Showing 18 results for Silver Nanoparticles
Volume 2, Issue 3 (7-2016)
Abstract
Background: This study was performed to determine antifungal activity of silver nanoparticles (nano-Ag) compared to voriconazole on clinical and standard strains of Aspergillus fumigatus.
Materials and Methods: Inhibitory potency of nano-Ag was determined using microtiter broth dilution method. Susceptibility tests were performed against A. fumigatus isolated from BAL (bronchoalveolar lavage) of patients who suffered from respiratory problems and compared with the strain (ATCC: 204305) by broth dilution antifungal susceptibility test of filamentous fungi approved by the Clinical and Laboratory Standards Institute M38-A. In addition, cytotoxicity effect of silver nanoparticles was studied on epithelial cell line by MTT assay.
Results: From 60 BAL samples the following strains were isolated; A. flavus (n=21), A. niger (n=3), and A. fumigatus (n=1). The minimum inhibitory concentration (MIC90) values of nano-Ag were 0.25 and 0.5 μg.mL-1 for standard strain and clinical isolates respectively. The Minimum Fungicidal Concentration (MFC) values of nano-Ag were 0.5 and 1 μg.mL-1for standard strain and clinical isolates respectively. MIC90 values of voriconazole were 0.125 and 0.25 μg.mL-1 for standard strain and clinical isolate respectively. The MFC values of voriconazole were 0.25 and 0 μg.mL-1 for standard strain and clinical isolates respectively. Silver nanoparticles exhibited low cytotoxicity in 0.25 μg.mL-1 concentration.
Conclusion: Our results showed high antifungal activity of silver nanoparticles against Aspergillus isolates. Furthermore, the availability of a wide form of nano-Ag structures can be considered as novel agents to decrease fungal burden in medical application.
Behrooz Mohamadi, Mojtaba Salouti, Ali Haniloo,
Volume 3, Issue 2 (11-2012)
Abstract
In biological methods, microorganisms such as bacteria, fungi, actinomycets and yeasts are used to produce metal nanoparticles. Fungi are extremely good candidates in the synthesis of silver nanoparticles because of their ability to secrete large amounts of enzymes. The aim of this study was the biosynthesis of silver nanoparticles by Penicillium spp. isolated from the soil of plump and zinc mine in Zanjan city (Iran). After culturing, growth of colonies and isolation of Penicillium spp., 15 g of the fungal biomass was mixed into 1 mM silver solution for 72 h incubation. The production of silver nanoparticles was characterized by UV-vis spectroscopy, X-ray diffraction(XRD) and transmission electron microscopy. Among the sixteen kinds of isolated fungi, six species were recognized as Penicillium of which just the fungus Penicilliumbrevicompactum was found to be able to produce silver nanoparticles. The production of silver nanoparticles was preliminarily approved by observing the color change of the reaction solution from colorless to yellowish brown. The synthesis of silver nanoparticles was confirmed by observing the characteristic peak at 406-425 nm. The presence of crystalline silver nanoparticles was confirmed by observing peaks in (111), (200), (220), (311) in the XRD analysis. Transmission electron microscopy images showed that silver nanoparticles were produced in the size range of 50 -100 nm in spherical shape mainly extracellular at the surface of mycelium. The fungus was recognized to be Penicilliumbrevicompactumusing slide culture method, growth on Czapek yeast agar and Keratin-sucrose agar.
Volume 5, Issue 1 (6-2016)
Abstract
Silver nanoparticles (AgNPs) are widely used in consumer products mainly due to their antimicrobial action. The rapid increase in the use of nanoparticles has driven more attention to their possible ecotoxicological effects. In this study: first, acute effects of colloidal AgNPs during embryonic stage of Persian sturgeon and Starry sturgeon were investigated and then in Starry sturgeon, their short-term effects during early life stages (before active feeding commences) were analyzed. Based on the obtained results from the acute toxicity tests, AgNPs induced a dose-dependent toxicity in both species during early life stages. The short-term toxicity test was performed using 0, 0.025, 0.05 and 0.1 mg/l of colloidal AgNPs. Silver accumulation in larvae exposed to 0.1 mg/l AgNPs was recorded significantly higher than the control treatment (P<0.05). However, the obtained survival rate data did not indicate any significant differences among treatments.
Taher Mohasseli, ,
Volume 6, Issue 1 (10-2015)
Abstract
Nanotechnology involves technological research and development in spaces at the range of 1 to 100 nanometers, and in this technology, very small and atomic scale particles are created and handled. Plant extracts can be used as a green method for the synthesis of silver nanoparticles. In this study, the biosynthesis of silver nanoparticles was performed using extracts of sesame (Sesamum indicum) seeds. Silver nitrate was added to the seed extract, and then it was incubated at 30 ° C. The effects of three concentrations (1mM, 2mM and 3mM) of silver nitrate on the synthesis of silver nanoparticles were studied. The analyses of absorption spectroscopy UV-Visible, Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD) and Inductively Coupled Plasma (ICP) were conducted to assess the production of nanoparticles. UV-Visible spectroscopy analysis and the peak at 420 nm indicated the occurrence of nanoparticles in the extract. TEM image determined that the nanoparticles were spherical with average size of about 14 nm. XRD analysis showed the nano-crystals synthesized by the extract, and Inductively coupled Plasma (ICP) determined the conversion percentage of silver ion into silver nanoparticle as approximately 99.61 percent.
Volume 7, Issue 4 (12-2018)
Abstract
The use of environmentally friendly methods is one of the new approaches in combating pathogens in aquaculture systems. The purpose of this research was the possibility evaluation of indirect use of Ag-NPs-coated porous ceramic in water filtration of culture system of shrimp post-larvae to control Vibrio harveyi. In this study, Ag-NPs-coated filters were characterized by various analytical techniques such as FTIR, XRD, ICP, and SEM. In this study, the antibacterial activity of Ag-NPs-coated on porous ceramic against mentioned bacteria via in vitro experiments Zone of inhibition test and Test tub test were determined. Then porous ceramic filter media used for water treatment. Therefore, the performance of the Ag-NPs-coated on porous ceramics in removing pathogenic bacteria was studied in two phases: In the first phase, V. harveyi was inoculated to the water and efficacy of filters of inhibition of bacteria was evaluated via total count of bacteria in the test water; in the second phase, the performance of the Ag-NPs-coated on porous ceramic was tested in the presence of shrimp larvae and efficacy of filters in inhibition of bacteria was evaluated via total count of bacteria, mortality rate, clinical signs, and also hepatopancreas and muscle culture. Based on the results, the highest zone of inhibition obtained in presence of Ag-NPs-coated porous ceramic modified by an aminosilane coupling agent, 3-Amino-Propyl-Triethoxysilane (APTES; the samples were immersed in the silver colloidal solution for 24h). The results of the flow test showed the highest bacteria removal efficiency from water with complete removal of the targeted pathogen. In the second phase, the results indicated a significant difference in decreasing of water bacteria, shrimp mortality and disease symptoms in treatment containing silver compounds compare to controls. According to results, Ag-NPs-coated porous ceramic have a high bacteria removal efficiency for the disinfection of water of culture system of shrimp to control Vibrio harveyi.
Omid Azizian Shermeh, Moharam Valizadeh, Jafar Valizadeh, Mozhgan Taherizadeh, Maryam Beigomi,
Volume 8, Issue 1 (4-2017)
Abstract
Microorganisms and plants have high potential for reducing the metal (biosynthesis of nanoparticles) through their metabolic pathways. Apart from the environmental benefits of biosynthesis of nanoparticles, there is the opportunity for production of nanomaterial with new properties in this method. In this study, the fruit aqueous extract of Capparis spinosa L. was used for synthesis of nanoparticles. To evaluate the reducing potential of plant, total phenolic content and antioxidant activities of both aqueous and ethanolic extracts were measured by DPPH and FRAP methods. The aqueous extract showed a lower antioxidant activity than the ethanolic extract; however, it had high potential to reduce the free radicals and metal ions. After preparing the extract, for phytosynthesis of silver nanoparticles, 2 ml of extract was added to 4 ml of 1 mM silver nitrate. The extract was used as a reducing and stabilizing agents of the nanoparticles. The effect of determining parameters for optimizing synthesis of nanoparticles such as: pH of reaction, the amount of extract, concentration of metal ion and time of reaction were evaluated using Ultraviolent-Visible (UV-Vis) spectroscopy and Transmission Electron Microscopy (TEM) .The spectrum of Surface Plasmon Resonance (SPR) of silver nanoparticles showed the maximum absorbance at 415 nm. Fourier Transform Infrared (FT-IR) spectroscopy was used to identify the possible functional groups involved in the synthesis of silver nanoparticles. The Results showed that the nanoparticles were spherical shape and the size of them were about 8-12 nm.
, , ,
Volume 8, Issue 2 (10-2017)
Abstract
Nanotechnology is a principally attractive area of research related with production of nanoparticles of variable sizes, shapes, chemical compositions and their possible application for human being benefits. Creation, manipulation and utilization of metallic nanoparticles, because of reduction of materials dimensions, affect the physical properties and results in displaying extraordinary thermal, optical and electronic properties of nonmaterial. The biological approaches to synthesis of nanoparticles are better than chemical and physical procedures because of low energy and time expenditure.
In this study the possibility of production of nano-silver particles from dried flower buds of Clove was investigated and antibacterial and anti-fungal activities of produced nanoparticles were studied by diffusion disc and well methods. The displayed UV-visible spectra, with a wavelength of 300 to 600 nm, identifies formation of silver nanoparticles, whenever the colorless initial acclimated mixture turned to brown. The centrifuged powder samples were examined using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) methods. Based on the results of this study, produced silver nanoparticles were spherical in the range of 27 to 69 nm and showed effective antimicrobial activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus and Saccharomyces cerevisiae. Therefore clove can be used as a biological source for the synthesis of nanoparticles in an industrial scale with a very low cost.
S. Mashjoor , M. Alishahi , Z. Tulaby Dezfuly ,
Volume 9, Issue 3 (9-2018)
Abstract
Aims: The bio-toxicity of silver nanoparticles (AgNPs) in the aquatic ecosystem and the detection of lethal concentrations of this material are of importance. The aim of this study was in vivo comparative toxicity of silver nanoparticles and bio-productivity in zebrafish (Danio rerio) in embryo and adult stages.
Materials and Methods: The present experimental study was carried out on 30 fertilized eggs and 30 adult zebrafish and the effects of chemical and bio-productivity of AgNPs were evaluated by brown seaweed (Sargassum boveanum) in evolutionary stages of the embryo and adult zebrafish with a control group and in incremental concentrations. The mortality rate was recorded at 24, 48, 72, and 96 hours after exposure and the data were analyzed by EPA Probit Analysis 1.5 and SPSS 19 softwares, using one-way analysis of variance and Duncan's multiple range test.
Findings: The toxicity of both types of AgNPs in both evolutionary stages was increased with increasing concentrations and time (p<0.05). After 96 hours, the lethal concentration 50 (LC50) in adult fish was 0.788mg/l for chemical AgNPs and 0.409mg/l for bio-produced AgNPs. Mortality rate at the highest concentration (3mg/l) of AgNPs at 72 and 96 hours in all groups was 100%.
Conclusion: Comparison of the toxicity result showed that the biosynthesis form of AgNPs is more toxic potential than chemical form of AgNPs. It seems the sensitivity of embryo stage to both of silver nanoparticles more than to mature stage.
B. Ramezani, I. Alamzadeh, M. Vossoughi, M. Hajiabbas,
Volume 10, Issue 3 (9-2019)
Abstract
Burns are one of the most important accidents related to human health. Receiving proper treatment is very important due to the intense complications associated with them. The improvement and elimination of ulcer effect can be achieved by controlling the wound infection. According to this, wound dressing containing antibiotics is one of the effective methods in wound's infection treatment. The use of silver in burns caring has been considered a long time ago, but silver deposits on the liver that causes some problems which can be overcome with the help of nanotechnology. In this study, Silver-Oak nanoparticles were green synthesized by using the ethanol extraction of Iranian Oak with the help of reducing agent. Nanoparticles formation were followed by UV-Visible spectrum and they characterize with SEM images and XRD spectrum. Then Gelatin-Alginate Hydrogel was prepared as a wound dressing and their properties were investigated by the presence of nanoparticles, oak extraction and without any additives. Nanoparticles' diameter is about 30-65nm which are dispersed in the hydrogel with regular pore size about 30-100μm. Oak extraction increase the hydrogel water uptake that improve the wound hilling. Antibacterial properties of wound dressing against Staphylococcus aurous and pseudomonas are investigated by inhibiting zone.
Elham Keikha, Abbasali Emamjomeh, Mohharam Valizadeh, Baratali Fakheri,
Volume 11, Issue 2 (6-2020)
Abstract
Today, nanosilver is one of the most commercialized nanomaterials. The demand for synthesis of Nanosilver through biocompatible routs due to wide biomedical application has increased. Use of plants and plant products as sustainable and renewable resources in the synthesis of nanoparticles is more advantageous over other biological routes. In this study, biosynthesis of silver nanoparticles (AgNPs) using aqueous extract of Withania somnifera as reducing agent is reported. Effect of parameters such as AgNO3 concentration, aqueous extract, pH and formation time were investigated and optimized by UV-visible spectroscopy in the synthesis of nanoparticles. At room temperature, the solution color started to change from pale yellow to dark brown due to the reduction of silver ion. The transmission electron microscopy (TEM) was applied for size and morphological analysis of nanoparticles. TEM result shows a spherical structure with an average size ranging from 24-35 nm for silver nanoparticles.
Nasrin Fazelian, Morteza Yousefzadi, Ahmad Ahmadi,
Volume 11, Issue 2 (6-2020)
Abstract
Objectives: In this study, the effect of different concentrations (1-50 mg/L) of colloidal Ag-NPs investigated on the growth, fatty acids profile and biodiesel indices of N. oculata, after estimating EC50 (20.88 mg/L).
Materials and methods: In this research, N. oculata was selected owing to fast growth and its ability to synthesize lipids for biodiesel production. This microalga exposed to colloidal silver nanoparticles under marine conditions for 72 h. The optical density (OD) and fatty acid profiles were investigated using spectrophotometric analysis and gas chromatography, respectively. Statistical analysis growth data was performed using ANOVA and Duncan's multiple test at 2% probability level.
Results: The algal growth significantly decreased in N. oculata cells treated with the 5-50 mg/L of Ag-NPs. The increase of saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) as well as the decrease of monounsaturated fatty acids (MUFAs) contents were also observed in response to 25 mg/L of Ag-NPs in compared to the control. The important indicators of biodiesel oxidative stability containing LCSF, CFPP and CP increased in N. oculata exposed to Ag-NPs, while the level of DU decreased. The results of this study showed that despite the toxicity of silver nanoparticles, this nanoparticle can increase the biodiesel stability produced from N. oculata.
Impregnation of porcelain pots with Silver Nanoparticles by an innovative pervaporation technic and study of the effects on food stock pathogens (Escherichia coli, Staphylococcus aureus)
Tavakolian, S.1, Manteghian, M.2, Asadi,Gh.3, Najarpiraie, Sh.4, Shabani, Sh. 5
Volume 11, Issue 45 (3-2014)
Abstract
Growth of Pathogenic microorganisms is one of the major obstacles in the food industry. An innovative method has been introduced for impregnating porcelain pots with antimicrobial silver nanoparticles. Silver nanoparticles have been produced by reducing silver nitrate with hydrazine. Particles have then been impregnated in porcelain pottery using a pervaporation technique. Samples of the pots have been analysed by SEM, EDX, XRD and AFM. Antibacterial properties of the pottery have been confirmed by exposing them in broths containing Escherichia coli and Staphylococcus aureus while the destructive effects have more profoundly been detected on gram negative Escherichia coli as compared to gram positive Staphylococcus aureus. The finding is attributed to the thicker Staphylococcus aureus membrane as compared to thinner membrane of Escherichia coli. It is also found out that a higher silver particle content of the samples results in a stronger antibacterial property.
Hamidreza Farzin, Amiri Mohadese, Samira Kadoughani Sani, Majid Jamshidian Mojaver,
Volume 12, Issue 1 (12-2020)
Abstract
Abstract
Urinary tract infection is one of the most common and common bacterial infections, accounting for a significant proportion of hospital admissions (about 30-40%). Silver nanoparticles work by releasing silver ions against various bacteria. The fact that bacteria are not resistant to nanoparticles is very important and therefore will affect a wide range of bacteria.
Materials and Methods
In this study, 50 specimens of positive cultures with urinary tract infection referred to Imam Reza Hospital Laboratory in Bojnourd were studied. Resistance and susceptibility of the isolates were determined by disk diffusion method. In this study, antibacterial effects of silver nanoparticles were investigated by microdilution method using aqueous extract of Ganoderma leucidum. Vegetative electron microscopy was used to measure the size and shape of silver nanoparticles. In addition, infrared spectroscopy analysis was performed to investigate possible organic compounds involved in the synthesis of nanoparticles.
Results: The highest antibiotic resistance was related to ampicillin (84%). The resulting nanoparticles were 20 to 45 nm in size.
Conclusion:
The produced nanoparticles have antimicrobial activity and can be a good alternative in the treatment of antibiotic resistant infectious diseases.
Babak Sadeghi, Bite Koupaei,
Volume 12, Issue 2 (1-2022)
Abstract
In the present work, we describe the synthesis of silver nanoparticles (Ag-NPs) using seed aqueous extract of Psidium guajava (PG) and its antibacterial activity. UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) were performed to ascertain the formation of Ag-NPs. It was observed that the growths of Ag-NPs are stopped within 35 min of reaction time. The synthesized Ag-NPs were characterized by a peak at 446 nm in the UV–visible spectrum. XRD confirmed the crystalline nature of the nanoparticles of 10-20 nm size. The XRD peaks at 38◦, 44◦, 64◦ and 77◦ can be indexed to the (1 1 1), (2 0 0), (2 2 0) and (3 1 1) Bragg’s reflections of cubic structure of metallic silver, respectively. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of used drugs against bacterial diseases. The results confirmed that the (PG) is a very good eco friendly and nontoxic source for the synthesis of Ag-NPs as compared to the conventional chemical/physical methods.
Volume 19, Issue 3 (5-2017)
Abstract
In this research Kelussia odoratissima Mozaff. leaf extract was used for the green synthesis of silver nanoparticles (AgNPs). At first we compared antioxidant activity of different extracts of K. odoratissima. Then solution containing silver nitrate was treated with the extract which showed high antioxidant activity. Synthesized AgNPs were evaluated by analyzing the excitation of surface plasmon resonance. TEM analysis was also used for nanoparticle characterization. Antibacterial activity of the solution containing AgNPs was measured by microdilution test. Common food contaminant bacteria such as gram-positive (Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes) and gram-negative (Escherichia coli O157: H7, Salmonella enterica and Pseudomonas aeruginosa)were used for the evaluation. The aqueous extract showed the highest antioxidant activity and the solution was used for the green synthesis of AgNPs. The particle diameters were calculated to be 20-40nm with -17 to -19.9 mV zeta potential. The TEM micrographs showed that the AgNPs are nearly spherical in shape and highly monodispersed. MIC of the AgNPs against gram-positive and gram-negative bacteria was between 0.012-0.025 and 0.006-0.012 mg/ml respectively.
Volume 20, Issue 141 (10-2023)
Abstract
Green synthesis plays an important role because of its involvement in unusual syntheses of metal nanoparticles from plant extracts, which have antimicrobial potential. Therefore, green synthesis of nanoparticles from plant extracts is a suitable way to produce nanoparticles. Therefore, the aim of this research was to synthesize Ag/AgCl /TiO2 three-component nanocomposite using Zataria Multiflora plant and evaluate the size and morphology of the produced nanoparticles. For this purpose, synthesis, and characterization of Ag/AgCl/TiO2, a three-component nanocomposite was done using Zataria Multiflora plant extract using UV-Vis, XRD, TEM, and FTIR techniques. Then, the characteristics of nanocomposites were investigated. The results showed that the largest diameter of the non-growth halo was observed in all studied bacteria in the nanocomposite containing 50% color and in the nanocomposite containing 5% (Ag/TiO2mol). The diameter of the non-growth halo increased from 0.5% to 3% in the film containing TiO2/Ag/AgCl nanoparticles in all investigated microorganisms. Also, TEM images showed the uniform loading of Ag/AgCl nanoparticles on the TiO2 surface. Overall, the obtained results showed that Zataria Multiflora plant extract, along with silver and titanium dioxide nanocomposites, has a high potential in producing nanoparticles with high purity, in nanometer sizes, with antimicrobial properties, which has properties in the food industry as a coating and film.
Volume 21, Issue 154 (12-2024)
Abstract
Plant extracts and nanoparticles prepared from them due to their antimicrobial and antioxidant properties can be used to increase the shelf life of meat. In the present study, the biodegradable film of polylactic acid containing silver nanoparticles synthesized from Satureja rechingeri extract on the physicochemical and microbial properties of chicken fillet at refrigerated temperature was investigated. So that the control sample (code 1), chicken fillet coated with biodegradable film of polylactic acid (code 2), chicken fillet coated with biodegradable film of polylactic acid containing Satureja rechingeri extract (code 3) and the Chicken fillet coated with biodegradable polylactic acid film containing silver nanoparticles synthesized from Satureja rechingeri extract (code 4) at 4°C in chemical, microbial and sensory properties at intervals of 0, 3, 7 and 14 The days were examined. The results showed that the mean diameter of the growth inhibition zone against Staphylococcus aureus and Escherichia coli bacteria for Satureja rechingeri extract containing silver nanoparticles was significantly higher than Satureja rechingeri extract (p≤0.05). In all the studied days except the first day, the lowest pH of thiobarbituric acid belonged to sample 4 (p≤0.05). Also, on the third and seventh days, the highest L* color component belonged to sample 4 (p≤0.05). On all the examined days, except on the first day, the lowest population of mesophilic bacteria, psychrophilic bacteria, coliform, Staphylococcus aureus, mold and yeast, and mold and yeast, as well as the highest score of all sensory factors (odor, color, texture, overall acceptance) belonged to sample 4 (p≤0.05).Sample 4 was selected as the superior treatment for higher sensory score and more desirable microbial properties.
Volume 26, Issue 2 (4-2023)
Abstract
The escalating incidence of foodborne diseases caused by pathogenic bacteria presents a substantial global health concern. Microbial spoilage of food not only shortens product shelf life but also increases the risk of foodborne diseases. According to the World Health Organization, one in ten people worldwide falls ill after consuming contaminated food. While foodborne diseases are preventable, the implementation of effective strategies to control and prevent these illnesses remains a critical global challenge. The unique properties of both organic and inorganic nanoparticles have attracted significant attention in the food industry due to their potential to enhance nutritional, safety, and quality attributes of food products. A majority of foodborne infections are attributed to pathogens such as Salmonella, Listeria, Escherichia coli, Clostridium, and Campylobacter. Silver and silver-based compounds have been shown to exhibit potent antimicrobial activity against a broad spectrum of bacteria. The current body of knowledge regarding the application of silver nanoparticles for the elimination of foodborne pathogens is expanding rapidly, providing opportunities to explore their mechanisms of action, benefits, and limitations. This perspective aims to identify novel strategies for reducing the burden of foodborne diseases by critically evaluating the potential of silver nanoparticles. Furthermore, the potential health implications of silver nanoparticles for human consumption will be discussed to inform the development of effective policies for public health.
