Ppm AgNPs Research Articles

In vivo Evaluation of Silver Nanoparticles on the Management of Meloidogyne incognita in Green Gram

In the investigations, on the effect of Ag NPs on the management of M. incognita in green gram, the results showed that all the treatments were found to be effective in increasing all growth parameters. Maximum growth parameter viz., plant height, fresh and dry weight of shoot and root were recorded in the treatment with 0.15 ppm Ag NPs + M. incognita. Maximum reduction in galls, egg masses and final nematode population in soil were recorded in the treatment with 0.15 ppm Ag NPs. All the treatments significantly differed from control except the treatment with 0.0015 ppm Ag NPs + M. incognita.

Nanoparticle-mediated enhancement of plant cryopreservation: Cultivar-specific insights into morphogenesis and biochemical responses in Lamprocapnos spectabilis (L.) Fukuhara 'Gold Heart' and 'Valentine'.

The integration of nanoparticles (NPs) holds promising potential to bring substantial advancements to plant cryopreservation, a crucial technique in biodiversity conservation. To date, little attention has been focused on using nanoparticles in cryobiology research. This study aimed to assess the effectiveness of NPs in enhancing the efficiency of plant cryopreservation. In-vitro-derived shoot tips of bleeding heart (Lamprocapnos spectabilis (L.) Fukuhara) 'Gold Heart' and 'Valentine' were used as the plant material. The encapsulation-vitrification cryopreservation protocol included preculture, encapsulation, dehydration, storage in liquid nitrogen, rewarming, and recovery steps. Gold (AuNPs), silver (AgNPs), or zinc oxide (ZnONPs) nanoparticles were added at various concentrations either into the preculture medium or the protective bead matrix during encapsulation. The explant survival and further morphogenic and biochemical events were studied. Results showed that the impact of NPs on cryopreservation outcomes was cultivar-specific. In the 'Valentine' cultivar, incorporating 5 ppm AgNPs within the alginate bead matrix significantly improved cryopreservation efficiency by up to 12%. On the other hand, the 'Gold Heart' cultivar benefited from alginate supplementation with 5 ppm AgNPs and 5-15 ppm ZnONPs, leading to an over 28% increase in the survival rate of shoot tips. Interestingly, adding NPs to the preculture medium was less effective and sometimes counterproductive, despite promoting greater shoot proliferation and elongation in 'Valentine' explants compared to the control. Moreover, nanoparticles often induced oxidative stress (and enhanced the activity of APX, GPOX, and SOD enzymes), which in turn affected the biosynthesis of plant primary and secondary metabolites. It was found that supplementation of preculture medium with higher concentration (15 ppm) of gold, silver and zinc oxide nanoparticles stimulated the production of plant pigments, but in a cultivar-dependent matter. Our study confirmed the beneficial action of nanoparticles during cryopreservation of plant tissues.

Effect of nanoparticles on the ex-vitro performance of cryopreservation-derived plant material.

The integration of nanoparticles into plant cryopreservation protocols holds great promise for improving the survival rates and recovery potential of explants. This study aimed to verify the effect of nanoparticles on the ex-vitro performance of cryopreservation-derived plants. Lamprocapnos spectabilis (L.) Fukuhara (bleeding heart) 'Gold Heart' and 'Valentine' cultivars were used as the plant material. The encapsulation-vitrification cryopreservation protocol of shoot tips included the preculture, encapsulation, dehydration, storage in liquid nitrogen, rewarming, and recovery steps. Gold (AuNPs), silver (AgNPs), or zinc oxide (ZnONPs) nanoparticles were added at varying concentrations, either into the preculture medium or the protective bead matrix during encapsulation. After the in vitro recovery, the plants were transferred to the glasshouse and subjected to detailed biometrical, biochemical and cytogenetic analyses. Nanoparticles had no evident effect on the acclimatization efficiency (80-100% survival) and leaf number in L. spectabilis 'Gold Heart'. Nonetheless, shoots developed from alginate beads supplemented with 5 ppm AuNPs were twice as long as the control, while the leaves of plants grown on the preculture medium with ZnONPs contained significantly more chlorophyll and had higher Leaf Soil-Plant Analysis Development (SPAD) values. Moreover, several NPs treatments stimulated the development of leaves, including their surface area, length, and perimeter. Higher ZnONPs levels enhanced also the replication process, resulting in higher nuclear DNA content. As for L. spectabilis 'Valentine', alginate augmentation with 5 ppm AgNPs or 5 ppm ZnONPs stimulated the elongation of shoots. There was also a tendency suggesting a positive influence of 5 ppm AgNPs in the alginate bead matrix on foliar growth. The effect of nanoparticles on the content of flavonoids, anthocyanins, and stress markers in the plants varied depending on the treatment and cultivar, but also on the organ studied (leaf or stem). Overall, L. spectabilis 'Gold Heart' was more stress-tolerant and genetically stable than 'Valentine' judging by the activity of Photosystem II (PSII) and flow cytometric analyses, respectively. The complex effects of nanoparticles on survival, biometric parameters, physiological responses, and cytogenetic events underscore the intricate interplay between nanoparticles and plant systems. Nonetheless, our research confirmed the positive effect of nanoparticles on the ex-vitro growth and development of L. spectabilis plants after cryostorage.

Crosslinked hydrogel loaded with chitosan-supported iron oxide and silver nanoparticles as burn wound dressing

Burns can result in infection, disability, psychosocial and economic issues. Advanced wound dressings like hydrogel absorb exudate and maintain moisture. Considering the antimicrobial properties of silver nanoparticles and iron oxide nanoparticles, the efficiency of cross-linked hydrogel loaded with chitosan-supported iron oxide and silver nanoparticles for burn wounds repair was investigated in animal model. Cellulose hydrogel dressing made from carboxymethylcellulose and hydroxyethylcellulose crosslinked with different concentrations of citric acid (10, 15, 20, and 30%) was produced. The physicochemical characteristics of the synthetized hydrogels including Fourier-Transform Infrared spectroscopy, Thermal behavior, Swelling properties, and Scanning Electron Microscope (SEM) were evaluated. The silver nanoparticles and iron nanoparticles were produced and the characteristics, cytotoxicity, antimicrobial activities and their synergistic effect were investigated. After adding nanoparticles to hydrogels, the effects of the prepared wound dressings were investigated in a 14-day animal model of burn wound. The results showed that the mixture comprising 12.5 ppm AgNps, and IONPs at a concentration ≤100 ppm was non-cytotoxic. Moreover, the formulations with 20% CA had a swelling ratio of almost 250, 340, and 500 g/g at pHs of 5, 6.2, and 7.4 after one hour, which are lower than those of formulations with 5 and 10% CA. The total mass loss (59.31%) and the exothermic degradation happened in the range of 273–335 °C and its T m was observed at 318.52 °C for hydrogels with 20% CA. Thus, the dressing comprising 20% CA which was loaded with 12.5 ppm silver nanoparticles (AgNPs) and 100 ppm iron oxide nanoparticles (IONPs) indicated better physicochemical, microbial and non-cytotoxic characteristics, and accelerated the process of wound healing after 14 days. It was concluded that the crosslinked hydrogel loaded with 12.5 ppm AgNPs and 100 ppm IONPs possesses great wound healing activity and could be regarded as an effective topical burn wound healing treatment.

\(\textit{In vitro}\) regeneration of \(\textit{Renanthera imschootiana}\) Rolfe from protocorm-like body

Renanthera imschootiana Rolfe is an extremely rare and endangered tropical epiphytic orchid. Studies on in vitro culture of R. imschootiana were conducted in order to conserve and increase the genetic pool of this wild orchid species. In this study, the effect of plant growth regulators (BA and NAA), ripe bananas in combination with potato, humic acid, and silver nanoparticles (AgNPs) were investigated to find a suitable condition for in vitro plant regeneration from R. imschootiana protocorm-like body (PLB). The results showed that after 45 days of culture, MS medium supplemented with 100 g ripe banana/liter and 100 g potato/liter was suitable for regenerating shoots from the protocorm-like body (PLB) (17.56 shoots/PLBs and 100.00% of shoot-regenerating PLBs); MS medium supplemented with 2.0 mg/L BA, 0.3 mg/L NAA and 4 ppm AgNPs was the most suitable for the growth of shoots after 60 days of culture (10.00 leaves/shoot and shoot length of 4.22 cm). The in vitro shoots were transferred to half-strength MS supplemented with humic acid and AgNPs to investigate the root formation of R. imschootiana. After 60 days of culture, the best rooting was obtained at 2.0 mg/L humic acid and 6 ppm AgNPs (8.33 roots/shoot; root length of 4.00 cm and 100.00% root formation). The findings suggest that the in vitro micropropagation from R. imschootiana protocorm-like body provides a useful alternative tool for the conservation of this endangered species.

Effect of Ag Nanoparticles on Morphological and Physio-biochemical Traits of the Medicinal Plant Stevia Rebaudiana

Nowadays, overproduction of secondary metabolites in remedial herbs through giving biotic/abiotic stresses is an interesting area of research. In the current study, the influences of various concentrations of silver nanoparticles (Ag NPs) were evaluated on several morphological and physio-biochemical traits, such as the steviol glycosides level in Stevia. The findings showed that the herbs incubated with 400-ppm Ag NPs own the highest dry and fresh weight of shoot, while those incubated with 80- up to 200- ppm Ag NPs own the highest steviol glycosides content. As a result, we successfully improve the content of stevioside glycoside up to 1.75-fold by applying the 80- up to 200-ppm Ag NPs in Stevia medicinal plant. Moreover, our findings revealed that low concentrations the Ag NPs lead to an increase of glutathione content and total antioxidant capacity, and a decrease of MDA, whereas treatments at higher concentrations induced adverse effects for the plant. As a result, the treatment with Ag NPs low concentrations had a favorable efficacy on physio-biochemical and morphological characteristics of Stevia. These achievements are very promising, because they revealed a considerable capability for the Ag NPs application in enhancing the secondary metabolites in Stevia remedial herb. The present study is the first case assessing the desirable influences of Ag NPs on the Stevia, in regard with shifting of biosynthetic pathway of steviol glycosides in a concentration-dependent manner.

The impact of dietary inclusion of silver nanoparticles on growth performance, intestinal morphology, caecal microflora, carcass traits and blood parameters of broiler chickens

We evaluated the fects of different levels of dietary silver nanoparticle (AgNP) powder on performance, intestinal microflora, carcass traits and blood parameters of broiler chickens. Three hundred seven-day-old Ross broiler chicks were randomly divided into five groups, each group replicated three times with 20 birds per replication. Chickens were fed the basal diet with 2.5, 5, 10 and 20 mg AgNPs per kg feed. Dietary inclusion of AgNPs improved the final body weight, cumulative weight gain and feed conversion ratio. The best broiler performance, carcass traits, and relative organ weights were observed in the group supplemented with 2.5 ppm AgNPs. Increasing the AgNP dose resulted in a significant decrease in the caecal lactose positive and enterococci bacteria populations, while lactobacilli counts were numerically increased. The silver residues in the breast and thigh muscle significantly increased (p < .05) in a dose-dependent manner. Dietary inclusion of AgNPs induced dose-dependent lesions in liver, kidney, spleen and duodenum tissues involving degeneration, necrosis, mononuclear infiltration and focal aggregation of inflammatory cells. In conclusion, despite its potential positive impacts on growth performance, carcass traits and caecal microbial population diversity at a dose of 2.5 ppm, dietary inclusion of AgNPs had the following negative effects on broilers: 1) silver residues in breast and thigh muscle, which may result in AgNPs transmission to consumers, and 2) cytotoxicity in intestinal, liver, spleen and kidney cells in a dose-dependent manner. Therefore, we suggest the use of lower doses of AgNPs (< 2.5 ppm diet) in poultry production in the future studies. HIGHLIGHTS Dietary inclusion of silver nanoparticles (AgNPs) in broiler diets more than 2.5 mg/kg diets had many negative effects represented by accumulation of silver residue in broiler meat and the possibility of transmission of nanosilver to consumers. AgNPs had a cytotoxic effect on intestine, liver, spleen and kidney cells in a dose-dependent manner in broilers and might be harmful to chicken and human health. Therefore, we do not recommend using AgNPs as a dietary growth promotor or antibacterial agent in broiler diets and their use and marketing should be controlled and restricted.

Extending vase life of carnation flowers by postharvest nano silver, humic acid and Aloe Vera gel treatments

Abstract Standard Carnation flowers (Dianthus caryophyllus cv. Dover) were harvested at the paint brush stage in the early morning, pre-cooled at 4° C for 6-h then moved under dry conditions to the laboratory. Flowers were weighted and treated for 24-h with silver nanoparticles (AgNPs) at 0, 5 or 10 ppm in plastic buckets. After pulsing treatments, cut flowers were transferred to 500 mL glass jars containing 300 mL of preservation solution treatments including, individually, humic acid at 200, 400 or 600 ppm and Aloe vera gel at 2.5%, 5.0% or 7.5% (w/v) till the end of the experiment (when flower color began to fade, petals began to roll). Distilled water was used for the control and to prepare the tested solutions. 2% sucrose was added to all treatments including the control. Addition of all preservatives to vase solutions significantly increased all the studied characteristics of cut flowers compared to control (distilled water, least values). Nanosilver treatments have the potential to be used as preservative solutions for improving postharvest vase life and quality of carnation flowers. An increment in vase life, relative fresh weight, vase solution uptake, flower diameter as well as total chlorophylls in leaves, total carbohydrates and total phenols in leaves and petals was observed, in addition to a decrease in bacterial counts in vase solution. Best results were obtained using 5 ppm AgNPs + 5.0% Aloe vera gel followed by 5 ppm AgNPs +7.5% Aloe vera gel solutions. Aloe vera gel, especially 5.0% level, showed better results than humic acid when used alone or combined with AgNPs. Nanosilver at 5 ppm recorded better results than 10 ppm when used as a single treatment.

Synthesis, Characterization, and Optimization of Green Silver Nanoparticles Using Neopestalotiopsis clavispora and Evaluation of Its Antibacterial, Antibiofilm, and Genotoxic Effects

Abstract Silver nanoparticles (AgNPs) have been used in a variety of biomedical applications in the last two decades, including antimicrobial, anti-inflammatory, and anticancer treatments. The present study highlights the extracellular synthesis of silver nanoparticles AgNPs using Neopestalotiopsis clavispora MH244410.1 and its antibacterial, antibiofilm, and genotoxic properties. Locally isolated N. clavispora MH244410.1 was identified by Internal transcribed spacer (ITS) sequences of nuclear ribosomal DNA. Optimization of synthesized AgNPs was performed by using various parameters (pH (2, 4, 7, 9 and 12), temperature (25, 35 and 45 °C), and substrate concentration (0.05, 0.1, 0.15, 0.2 and 0.25 mM)). After 72 hours of incubation in dark conditions, the best condition for the biosynthesis of AgNPs was determined as 0.25 mM metal concentration at pH 12 and 35 °C. Fungal synthesized AgNPs were characterized via spectroscopic and microscopic techniques such as Fouirer Transform Infrared Spectrophotometer (FTIR), UV-Visible Spectroscopy, and Transmission Electron Microscopy (TEM). The average size of the AgNPs was determined less than 60 nm using the TEM and Zetasizer measurement system (measured in purity water suspension). The characteristic peak of AgNPs was observed at ~414 nm from UV-Vis results. Antibacterial and genotoxic activity of synthesized AgNPs (0.1, 1, and 10 ppm) were also determined by using the agar well diffusion method and in vivo Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster. AgNPs exhibited potential antimicrobial activity against all the tested bacteria (Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa) except Escherichia coli in a dose-dependent manner. AgNPs did not induce genotoxicity in the Drosophila SMART assay. 79.33, 65.47, and 41.95% inhibition of biofilms formed by P. aeruginosa were observed at 10, 1, and 0.1 ppm of AgNPs, respectively. The overall results indicate that N. clavispora MH244410.1 is a good candidate for novel applications in biomedical research.

Impact of silver nanoparticles and two biological treatments to control soft rot disease in sugar beet (Beta vulgaris L)

BackgroundSoft rot disease caused by Pectobacterium carotovorum was observed in various crops which lead to yield shortages and economic losses.Main bodyTherefore, both in vitro and in vivo experiments, aim to assess the effect of nanoparticles and biological treatments to control soft rot disease in sugar beet plant. The treatments comprised three silver nanoparticles (Ag NPs) concentrations (50, 75, and 100 ppm), three Spirulina platensis extract concentrations (50, 75, and 100%), and Bacillus subtilis (1 × 109 CFU ml) 100%. Under in vitro condation, results of the antibacterial activity showed that the zones of inhibition recorded 4.33 cm for 100 ppm Ag NPs, 0.43 cm for 100% algal extract, and 0.2 cm for bacterial treatments. Also, disease incidence % of bacterial soft rot was significantly decreased in all treatments in pot and field experiments. For resistant enzymes activity, B. subtilis 100% showed the most effect (84 mg min−1), followed by S. platensis extract 75%, (57 mg min−1), and Ag NPs 75 ppm (44 mg min−1), for poly phenol oxidase (PPO) at 81 days after sowing (DAS), but at 102 DAS revealed opposite results. On the contrary, peroxidase (PO) at 81 DAS showed different effects where treatment with S. platensis extract 100% increased it significantly (0.546 mg min−1) compared to control (0.535 mg min−1). The same trend was observed at 102 DAS. These results were reflected on sugar quality where Ag NPs 100 ppm treatment recorded the highest significant value (20.5%) followed by S. platensis 75% (19 %); however, the differences among them were not statistically significant.ConclusionThis study indicated that the potential benefits of using silver nanoparticles and two biological treatments to control soft rot disease in sugar beet (Beta vulgaris L).

Performance, intestinal microbial population, immune and physiological responses of broiler chickens to diet with different levels of silver nanoparticles coated on zeolite

The aim of this study was to evaluate the effects of different levels of silver nanoparticles (Ag-NPs) coated on zeolite on performance, gastrointestinal microflora, heterophile to lymphocyte ratio and humoral immune system responses of broiler chickens. Three hundred seventy-five chicks (Cobb 500) in a completely randomised design were distributed to five diets: 1) basal diet, 2) basal diet containing 1% zeolite and 3, 4 and 5) basal diet containing 1% zeolite coated with 25, 50 and 75 ppm Ag-NPs. Performance traits were recorded and blood samples were taken to determine antibody response against Newcastle on day 14, infectious bursal disease on day 21 and serum immunoglobulins (Igs) were determined on day 42. Heterophile to lymphocyte ratio was evaluated on days 28, 35 and 42. The result showed that feed conversion ratio (FCR) was significantly decreased in Ag-NP treatments compared with control group (p < .05). Total anaerobic bacteria and the population of Escherichia coli in ileum and caecum were decreased (p < .05). The highest number of lactobacillus was observed in NS50 (p < .05). Antibody response against Gumboro was decreased as well as the amount of IgY antibody in Ag-NPs treatments. Significant differences were observed in heterophile to lymphocyte ratio on day 28 and 35 and the highest amount was observed in NS50 group (p < .05). In conclusion, although this study showed that using Ag-NP dietary coated on zeolite could improve gut microflora, but Ag-NPs could also have side effects on the immune mechanism of broiler chickens. Highlights Silver nanoparticles (Ag-NPs) coated on zeolite improved feed efficiency at different levels. Ag-NPs (50 ppm) coated on zeolite reduced Escherichia coli number and decreased lactobacillus number. Ag-NPs (50 ppm) coated on zeolite decreased antibody response against Gumboro and amount of IgY antibodies.

The effect of silver nanoparticles on the limitation of ethylene gas and hydrolytic enzymatic activity in micropropagation of rose (Rosa hybrida L. 'Baby love')

Micropropagation of rose (Rosa hybrida L. ‘Baby Love’) often encounter some abnormal phenomena such as yellow and abscission leaf, hyperhydricity, etc. These phenomena effect on the quality of shoots cultured in vitro as well as the survival rate of plantlets after transferred to greenhouse. This is due to the accumulation of ethylene in culture vessel, which leads to an increase in enzyme activity of cellulase and pectinase resulted in disrupting the cell wall binding and inducing organ abscission. In this study, the effect of silver nanoparticles (AgNPs) to overcome these abnormal phenomena as well as its effect on the growth and development of shoots and plantlets in rose cultured in vitro were evaluated. The results showed that after 6 weeks of shoot culture, the medium supplemented with 2 ppm AgNPs was the most suitable for in vitro shoot multiplication with the highest number of shoots/explant (6.67 shoots), shoot height (3.06 cm), fresh weight (451.00 mg), dry weight (58.33 mg), SPAD (32.28) and dry mass ratio(12.33%). Adding 3 ppm AgNPs into in vitro rooting medium may improve the growth and develop involve in plant height (3.06 cm), number of leaves (6.33), leaf length (1.50 cm), leaf width (1.50 cm), fresh weight (137.67 mg), dry weight (13.00 mg), number of roots (4.33), SPAD (39.37), dry mass ratio (9.40%) of rose plantlet after 4 weeks of culture. After treatment with AgNPs, the abnormal phenomena including ethylene gas accumulation (0.30 ppm), cellulase enzyme activity (0.14 UI/mL) and pectinase enzyme activity (0.40 UI/mL) was reduced compare with the other treatments and the control. In addition, the high survival rate (93.33%) of plantlets was also observed after 4 weeks transferred to greenhouse. On the other hand, the treatment with 5 ppm AgNPs also induced early rose in vitro flowering; however, when using AgNPs at high concentrations (7 ppm) inhibited growth, development, toxicity and even death of explants.

Nanocomposite starch-based films containing silver nanoparticles synthesized with lemon juice as reducing and stabilizing agent

Silver nanoparticles (AgNP L) synthesis using the active compounds of lemon juice was optimized. The obtained nanoparticles were included in starch-based film formulations, studying the relevant properties that condition their application in the packaging area. The optimized conditions for AgNP L’ synthesis were 30 min at 90 °C, which led to the lowest nanoparticle size (5.5 nm) with the highest associated stability (ζ= −29.5 mV) up to 90 days. Nanocomposite films resulted with an orange tone that increased with AgNP L concentration (14.3–143 ppm). Water vapor permeability decreased while tensile mechanical resistance increased up to an aggregate of 71.5 ppm of AgNP L, indicating the nanoparticles’ reinforcement of the polymer matrix. Besides, the citric acid content provided by lemon juice also affected the starch-based relevant film properties. Regarding antimicrobial capacity, a synergic effect between active compounds of lemon juice and silver nanoparticles was evidenced, being Salmonella spp. the most sensitive bacteria.

Antibacterial activity of synthesized silver nanoparticles by sumac aqueous extract and silver-chitosan nanocomposite against Pseudomonas syringae pv. syringae

The considerable damages caused by plant pathogenic bacteria have prompted the use of a wide variety of chemical pesticides which cause harmful effects on human health and environment. Application of safe and eco-friendly methods for controlling plant pathogens is very important in sustainable agricultural systems. In this present study, the biosynthesis of silver nanoparticles was conducted using sumac aqueous extract. Antibacterial activity of synthesized AgNPs (with the average size of 35 nm) and their combination with chitosan (Cs) was evaluated against Pseudomonas syringae pv. syringae (Pss), the causal agent of bacterial canker disease of stone fruit trees in vitro and in vivo. The structure and physical properties of nanoparticles were investigated by scanning electron microscope, X-ray diffraction, and UV-visible spectrophotometer. Green synthesized AgNPs and Cs-Ag nanocomposite indicated minimum inhibitory concentration at 12 ppm and 9.2 ppm Cs/4 ppm AgNPs, respectively. Also, in vitro evaluations showed that chitosan could improve the antimicrobial property of silver nanoparticles. In greenhouse experiments, the results showed that different concentrations of AgNPs and Cs-Ag nanocomposite reduced disease severity of bacterial canker of stone fruits on two-year-old peach trees when compared to the control. The highest decreases were caused using 100 ppm concentration of AgNPs (89.40%) and then a combination of 100 ppm AgNPs/231.48 ppm chitosan (86.61%). This study suggests that the synthesized AgNPs act as eco-friendly antibacterial agents. But, further studies should be conducted to develop nanoparticles with the minimum toxicity and maximum antimicrobial effect to apply as proper alternatives for antibiotics and pesticides.

Effects of silver nanoparticles on the growth, mortality rate and morphology of Chlorella vulgaris and Thalassiosira weissflogii algae

In this paper, we study the effects of silver nanoparticles (AgNPs) on the growth of two species of algae, Chlorella vulgaris and Thalassiosira weissflogii. The AgNPs used in this experiment were chemically synthesised from a AgNO3 salt, with an average particle size of 7 nm in diameter. The test was conducted with five concentrations of AgNPs including 0 (control), 0.01, 0.1, 1 and 10 ppm. The results show that T. weissflogii is more sensitive to the solution of AgNPs than C. vulgaris. In particular when AgNPs solution is added to Erlenmeyer flask microalgae cultures from the start, the concentrations of 0.01 ppm and 0.1 ppm AgNPs do not affect the growth of C. vulgaris. They reach a stationary phase from the eighth to the tenth day of the experiment; the maximum algae density is not different from that of the control. At a concentration of 1 ppm AgNPs, C. vulgaris is completely dead after 96 h of exposure, and at a 10 ppm concentration, the algae is completely dead after 48 h of exposure. However, for T. weissflogii, AgNPs at a concentration of 0.01 ppm do not affect growth. From a concentration of 0.1 ppm, AgNPs alter the growth curve of algae, the maximum density of algae is lower than that of the control, and from a concentration of 1 ppm AgNPs, the algae are totally dead after 24 h of exposure.

Effect of Nano Technology in Combination with Soil Solarization to Control Panama Disease of Banana in Jordan Valley

Soil solarization was applied for a field which was planted with infected banana seedlings. Spreading transparent plastic sheets of 80µ thickness was done from August, 1 until October 12, 2017 at the University Farm in Jordan Valley. Soil solarization was effective in elimination of all phytopathogenic propagules at 30 cm depth. Then clear plastic sheets were removed and the solarized land was planted with healthy banana seedlings cultivar Grand Naine. Banana plantlets were chemically treated as soil drench with Nanoparticle solution of 200 and 400 ppm of Silver Nanoparticles (AgNPs), two fungicides, Revanol and Tachigaren, Sodium Hypochlorite in addition of irrigation of one treatment with treated wastewater. Biological control included three treatments; Endomycorrhiza, Trichoderma as a commercial product (BioHealth) and plant growth promoting rhizo-bacteria. Fresh chicken and sheep manure was added to two treatments. Twelve treatments were distributed randomly in randomized complete block design. Endomycorrhizal inoculation with Glomus mosseae, 200 ppm of AgNPs, Revanol and Tachigaren treatments of banana seedlings were the most effective in completely protecting banana plants from Fusarium wilt during the whole experimental period. Several applications of Trichoderma, wastewater and 400 ppm of AgNPs were effective in maintaining some infected banana seedlings nine months after planting very healthy. Sheep and chicken manure treatments resulted with 60 and 40% disease incidence with Fusarium wilt respectively and 20% of disease incidence in Hypex, PGPR and control treatments. Wastewater, Nanoparticles 200 ppm and endomycorhizal treatments gave the highest ratio of sword sucker development. We recommend soil solarization and use of integrated program to control Panama disease of banana in Jordan.

A Ferritin Photochemical Synthesis of Monodispersed Silver Nanoparticles That Possess Antimicrobial Properties

We previously reported that ferritin acts as a photocatalyst to form monodispersed gold nanoparticles. Because silver possesses a favorable reduction potential (+0.80 V), we postulated that the ferritin photochemical method could be used to reduce Ag(I) to Ag(0). Additionally, we postulated that similar to gold, the reduced silver should nucleate and form silver nanoparticles (AgNPs) on the external surface of ferritin. This study reports that Ag(I) can function as an electron acceptor to form monodispersed AgNPs using the ferritin photocatalytic method. The formation and growth of the AgNPs were monitored by following the surface plasmon resonance (SPR) peak at 420 nm by spectrophotometry. The resulting monodispersed AgNPs were analyzed by transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and energy-dispersive X-ray spectroscopy (EDX). Gel filtration chromatography demonstrated that the AgNPs comigrated with ferritin through the column suggesting a strong association with ferritin. AgNPs are known to possess antimicrobial properties. The antimicrobial properties of Ferritin-AgNPs were compared to commercially available AgNPs by testing the minimal growth inhibition ofStaphylococcus aureus. Commercially available AgNPs inhibited bacterial growth at 5 ppm AgNPs, and Ferritin-AgNPs inhibited growth at 20 ppm Ferritin-AgNPs.

Plasma sprayed rutile titania-nanosilver antibacterial coatings

Rutile titania (TiO2) coatings have superior mechanical properties and excellent stability that make them preferential candidates for various applications. In order to prevent infection arising from bacteria, significant efforts have been focused on antibacterial TiO2 coatings. In the study, titania-nanosilver (TiO2/Ag) coatings with five different kinds of weight percentages of silver nanoparticles (AgNPs) were prepared by plasma spray. The feedstock powders, which had a composition of rutile TiO2 powders containing 1–10,000ppm AgNPs, were double sintered and deposited on stainless steel substrates with optimized spraying parameters. X-Ray diffraction and scanning electron microscopy were used to analysize the phase composition and surface morphology of TiO2/Ag powders and coatings. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were employed to examine the antibacterial activity of the as-prepared coatings by bacterial counting method. The results showed that silver existed homogeneously in the TiO2/Ag coatings and no crystalline changed happened in the TiO2 structure. The reduction ratios on the TiO2/Ag coatings with 10ppm AgNPs were as high as 94.8% and 95.6% for E. coli and S. aureus, respectively, and the TiO2/Ag coatings with 100–1000ppm AgNPs exhibited 100% bactericidal activity against E. coli and S. aureus, which indicated the TiO2/Ag coatings with more than 10ppm AgNPs had strong antibacterial activity. Moreover, the main factors influencing the antibacterial properties of TiO2/Ag coatings were discussed with grain size and the content of silver as well as the microstructure of the coatings.

Change of antioxidant enzymes activity of hazel (Corylus avellana L.) cells by AgNPs.

Elicitation effect of silver nano particles (AgNPs) and triggering of defence system by production of hydrogen peroxide (H2O2) as a signaling molecule in the regulation of the activity of stress-related enzymes and production of Taxol was evaluated in suspension- cultured hazel cells (Corylus avellana L.). The cells were treated with different concentrations of AgNPs (0, 2.5, 5, and 10ppm), in their logarithmic growth phase (d7) and were harvested after 1 week. Treatment of hazel cells with AgNPs decreased the viability of the cells. Also the results showed that while the activity of certain radical scavenging enzymes in particular of catalase and peroxidase increased by 2.5 and 5ppm AgNPs, the activity of superoxide dismutase decreased in these treatments. The highest activity of ascorbate peroxidase was observed in 10ppm AgNPs treatments. This treatment also showed the highest contents of H2O2 and phenolic compounds, as well as the highest activity of phenylalanine ammonialyase. According to the results, 5ppm AgNPs was the best concentration for elicitation of hazel cells to produce efficient amounts of H2O2 in order for stimulation of antioxidant defence system, production of Taxol at the highest capacity of the cells, meanwhile reserving their viability.

Influence of Water Hardness on Silver Ion and Silver Nanoparticle Fate and Toxicity Toward Nitrosomonas europaea.

This study investigated the influence of water hardness (Mg2+ and Ca2+) on the fate and toxicity of 20 nm citrate silver nanoparticles (AgNPs) and Ag+ toward Nitrosomonas europaea, a model ammonia-oxidizing bacterium. Nitrification inhibition of N. europaea by 1 ppm AgNPs and 0.5 ppm Ag+ was reduced from 80% and 83%, respectively, in the absence of Mg2+ to 2% and 33%, respectively, in the presence of 730 μM Mg2+. Introduction of Mg2+ resulted in the rapid aggregation of the AgNP suspensions and reduced the 3 h Ag+ dissolution rates from 30%, in the absence of Mg2+, to 9%, in the presence of 730 μM Mg2+. Reduced AgNP dissolution rates resulted in decreased concentrations of silver that were found adsorbed to N. europaea cells. Increasing AgNP concentrations in the presence of Mg2+ increased the observed inhibition of nitrification, but was always less than what was observed in the absence of Mg2+. The presence of Mg2+ also reduced the adsorption of Ag+ to cells, possibly due to multiple mechanisms, including a reduction in the negative surface charge of the N. europaea membrane and a competition between Mg2+ and Ag+ for membrane binding sites and transport into the cells. Ca2+ demonstrated similar protection mechanisms, as Ag+ toxicity was reduced and AgNP suspensions aggregated and decreased their dissolution rates. These results indicate that the toxicity of Ag+ and AgNPs to nitrifying bacteria in wastewater treatment would be less pronounced in systems with hard water.