had higher antibacterial activity in comparison with commercial AgNPs. Synergistic assays with standard antibiotics revealed that nanoformulations with tetracycline showed better broad-spectrum efficiency to control phytopathogens. They also possessed significant antioxidant potential in terms of ABTS (IC50=45.6μg/mL), DPPH (IC50=56.1μg/mL), and NO (IC50=55.2μg/mL) free radical scavenging activity. The TOL-AgNPs showed high cytotoxic effect against human liver cancer cells (HepG2). Overall, dandelion-mediated AgNPs synthesis can represent a novel approach to develop effective antimicrobial and anticancer drugs with a cheap and eco-friendly nature.

Nature Inspired Green Fabrication Technology for Silver Nanoparticles

Background: Silver nanofabricated products are well known elements from ages, and have great demand at present due to their massive significance in therapeutics, diagnostics, theranostics and targeted drug delivery systems. Silver nanoparticles (AgNPs) came into limelight, owing to their diverse pharmacotherapeutic potentials such as antiproliferative, anti-infective, anti-inflammatory, anti-coagulant etc. This resulted in increased commercial production of AgNPs and Ag-related products at highest pace. In majority of commercial AgNP production, traditionally wet chemical reduction techniques are employed that utilize chemicals that are non-ecofriendly, produce by-products, emit harmful substances and are expensive. Plant extracts are most environment friendly, easily available and are economically viable. The biological mediated approach serves as the most promising alternative to synthesize size-controlled AgNPs commercially. Keywords: Extract, green synthesis, nanomedicine, nanoparticles, patents, silver.

Biosíntesis de nanopartículas de plata por extractos de hoja de Plectranthus amboinicus y su actividad catalítica hacia la degradación de azul de metileno

Synthesis of nano-material with the controlled size and shape is the prime concern of research in nanotechnology. In this study, the synthesis of silver nanoparticles (Ag NPs) were carried out using Plectranthus amboinicus leaf extract as reducing agent. The synthesized Ag NPs was characterized by using X-ray diraction, scanning electron microscope, Fourier transform infrared spectroscopy and UV-vis spectroscopy. We further investigated the catalytic property of the biosynthesized Ag NPs by degradation of methylene blue (MB) in the presence of sodium borohydride. Compared with commercial Ag NPs, the proposed Plectranthus amboinicus leaf extract-deduced Ag NPs exhibited a much higher catalytic performance due to the well dispersibility caused by the attachment of biomolecules on the Ag NPs surface.

Antioxidant and catalytic applications of silver nanoparticles using Dimocarpus longan seed extract as a reducing and stabilizing agent

In this study, a simple and environmental friendly method was developed for the synthesis of silver nanoparticles (Ag-NPs) using Dimocarpus longan seed extract as a source of reducing and stabilizing agent. The appearance of a surface plasmon resonance peak at 432nm confirmed the synthesis of silver nanoparticles (UV–visible spectroscopy). The biosynthesized Ag-NPs were face centered cubic structures (XRD) with an approximate particle size of 40nm (TEM). Optimization study revealed that 10mL of plant extract (2mM AgNO3) at 180min of incubation resulted the optimum product synthesis. Poly-phenolic compounds were majorly involved in the reduction of silver ions into Ag-NPs (FT-IR). The catalytic activities of Ag-NPs were assessed against the photo-catalytic degradation of methylene blue and chemo catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The results indicated that the prepared Ag-NPs have strong chemo catalytic activity with a complete reduction of 4-NP to 4-AP within 10min. Similarly, Ag-NPs displayed higher photo-catalytic activity (K=0.12) as compared to commercial Ag-NPs (K=0.003). In addition, the silver nanoparticles exhibited a promising antioxidant activity in scavenging DPPH radicals. The findings of this study conclude that the biosynthesized Ag-NPs are promising agent possessing strong catalytic and reducing properties.

Comparison of the Physical Characteristics of Green-Synthesized and Commercial Silver Nanoparticles: Evaluation of Antimicrobial and Cytotoxic Effects

We investigated a novel green route synthesis of silver nanoparticles (AgNPs) using watermelon rind powder extract (WR-AgNPs) as a reducing and capping agent. The efficiency of nanoparticle synthesis was evaluated by comparing the structure, functional groups, antibacterial activity, and cytotoxic effects with commercial AgNPs (C-AgNPs). The AgNP production was initially confirmed based on color changes and wavelength scanning by ultraviolet–visible spectra, which exhibited a surface plasmon resonance peak at 450 nm. We used energy-dispersive spectroscopy to confirm silver and sample purity of both experimental and commercial AgNPs from 2 to 4 keV. Fourier transform infrared spectroscopy analysis showed that the AgNPs were reduced and capped with biomolecules from functional groups in the watermelon powder extract. Further, the analysis showed that the synthesized AgNPs were similar to C-AgNPs. The morphology and crystalline nature of both AgNPs were determined using high-resolution transmission electron microscopy and X-ray powder diffraction. In addition, the synthesized and commercial AgNPs were subjected to antibacterial and cytotoxicity assays. Three-way ANOVA indicated that treatments for WR-AgNPs or C-AgNPs as well as concentration and time had significant effects on Brevibacterium linens and Staphylococcus epidermidis—an odor-causing bacteria. With respect to cytotoxic effects, 67 % cell death was observed with high concentrations (10 mg/L) of both AgNPs.

Nanocrystalline Cellulose-Assisted Generation of Silver Nanoparticles for Nonenzymatic Glucose Detection and Antibacterial Agent.

Nanocrystalline cellulose (NCC) is a kind of natural biopolymers with merits of large surface area, high specific strength and unique optical properties. This report shows that NCC can serve as the substrate, allowing glucose to reduce Tollen's reagent to produce silver nanoparticles (AgNPs) at room temperature. The generation of AgNPs is affected by the factors such as the concentrations of silver ions, NCC and glucose, as well as the different reaction temperatures. The AgNPs with NCC are applied for the development of a visual, quantitative, nonenzymatic and high-sensitive assay for glucose detection in serum. This assay is also used for monitoring the concentration change of glucose in medium during cell culture. For the antibacterial activity, the minimal inhibitory concentration (MIC) of the generated AgNPs with NCC is much lower than that of commercial AgNPs, attributed to the good dispersion of AgNPs with the presence of NCC. As NCC exhibits unique advantages including green, stable, inexpensive, and abundant, the NCC-based generation of AgNPs may find promising applications in clinical diagnosis, environmental monitoring, and the control of bacteria.

Sonochemically-Produced Metal-Containing Polydopamine Nanoparticles and Their Antibacterial and Antibiofilm Activity.

A facile one-pot sonochemical synthesis of Cu-, Ag-, and hybrid Cu/Ag-based polydopamine nanoparticles (Cu-, Ag-, and Cu/Ag-PDA-NPs) and the mechanisms by which they exert antibacterial and antibiofilm activities are reported. We showed that the nanoparticles are spherical with a core-shell structure. Whereas Cu is chelated to the shell of Cu-PDA-NPs in oxidation states of +1/+2, the core of Ag-PDA-NPs is filled with elemental Ag°. Sonochemical irradiation of dopamine in the presence of both Cu(2+) and Ag(+) generates hybrid Cu/Ag-PDA-NPs, whose shells are composed of Cu-chelated PDA with Ag° in the core. The redox potential of the metals was found to be the main determinant of the location and oxidation state of the metals. Leaching studies under physiological conditions reveal a relatively fast release of Cu ions from the shell, whereas Ag leaches very slowly from the core. The metal-containing PDA-NPs are highly microbicidal and exhibit potent antibiofilm activity. The combination of both metals in Cu/Ag-PDA-NPs is especially effective against bacteria and robust biofilms, owing to the dual bactericidal mechanisms of the metals. Most importantly, both Ag- and Cu/Ag-PDA-NPs proved to be significantly more antibacterial than commercial Ag-NPs while exhibiting lower toxicity toward NIH 3T3 mouse embryonic fibroblasts. Mechanistically, the metal-containing PDA-NPs generate stable PDA-semiquinone and reactive oxygen species under physiological conditions, which contribute at least partly to the antimicrobial activity. We also demonstrated that simple treatment of surfaces with Ag-PDA-NPs converts them to antibacterial, the activity of which was preserved even after prolonged storage under ambient conditions.

Exposure of activated sludge to nanosilver and silver ion: Inhibitory effects and binding to the fractions of extracellular polymeric substances

The main aim of the study was to determine the inhibitory effects of Ag+ and AgNP (commercial and synthesized) on activated sludge by using respirometry. Along with this aim, also the changes taking place in extracellular polymeric substances (EPS) were studied. Additionally, the binding of Ag+ or AgNP to the different fractions in EPS was assessed using voltammetry. Synthesized AgNP led to an obvious inhibition whereas commercial AgNP had no effect on activated sludge. For Ag+ and AgNP, IC50 values were found between 2.3–3.0mg/L and 3.2–11.1mg/L, respectively. Thus, AgNP was less inhibitory than silver ion, since the release of free silver from AgNP was very small. The protein and carbohydrate content of EPS generally increased when Ag+ was added. Both tightly- and loosely bound fractions in EPS could bind Ag+ and AgNP. Silver binding capacity of EPS was seen to depend on the molecular weight of proteins.

Bismuth film electrode for anodic stripping voltammetric measurement of silver nanoparticle dissolution

A straightforward protocol for measuring low concentration levels of Ag(I) using bismuth film electrode (BiFE) in combination with anodic stripping voltammetry was developed and studied as a suitable alternative to current methods for detecting the dissolution of silver nanoparticles (Ag NPs). The BiFE was prepared in-situ on the surface of a supporting glassy carbon electrode. Several key operational parameters were examined and optimized, e.g. accumulation potential, accumulation time and concentration of Bi(III). The BiFE revealed good linear operation in the examined concentration range of 10–90μgL−1 Ag(I) with r2 of 0.998, calculated limit of detection (3σ) of 2.1μgL−1 obtained after 60s accumulation, and favorable repeatability with RSD of 3.6% (50μgL−1, n=10). The method was successfully tested through measuring Ag(I) in the supernatant of a commercial Ag NP suspension and the performance was superior to the potentiometric measurement using silver ion-selective electrode.

Impact of silver nanoparticles on benthic prokaryotes in heavy metal-contaminated estuarine sediments in a tropical environment

Little knowledge is available about the potential impact of commercial silver nanoparticles (Ag-NPs) on estuarine microbial communities. The Hugli river estuary, India, is susceptible to heavy metals pollution through boat traffic, and there is the potential for Ag-NP exposure via effluent discharged from ongoing municipal and industrial activities located in close proximity. This study investigated the effects of commercial Ag-NPs on native microbial communities in estuarine sediments collected from five stations, using terminal restriction fragment length polymorphism (T-RFLP) technique. An increase in the number of bacteria in consortium in sediments was observed following exposure to Ag-NPs. In general microbial communities may be resistant in estuarine systems to the antimicrobial effects of commercial Ag-NPs, but key microorganisms, such as Pelobacter propionicus, disappeared following exposure to Ag-NPs. In conclusion, the T-RFLP analysis indicated that Ag-NPs have the potential to shape estuarine sediment bacterial community structure.

Synthesis and characterization comparison of peanut shell extract silver nanoparticles with commercial silver nanoparticles and their antifungal activity

Peanut shell extract mediated synthesis of silver nanoparticles (AgNPs), their characterization compared to commercial AgNPs, and the antifungal activity of synthesized and commercial AgNPs were studied. Ultraviolet–Visible spectra (450nm), X-ray diffraction peaks (2θ=39.26, 45.54, 65.12, and 79.21), and Fourier transform infrared spectroscopy confirmed that both AgNPs were similar. High resolution-transmission electron microscopy showed that both the nanoparticles were mostly spherical and oval in shape, with an average particle size of 10 to 50nm. Both the AgNPs (30μg) showed a 5 to 6mm zone of inhibition against the agricultural fungal pathogens Phytophthora infestans and Phytophthora capsici.