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1.
Many methods of synthesizing silver nanoparticles (Ag-NPs) by reducing Ag+ ions using aqueous/organic extracts of various plants have been reported in the past, but the methods are rather slow. In this investigation, silver nanoparticles were quickly synthesized from aqueous silver nitrate through a simple method using leaf extract of a plant—Cynodon dactylon which served as reducing agent, while sunlight acted as a catalyst. The formation of Ag-NPs was indicated by gradual change in colour and pH and confirmed by ultraviolet–visible spectroscopy. The Ag-NPs showed a surface plasmon resonance at 451 nm. Based on the decrease in pH, a possible mechanism of the synthesis of Ag-NPs involving hydroxyl (OH?) ions of polyphenols of the leaf extract is postulated. Ag-NPs having (111) and (200) crystal lattices were confirmed by X-ray diffraction. Scanning electron microscopy revealed the spherical nature of the Ag-NPs, while transmission electron microscopy showed that the nanoparticles were polydispersed with a size range of 8–10 nm. The synthesized Ag-NPs also demonstrated their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhimurium.  相似文献   

2.
The present paper describes about the easy, simple and convenient procedure for the synthesis of silver nanoparticles (Ag-NPs) in aqueous solutions by the reduction of silver nitrate with adrenaline. The surfactant molecules of cetyltrimethylammonium bromide (CTABr) and sodium dodecyl ate (SDS) behaved differently during the reduction of Ag+ ions by adrenaline. The obtained data suggest that the variation of [CTABr] gave a maxima-like curve for rate constant versus [CTABr], while, the values of rate constant decreased with the increase in [SDS]. The addition of surfactant molecules stabilized the Ag-NPs. The UV–Visible spectra were analyzed to deduce the particle size. The calculated sizes of the nanoparticles were further compared by the TEM images. The XRD spectrum confirmed the crystalline nature of silver nanoparticles having the face-centered cubic crystal structure. The edge length of unit cell was found 4.076 Å. The kinetics of formation of Ag-NPs was performed at different concentrations of adrenaline, AgNO3, NaOH and [surfactant]. The values of rate constant were independent on [adrenaline] and [AgNO3]. The increase in [NaOH] increased the rate of agglomeration of silver particles to form Ag-NPs. A linear relationship was obtained for the plot of rate constant versus [NaOH].  相似文献   

3.
The evaluation of cytotoxic and apoptotic activities of silver nanoparticles (Ag-NPs) synthesized by aqueous extract of Prosopis farcta was investigated against lung (A549) and colon (HT-29) cell lines. The cytotoxic activity of nanoparticles was performed using MTT assay, while their apoptotic activity was tested using TUNEL method. The obtained results of MTT showed that the cell viability of A549 was dependent on the nanoparticles concentration and incubation time. Therefore, although the cytotoxic effect increased as the Ag-NPs concentration and incubation time heightened, yet the viability of HT-29 cells seems to be dependent only on the incubation time. The apoptotic results of the nanoparticles showed more than 50% of apoptosis on A549 and HT-29 cell lines, which in this case, HT-29 demonstrated 100% apoptosis at concentrations of more than 400 µg/ml. It seems that Ag-NPs synthesized using P. farcta extract can serve as anti-cancer agent in the treatment many cancers through creating or discovering new drug forms.  相似文献   

4.
In the search for alternative therapy for infections and other ailments, metallic nanoparticles, mainly silver nanoparticles (AgNPs) synthesized through bioengineered sources are extensively explored. Fungal bioactive compounds and their nanoparticles were reported with the potential biomedical application. A medicinal mushroom Ganoderma lucidum was reported as a repository of rich medicinal properties. In the current study, silver nanoparticles were synthesized using the extracts of G. lucidum and its antimicrobial activity was tested against drug-resistant Escherichia coli isolated from the catheter used for urinary tract infection (CAUTI). The GC–MS study of G. lucidum extracts showed the presence of ethyl acetoacetate ethylene acetal with the highest area percentage of 72.2% and retention time (RT 5873). Pyridine-3-ol is the second primary compound with a peak height of 6.44% and a retention time of 2.143. The third compound is l,4-Dioxane-2,3-diol, with an area of 8.09% and RT 5450. Butylated Hydroxy Toluene [BHT] is the fourth major compound with an area of 3.32%, and 9-Cedranone constitutes the fifth position in occupying the area percentage [1.88] and height 1.56%. Pyrrole is the sixth primary compound registering an area size of 0.96% and height 2.06%. The AgNPs synthesized using G. lucidum extract were in size range 23 and 58 nm as per SEM analysis and within the range wavelength 0.556–0.796 nm as per UV–Vis spectral study. FTIR Spectroscopy and X-ray diffraction analysis (XRD) were made to characterize the formed nanoparticles. The AgNPs synthesized effectively inhibited the growth of E. coli isolated from catheter-associated urinary tract infection and showed resistance to many drugs. The antioxidant potential of the synthesized nanoparticles assessed using DPPH radical scavenging activity, EC50 (µg/ml), and ARP data showed that the prepared nanoparticles were more potent in free radical scavenging activity than the standard quercetin. The cytotoxicity effect of Ag-NPs on breast cancer cell line- MDA-MB-231 confirmed its anticancer potential. The half-maximal inhibitory concentration (IC50) of Ag-NPs to inhibit 50% of the tumor was 9.2 g/mL. The synthesized GL-AgNPs was exhibited a multifocal biomedical potential.  相似文献   

5.
Kim HR  Kim MJ  Lee SY  Oh SM  Chung KH 《Mutation research》2011,726(2):129-135
Many classes of silver nanoparticles (Ag-NPs) have been synthesized and widely applied, but the genotoxicity of Ag-NPs and the factors leading to genotoxicity remain unknown. Therefore, the purpose of this study is to elucidate the genotoxic effects of Ag-NPs in lung and the role of oxidative stress on the genotoxic effects of Ag-NPs. For this, Ag-NPs were completely dispersed in medium by sonication and filtration. The Ag-NPs dispersed in medium were 43-260nm in size. We observed distinct uptake of Ag-NPs into BEAS-2B cells. The Ag-NPs aggregates were wrapped with an endocytic vesicle within the cytoplasm and nucleus of BEAS-2B cells. In the comet assay and micronucleus (MN) assay for BEAS-2B cells, Ag-NPs stimulated DNA breakage and MN formation in a dose-dependent manner. The genotoxic effect of Ag-NPs was partially blocked by scavengers. In particular, of the scavengers tested, superoxide dismutase most significantly blocked the genotoxic effects in both the cytokinesis-block MN assay and the comet assay. In the modified comet assay, Ag-NPs induced a significant increase in oxidative DNA damage. Furthermore, in the oxidative stress assay, Ag-NPs significantly increased the reactive oxygen radicals. These results suggest that Ag-NPs have genotoxic effects in BEAS-2B cells and that oxidative stress stimulated by Ag-NPs may be an important factor in their genotoxic effects.  相似文献   

6.
The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureus ATCC 6538P were investigated in this study. The experiment results showed the minimum bactericidal concentration (MBC) of Ag-NPs to S. aureus was 20 μg/ml. Moreover, when bacteria cells were exposed to 50 μg/ml Ag-NPs for 6 h, the cell DNA was condensed to a tension state and could have lost their replicating abilities. When S. aureus cells were exposed to 50 μg/ml Ag-NPs for 12 h, the cell wall was breakdown, resulting in the release of the cellular contents into the surrounding environments, and finally became collapsed. And Ag-NPs could reduce the enzymatic activity of respiratory chain dehydrogenase. Furthermore, the proteomic analysis showed that the expression abundance of some proteins was changed in the treated bacterial cell with Ag-NPs, formate acetyltransferase increased 5.3-fold in expression abundance, aerobic glycerol-3-phosphate dehydrogenase decreased 6.5-fold, ABC transporter ATP-binding protein decreased 6.2-fold, and recombinase A protein decreased 4.9-fold.  相似文献   

7.
Silver nanoparticles (Ag-NPs) are known to have inhibitory and fungicidal effects. Resistance against fungal infection has emerged as a major health problem in recent years, which needs great and immediate concern. Here, we report the extracellular biological synthesis of silver nanoparticles through a simple green route approach using a marine mangrove (Rhizophora mucronata) and silver nitrate. Aqueous extract of marine mangrove helped in reduction and was used as capping agent in biological synthesis. Nanoparticles were characterized using microscopy and spectroscopy techniques such as HRTEM, UV–Vis absorption spectroscopy and FTIR spectroscopy. X-ray diffraction analysis showed that the nanoparticles had face centered cubic structure with crystalline nature. FTIR spectroscopy showed the presence of different functional groups, such as hydroxyl and carbonyl, involved in the synthesis of nanoparticles. The antifungal activity of fluconazole and itraconazole was enhanced against the tested pathogenic fungi in the presence of Ag-NP and confirmed from increase in fold area of inhibition. This environmentally friendly method of biological synthesis can be easily integrated for various medical applications.  相似文献   

8.
As part of the desire to save the environment through “green” chemistry practices, we herein report an environmentally benign synthesis of silver nanoparticles (Ag-NPs) using cellulose extracted from an environmentally problematic aquatic weed, water hyacinth (WH), as both reducing and capping agent in an aqueous medium. By varying the pH of the solution and reaction time, the temporal evolutions of the optical and morphological properties of the as-synthesised Ag-NPs were investigated. The as-synthesised cellulose capped silver nanoparticles (C–Ag-NPs) were characterised using Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The maximum surface plasmon resonance (SPR) peak decreased as the pH increased indicating that an increase in the pH of the solution favoured the formation of smaller particles. In addition, instantaneous change in the colour of the solution from colourless to brown within 5 min at pH 11 showed that the rate of reduction is faster at this pH compared to those at lower pH. The TEM micrographs showed that the materials are small, highly monodispersed and spherical in shape. The average particle mean diameters were calculated to be 5.69 ± 5.89 nm, 4.53 ± 1.36 nm and 2.68 ± 0.69 nm nm at pH 4, 8 and 11 respectively. The HRTEM confirmed the crystallinity of the material while the FTIR spectra confirmed the capping of the as-synthesised Ag-NPs by the cellulose. It has been shown therefore that based on this synthetic method, this aquatic plant can be used to the advantage of mankind.  相似文献   

9.
Central composite design was chosen to determine the combined effects of four process variables (AgNO3 concentration, incubation period, pH level and inoculum size) on the extracellular biosynthesis of silver nanoparticles (AgNPs) by Streptomyces viridochromogenes. Statistical analysis of the results showed that incubation period, initial pH level and inoculum size had significant effects (P<0.05) on the biosynthesis of silver nanoparticles at their individual level. The maximum biosynthesis of silver nanoparticles was achieved at a concentration of 0.5% (v/v) of 1 mM AgNO3, incubation period of 96 h, initial pH of 9 and inoculum size of 2% (v/v). After optimization, the biosynthesis of silver nanoparticles was improved by approximately 5-fold as compared to that of the unoptimized conditions. The synthetic process of silver nanoparticle generation using the reduction of aqueous Ag+ ion by the culture supernatants of S. viridochromogenes was quite fast, and silver nanoparticles were formed immediately by the addition of AgNO3 solution (1 mM) to the cell-free supernatant. Initial characterization of silver nanoparticles was performed by visual observation of color change from yellow to intense brown color. UV-visible spectrophotometry for measuring surface plasmon resonance showed a single absorption peak at 400 nm, which confirmed the presence of silver nanoparticles. Fourier Transform Infrared Spectroscopy analysis provided evidence for proteins as possible reducing and capping agents for stabilizing the nanoparticles. Transmission Electron Microscopy revealed the extracellular formation of spherical silver nanoparticles in the size range of 2.15–7.27 nm. Compared to the cell-free supernatant, the biosynthesized AgNPs revealed superior antimicrobial activity against Gram-negative, Gram-positive bacterial strains and Candida albicans.  相似文献   

10.
Uptake of horseradish peroxidase (HRP) was quantified in the unicellular eukaryote Paramecium aurelia. About 80% of the total HRP accumulated within 20 min entered the cells via a fluid phase pathway as demonstrated measuring the HRP internalization in the presence of yeast mannan. The rate of HRP accumulation was concentration-dependent and was found to be linear over the range of 50–500 μg HRP per ml of the extracellular medium. During the first 10 min of exposure to HRP, the mannan-uninhibitable uptake was found to reach 1.2–1.65 ng HRP per mg protein (depending on the concentration of the marker in the medium), which corresponds to 0.68 fl per cell/min. Accumulation of HRP reached a plateau within the next 10–15 min and its intracellular uptake was 2–2.55 ng HRP per mg protein. When the phagocytic activity of the cells was blocked with 1-propranolol, the amount of cell-accumulated HRP was 1.8–2.1-fold higher than in the control and the rate of the marker uptake within the first 10 min of incubation reached 1.114 fl per cell/min.  相似文献   

11.
By taking silver nanoparticles (Ag-NPs) as plasmon resonance scattering (PRS) indicator considering that Ag-NPs have strong plasmon resonance light scattering signals corresponding to their plasmon resonance absorption (PRA), we propose a label-free visual immunoassay on the solid support of glass slides. Our investigations showed that Ag-NPs could be adsorbed on the surface of glass slides where immunoreactions between a previously immobilized antigen and its antibody have occurred if the glass slides were immersed in an Ag-NP suspension whose pH value has been carefully adjusted. The optimal pH of the Ag-NP suspension depends on the nature of previously immobilized antigen and its antibody. It was found that the adsorption of negative-charged Ag-NPs on the surface of glass slides depends only on the content of antibody under optimal conditions. With a common spectrofluorometer to measure the PRS signals of the Ag-NPs adsorbed on the surface, we could detect antibody in the range of 10 to 160 ng ml−1. If a white light-emitting diode (LED) torch is employed to illuminate the glass slides, we can make visual detection of the antibody by the naked eye.  相似文献   

12.
Leishmaniasis is a group of infectious and noncontagious severe parasitic diseases, caused by protozoans of the Leishmania genus. Natural products characterize a rich source of prospective chemical entities for the development of new effective drugs for neglected diseases. Scientific evaluation of medicinal plants has made it possible to use some metabolites from flavonoids and polyphenols compounds for the treatment of parasitic diseases. Therefore, we aimed in the present study to evaluate the protective effect of silver nanoparticles (Ag-NPs) biosynthesized using Fig and Olive extracts (NFO) against Cutaneous leishmaniasis in female Balb/c mice. A total of 70 mice were used and divided into seven groups. Treatment was initiated when local lesions were apparent, we found that Fig and Olive extracts were found to be a good source for the synthesis of (Ag-NPs), their formation was confirmed by color change and stability in solution. Nanoparticles biosynthesized using Fig and Olive extracts induced a reduction in the average size of cutaneous leishmaniasis lesions compared with the untreated mice. Moreover, nanoparticles treatment decreased oxidative stress (LPO, NO), down-regulation gene expression levels (TNF-α, IL-1β, and BAX), and this antileishmanial activity of nanoparticles was associated with enhanced antioxidant enzyme activities. In addition, histopathological evaluation proved the antileishmanial activity of nanoparticles compared with the positive control.Therefore, we aimed in the present study to evaluate the protective effect of silver nanoparticles biosynthesized using Fig and Olive extracts against cutaneous lesions induced by Leishmania major infection through their anti-inflammatory, antioxidant activities, and faster clinical efficacy than standard pentavalent antimonial treatment.  相似文献   

13.
The design and development of a screen printed carbon electrode (SPCE) on a polyvinyl chloride substrate as a disposable sensor is described. Six configurations were designed on silk screen frames. The SPCEs were printed with four inks: silver ink as the conducting track, carbon ink as the working and counter electrodes, silver/silver chloride ink as the reference electrode and insulating ink as the insulator layer. Selection of the best configuration was done by comparing slopes from the calibration plots generated by the cyclic voltammograms at 10, 20 and 30 mM K(3)Fe(CN)(6) for each configuration. The electrodes with similar configurations gave similar slopes. The 5th configuration was the best electrode that gave the highest slope. Modifying the best SPCE configuration for use as a biosensor, horseradish peroxidase (HRP) was selected as a biomaterial bound with gold nanoparticles (AuNP) in the matrix of chitosan (HRP/AuNP/CHIT). Biosensors of HRP/SPCE, HRP/CHIT/SPCE and HRP/AuNP/CHIT/SPCE were used in the amperometric detection of H(2)O(2) in a solution of 0.1M citrate buffer, pH 6.5, by applying a potential of -0.4V at the working electrode. All the biosensors showed an immediate response to H(2)O(2). The effect of HRP/AuNP incorporated with CHIT (HRP/AuNP/CHIT/SPCE) yielded the highest performance. The amperometric response of HRP/AuNP/CHIT/SPCE retained over 95% of the initial current of the 1st day up to 30 days of storage at 4 degrees C. The biosensor showed a linear range of 0.01-11.3mM H(2)O(2), with a detection limit of 0.65 microM H(2)O(2) (S/N=3). The low detection limit, long storage life and wide linear range of this biosensor make it advantageous in many applications, including bioreactors and biosensors.  相似文献   

14.
15.
In this work, we investigate silver (Ag) nanoparticle-related plasmonic effect on light absorption in Si substrate. Ag nanoparticles (Ag-NPs) deposited on top of Si were used to capture and couple incident light into these structures by forward scattering. We demonstrate that we can control nanoparticle size and shape while varying deposition time and annealing parameters. By the increase of the total time of the reaction process, morphology of Ag-NPs evolutes affecting the number and the width of surface plasmon resonance peaks, whereas for changed annealing parameters (temperature and time), the effect is more pronounced on the broadening and the position of peaks. Specific morphology of Ag-NPs can exhibit an interesting enhancement of optical properties which enables plasmon-related application in photovoltaic solar cells.  相似文献   

16.
Aims:  We report extracellular synthesis of silver nanoparticles (Ag-NPs) from Phoma glomerata and its efficacy against Escherichia coli , Staphylococcus aureus and Pseudomonas aeruginosa . The bacteria exhibiting resistance to various antibiotics showed remarkable sensitivity, when used in combination of antibiotics and Ag-NPs.
Methods and Results:  Biosynthesis of Ag-NPs was carried out by challenging the fungal cell filtrate with 1 mmol l−1 silver nitrate. The Ag-NPs were characterized with the help of UV–Visible spectrophotometer and Fourier transform infrared spectroscopy. Scanning electron microscopy was carried out to detect the size of Ag-NPs. Evaluation of the combined effect(s) was studied by disc diffusion method against E. coli , Staph. aureus and Ps. aeruginosa .
Conclusions:  The biosynthesis route seems to be eco-friendly and easy to scale up the process. Thus, these Ag-NPs may prove as a better candidate for drugs and can potentially eliminate the problem of chemical agents because of their biogenic nature.
Significance and Impact of the Study:  The bacterial resistance against antibiotics has been increasing with alarming rate. To overcome this problem, there is a pressing need to develop bactericidal agents. Ag-NPs may prove to be an answer to drug-resistant bacteria.  相似文献   

17.
Saccharomyces cerevisiae mannan inhibits the pinocytosis of horseradish peroxidase (HRP) by resident, thioglycollate-,proteose peptone-, and Corynebacterium parvum-elicited macrophages from 30 to 70% when 1 mg/ml HRP is used, and 65 to 87% when 250 micrograms/ml HRP is used. In contrast, HRP uptake by J774 cells, a macrophage cell line reported to have little mannose receptor activity, is inhibited only about 25% by mannan. HRP uptake by resident and thioglycollate-elicited (thio) macrophages is also inhibited 34 and 66% by addition of EGTA to the medium and 55 and 79% by trypsin treatment of the macrophages, respectively. The inhibitory effect of EGTA can be reversed by 1 mM excess Ca2+. High extracellular concentrations of Ca2+, in the range of 10-20 mM, however, inhibit pinocytosis in resident macrophages by about 50%. Sucrose uptake by resident macrophages is not appreciably affected by mannan. These results support the hypothesis that HRP uptake is mediated by the macrophage mannose/N-acetylglucosamine receptor. PMA stimulates fluid-phase pinocytosis of HRP by thio macrophages but does not affect receptor-mediated uptake of HRP, while the combination of adenosine, homocysteine, and erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) selectively inhibits bulk-phase uptake by thio macrophages.  相似文献   

18.
BackgroundThe present work aimed to detect the toxicological effects of green synthesized silver nanoparticles (Ag-NPs) by using Moringa Oleifera leaves extract on hematological and biochemical parameters of Oreochromis niloticus.MethodsAdult fish were exposed to two sublethal concentrations (1.95 and 3.9 ppm) of Ag-NPs against sodium selenite (0.1 ppm) and biosynthesized selenium nanoparticles (Se-NPs); 0.1 ppm; protection role for 2 and 4 weeks. Hematological parameters; erythrocyte count (RBCs), hemoglobin content (Hb), haematocrit value (Hct), mean corpuscular volume (MCV), Mean Corpuscular Hemoglobin Concentration (MCHC), leucocytes (WBCs), with differential count Micronucleus (MN) and alerted cells and biochemical parameters; aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) enzyme activities, serum protein (total protein, albumin and globulin) concentration, urea, creatinine, glucose, cholesterol (Cho) and triglyceride (Tg) were detected.ResultsThe present investigation showed that Ag-NPs in different doses led to a significant reduction (p < 0.05) in RBCs, Hb, Hct, MCV, WBCs, LYM and serum proteins concentration. However, MCHC, MN, alerted cells, NEUT, AST, ALT, ALP enzyme activities, urea, creatinine, glucose, Cho and Tg showed a significant increases (p < 0.05) when compared with control group. Sodium selenite (Se) and biosynthesized selenium nanoparticles (Se-NPs) play an optimistic role in detoxification of Ag-NPs toxicity.ConclusionThe results suggest the negative impact of Ag-NPs on hematology and biochemical parameters of fish. Moreover, Se-NPs showed a full improvement of hematological and biochemical parameters more than that of sodium selenite in elimination of Ag-NPs toxicity.  相似文献   

19.
Current study investigated the nematicidal activity of leaf extracts of Conyza dioscoridis, Melia azedarach, and Moringa oleifera that were prepared as silver nanoparticles (Ag-NP). The characterisation and size confirmation of the Ag-NP were done by UV–vis spectrophotometry and the scanning electron microscopy (SEM). The phytochemical contents of crude extracts and the nano formulations were analysed using gas chromatography-mass spectroscopy (GC-MS). Results revealed that silver nanoparticles of C. dioscoridis extractives had great nematicidal activity against the 2nd stage juvenile (J2) and eggs of Meloidogyne incognita. Also, the Ag-NP showed similar nematicidal effect to the reference nematicide; rugby. The GC-MS analysis revealed the increase of certain metabolites due to the formulation of the Ag-NPs. Aromadendrene, 1-hydroxy-1,7-dimethyl-4-isopropyl-2,7-cyclodecdiene, 6-epi-shyobunol, 4-hexylacetophenone, β-isocomene, caryophyllene, β- and α-selinene, α-cadinol, berkheyaradulen, and bis-(2-ethylhexyl)phthalate were increased more than 2.5-folds in the Ag-NP compared the extract. Therefore, the green synthesis of metal nanoparticles might be a safe, effective and affordable nematicide alternatives.  相似文献   

20.
《Process Biochemistry》2010,45(7):1065-1071
In this paper we have reported the green synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles by reduction of silver nitrate and chloroauric acid solutions, respectively, using fruit extract of Tanacetum vulgare; commonly found plant in Finland. The process for the synthesis of AgNPs and AuNPs is rapid, novel and ecofriendly. Formation of the AgNPs and AuNPs were confirmed by surface plasmon spectra using UV–Vis spectrophotometer and absorbance peaks at 452 and 546 nm. Different tansy fruit extract concentration (TFE), silver and gold ion concentration, temperature and contact times were experimented in the synthesis of AgNPs and AuNPs. The properties of prepared nanoparticles were characterized by TEM, XRD, EDX and FTIR. Finally zeta potential values at various pH were analyzed along with corresponding SPR spectra.  相似文献   

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