Different Concentrations Of Silver Nanoparticles Research Articles

Evaluation of Anticancer activity of Silver Nanoparticles on the A549 Human lung carcinoma cell lines through Alamar Blue Assay.

Silver nanoparticles have been widely studied to possess antimicrobial as well as anticancer activity, and have found its applications in various fields including pharmaceutical industry, diagnostics, drug delivery, food industry, and others. For this purpose, several cell proliferation assays are widely used for the evaluation of anticancer activity of synthetic compounds as well as natural plant extracts. In general, a compound is said to possess an anticancer activity if it prevents the cancer cells to grow and divide actively, and indirectly activates the generic program of cell death. In this protocol, Alamar blue and MTT assay are described for the analysis of metabolic function and health of the cell. These procedures are generally used for the endpoint analysis. A549 cells are seeded in a 96-well plate, and after the adherence of the cells, they are treated with different concentrations of silver nanoparticles. Followed by 24 h of incubation, colorimetric dyes are added to the wells, and the absorbance is recorded to quantify the percentage cytotoxicity in the sample wells.

Antimicrobial Effect of Diode Laser and Biosynthesis Silver Nanoparticles on Escherichia Coli in Vitro

The laser and nanoparticles representing the concourse of biological science with physical science and considering modern method that used as an antibacterial instead of conventional antibiotics. The present study is an attempt to illustrate how the use of laser or silver nanoparticles each of them individually, as an antibacterial agent against Escherichia coli (E. coli) as well as study the effective result from theabsorption of Diode laser energy by these nanoparticles to kill or inhibition bacterial growth. The silver nanoparticles (AgNPs) are prepared by biological method E. coli were isolated and identified by use MacConkey agar and biochemical tests. Nanoparticles are tested against E. coli cultured on Muller Hinton agar but Diode laser or laser with nanoparticles are tested against E. coli that cultured in Nutrient broth. E. coli are irradiating by Diode laser with different times. Different concentrations of silver nanoparticles have been employed for killing and inhibition bacterial growth. Results showed E. coli was effected by nanoparticles (mainly highest concentration of nanoparticles) also detected that decrease bacterial availability with increase time of exposure to Diode laser

English

English

Synthesis, characterization and antimicrobial study of poly (methyl methacrylate)/Ag nanocomposites

The main aim of this study is to investigate the effect of Ag loading on UV absorption and antimicrobial behavior of Poly (methyl methacrylate)/silver nanocomposites. In this research, silver nanoparticles were incorporated in Poly (methyl methacrylate) (PMMA) via reduction method using dimethyl formamide as a solvent as well as reducing agent and Tween-80 as a stabilizer. The morphological study was carried out using FESEM and TEM. The presence of Ag nanoparticles confirmed through EDX spectroscopy. The study reveals that the particles are of spherical shape and are of nanometer size. The UV absorption spectra of silver nanocomposites were determined by UV absorption spectrophotometer. Red shift in absorption maxima was observed on increasing the concentration of Ag nanoparticles in polymer matrix. The antibacterial and antifungal activities of different concentration of silver nanoparticles in polymer composites were investigated against Pseudomonas aeruginosa (Gram-negative), Staphylococcus aureus (Gram-positive) bacteriae and pathogenic fungus Cryptococcus neoformans by well diffusion method. Zone of inhibition method was used to assess the antimicrobial action of nanocomposites.

Green synthesis of silver nanoparticles from Azadirachta indica andocimum sanctum and Their antimicrobial efficacy

Nanoparticles are used immensely due to its small size and physical properties which are reportedly shown to change the performance of any other material which is in contact with these tiny particles. These particles can be prepared easily by different chemical, physical and biological approaches. But the biological method is the most efficient approach for the preparation of nanoparticles because it is eco friendly and less time consuming. The leaves extracts of Azadirachta indica and Ocimum sanctum acts as a capping agent, reducing agents, and posses antibacterial activities and healing properties. In this study, simple and rapid approach was applied for the green synthesis of silver nanoparticles from Azadirachta indica(neem) and Ocimum sanctum (Tulsi) leaves extracts. The biosynthesized silver nanoparticles were characterized using UV – Visible Spectroscopy, XRD, and SEM. The size of biosynthesized silver nanoparticles was found to be within the range of 20-60 nm. To identify the compounds for the reduction of silver ions, the functional groups present in plant extract were investigated by FTIR. The nanoparticles were tested for their antibacterial potential against drug – resistant bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii and against pathogenic fungus, Rhizopus oryzae, and Aspergillus Niger. It was found that the biosynthesized nanoparticles had an inhibitory effect towards these microbes. The toxicity analysis of silver nanoparticles was determined by treating the Moong seeds (V. radiata) with different concentrations of silver nanoparticles. The results showed that 25% of silver nanoparticles solution had the better effect towards the seed germination and oxidative stress enzyme activity.

The Effect of Silver Nano Particles on Candida Albicans and Streptococcus Mutans in Denture Acrylic Resins

Introduction: Denture stomatitis is a common complication in patients wearing dentures and preventing the proliferation of related microorganisms and their induced infections is noteworthy. The aim of the present study was to assess the antimicrobial effect of acrylic resins containing various concentrations of silver nanoparticles, on Candida albicans and Streptococcus mutans. Materials and Methods: In this in vitro study, the effect of four different concentrations of silver nanoparticles in 160 acrylic samples (10mm *4mm) on standard and hospital isolated strains of two different microorganisms were investigated. The samples were soaked (containing silver nanoparticles and control) in bacterial suspension and the antimicrobial tests were performed after 0, 1, 6 and 24 hours. Mean and standard deviation were used to describe the data and one-way variance analysis test was performed to compare groups. Results: Results have shown that in concentration of 2.5% the highest mean difference for standard S. mutans, after 24h of exposure was 540.0±14.4 (P<0.001), while in 5% ,this value for standard C.albicans after 6h of exposure was 953.0±87.0 (P<0.001). However in concentration of 10% the highest mean difference of 1000.0±24.9 in standard C.albicans after an exposure period of 24h (p<0.001) was observed, which was indicative of the significant effect of the highest concentration of silver nanoparticles. Conclusion: 1. in acrylic resins, increase in silver nanoparticle concentration leads to a greater antimicrobial effect. 2. Acrylic resins containing silver nanoparticles have a stronger antimicrobial property on standard C.albicans and generally less effect on hospital isolated strains. 3. The longer time elapsed after exposure of bacterial suspension with acrylic resins containing silver nanoparticles, the less the residual antimicrobial effect.

In vitro reduction of Streptococcus mutans biofilm on silver nanoparticle-modified composite resin

Currently, new methods to reduce biofilm formation on biomaterials are very studied, for example the use of silver nanoparticles, which were bactericidal. However, there are few studies investigating the benefits of these particles in dental restorative materials. Objective:This study aimed to compare in vitro the Streptococcus mutansbiofilm formation on conventional light-cured composite resin with that on experimental light-cured composite resin, modified with silver nanoparticles. Material and methods: Discs were produced with either conventional resin (control group) and resin modified with different concentrations of silver nanoparticles, 0.1%, 0.3% and 0.6 % wt. (groups 1, 2 and 3, respectively). The samples were incubated in bacterial suspension (S. mutans) enriched with 20% sucrose to promote biofilm growth on the surfaces. Incubation times were 1, 4 and 7 days. After each period, adherent biofilms were disaggregated by ultrasound. Then, the numbers of viable cells recovered from the biofilms were counted through the serial dilution method. A morphological analysis of biofilm was also performed by Scanning Electron Microscopy. The data were subjected to Anova and Tukey’s test (α = 0.05). Results: The number of viable cells was statistically lower in groups 2 and 3 than in group 1 and control group, after the three incubation periods, without statistical difference between groups 2 and 3. The number of viable cells was statistically lower in group 1 than in control group, after 4 and 7 days of incubation. Conclusion:Resins modified with silver presented reduction of S. mutans biofilm on their surfaces, according to the conditions of this study.

Silver nanoparticles and electroporation: Their combinational effect on Leishmania major.

Leishmaniasis is an emerging and uncontrolled disease. The use of routine drugs has been limited due to proven side effects and drug resistance. Interestingly, novel approaches such as nanotechnology have been applied as a therapeutic modality. Silver nanoparticles have shown antileishmanial effects but because of their nonspecific and toxic effects on normal cells, their use has been limited. On the other hand, it has been demonstrated that electric pulses induce electropores on cell membranes resulting in higher entrance of certain molecules into cells. There is a hypothesis proposing that use of electroporation and silver nanoparticles simultaneously can induce greater accumulation of particles in infected cells, besides higher toxicity. In this study, after applying electric pulses with different concentrations of silver nanoparticles (SNPs), cell survival rate was determined by standard viability assays. On the basis of these data, 2 μg/ml of SNPs and 700 V/cm with 100 μs duration of electroporation were selected as the non-lethal condition. Promastigotes and infected macrophage cells received both treatments and the survival percentage and Infection Index were calculated. In parasites and cells receiving both treatments, higher toxicity was observed in comparison to each treatment given individually, showing a synergic effect on promastigotes. Therefore, application of electric pulses could overcome limitations in using the antileishmanial properties of silver nanoparticles.

Nonlinear optical characterization of the Ag nanoparticles doped in polyvinyl alcohol films

The effect of silver nanoparticles doped in polyvinyl alcohol (PVA) on the nonlinear optical properties of composite films is studied experimentally. Samples are PVA films of 0.14 mm thickness doped with different concentrations of silver nanoparticles. Nonlinear optical properties of doped polymer films are studied experimentally employing Z-scan techniques. Experiments are performed using the second harmonic of a continuous Nd-Yag laser beam at 532 nm wavelength and 45 mW power. The effect of nonlinear refractive index of samples is obtained by measuring the profile of propagated beam through the samples and their nonlinear refractive index is found to be negative. The nonlinear absorption coefficient is calculated using open aperture Z-scan data while its nonlinear refractive index is measured using the closed aperture Z-scan data, leads to measuring the third order susceptibility |χ(3)|. Real and imaginary parts of the third-order nonlinear optical susceptibility |χ(3)| are decrease with increasing the concentration of Ag nanoparticles in the films. The values of thermo-optic coefficient are determined at different concentrations of silver nanoparticles for samples.

The MIC and MBC of Silver Nanoparticles against Enterococcus faecalis - A Facultative Anaerobe

Aim: To determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of silver nanoparticles against Enterococcus faecalis (E.faecalis). Methodology: The antimicrobial efficacy of the silver nanoparticles was determined by the standard methods of Clinical and Laboratory Standards Institute (CLSI). Different concentrations of silver nanoparticles were prepared, and MIC was calculated by tube macro dilution method. The MBC was determined by the lowest concentration that kills 99.9% of the initial bacterial population. The data was analyzed by non-parametric test of Kruskal-Wallis using SPSS software package (version 17). Results: The MIC and MBC of silver nanoparticles against E. faecalis was found to be optimum at 5 mg/ml. Conclusion: The result obtained from this study shows that silver nanoparticles have potential bactericidal effects against E. faecalis at a concentration of 5 mg/ml. Silver nanoparticles can be incorporated in the root canal medicaments, sealers and irrigants, as it possess potent antimicrobial efficacy against E. faecalis. Significance and impact of study: The antimicrobial property of silver nano particles against E.faecalis can be used clinically as an alternate to various other intra canal medicaments as irrigants.

The effects of silver nanoparticles on antimicrobial activity of ProRoot mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM).

BackgroundAlthough, mineral trioxide aggregate (MTA) and new experimental cement (CEM) are good root filling cements, but had no or low antimicrobial activities. The aim of this study was to evaluate the effects of addition of silver nanoparticles (SNP) to these two cements on antimicrobial effects against five most dental infection related microorganisms.Material and MethodsTwo suspensions of 100 and 200 ppm of SNP were prepared and 180 μl of microbial suspension with 1.5 × 108 CFU/ml of each respected microorganisms were re-suspended in deionized water or each of SNP suspensions. After that, 60 μg of MTA and CEM were added to each tube. In one tube, the mixture of all above mentioned microorganisms were added as a source of microorganism. Colonies were counted after 0, 24, 48, 72 and 96 hours intervals of incubation at 35°C on blood agar for evaluation of antimicrobial efficacy.ResultsMTA and CEM had antibacterial activities on all microorganisms’ strains except for Enterococcus faecalis and mixture group. MTA had better antibacterial activity than CEM but the difference was not significant (p<0.05). The combination of SNP with two cements resulted in significantly higher antimicrobial activities (p<0.05). Also, there was no statistically significant difference between two SNP concentrations (p>0.05).ConclusionsMixture of MTA and CEM with different concentrations of SNP significantly increased the antibacterial activity. Key words:Mineral trioxide aggregate, calcium-enriched mixture, silver nanoparticle, antimicrobial activity.

Effect of silver nanoparticles on maturation of rabbit’s oocytes co-cultured with granulosa cells in vitro

Silver nanoparticles are widely used in different fields of medicine despite the lack of information on their influence on animal’s reproductive system, mammalian gametes and embryos. We investigated the effect of different concentrations of silver nanoparticles (0, 0.01, 0.1, 1 and 10 µg/mL) on maturation of rabbit’s oocytes co-culture with granulosa cells in vitro. For this purpose, we synthesized small (11.28±0.32 nm) sphe­rical silver nanoparticles with different composite agents: polyvinylpyrrolidone and bovine serum albumin. Our results have shown that silver nanoparticles at the concentration of 10 µg/ml inhibited granulosa cells proliferation, but did not influence the oocytes maturation to metaphase-2. The loss of granulosa cells viability was confirmed by the release of calcium and lactate dehydrogenase in the culture medium. Analysis of the data showed that silver nanoparticles in concentration of 0–10 µg/mL did not influence on progesterone and cholesterol concentration in culture medium. We have hypothesized that less toxic effect of silver nanoparticles on oocytes is caused by the presence of zona pellucida with different mechanisms of cellular uptake. Keywords: silver nanoparticles, oocytes, granulosa cells, rabbits.

Size-dependent nonlinear optical properties and thermal lens in silver nanoparticles

We have investigated the nonlinear response of the silver nanoparticle samples in a low-power regime of electromagnetic field based on nonlocal thermo-optic models. In this work, the experimental investigation of the thermo-optic nonlinear response of Ag colloids containing different size of silver nanoparticles is reported. The colloidal nanoparticle samples were synthesized by nanosecond pulsed laser ablation of Ag bulk in acetone. The sample containing Ag was characterized by linear absorption spectroscopy and transmission electron microscopy. Using the z-scan technique, the behavior of thermal nonlinear refractive index of colloid was studied at different concentrations of silver nanoparticles. Observation of asymmetrical configurations of the z-scan data indicates that nonlinear refraction occurring in the Ag samples is related to the thermo-optical process. The optical limiting here is due to nonlinear refraction of the samples arising from thermal lens formation under low-power CW excitation. When the laser power is low, the self-defocusing effect is mainly dominated by surface plasmon resonance effect. Results show that with increasing concentration of nanoparticles in acetone, the nonlinear refractive index increases while the threshold power of optical limiting decreases.

Optical and dielectric properties of ion beam irradiated Ag/polymethyl methacrylate nanocomposites.

Changes in the dielectric, optical, structural and thermal properties of PMMA/silver nanocomposites of different concentrations of silver nanoparticles (5%, 10%, 15%) due to swift heavy ion irradiation were studied by means of impedance gain phase analyzer, UV-visible spectroscopy, X-ray diffraction and differential scanning calorimetry. Samples were irradiated with 120 MeV Si-ions at fluences of 1 x 10(11), 1 x 10(12) ions/cm2. Dependence of dielectric properties on frequency, ion beam fluence and filler concentration was studied. The results revealed the enhancement in dielectric properties after dopping nanoparticles and also upon irradiation. Optical properties like band gap was estimated for pure polymer and nanocomposite films from their optical absorption spectra in the wavelength region 200-800 nm. It was found that the band gap value shifted to lower energy (from 4.58 eV to 3.21 eV) on doping with silver nanoparticles. Differential scanning calorimetry analysis revealed a decrease in the glass transition temperature upon irradiation, which may be attributed to scissioning of polymer chain due to ion beam irradiation which is also confirmed with XRD analysis.

Optical properties of Er3+–Ag co-doped ZnO nanocrystals prepared by combustions method

The Er3+–Ag co-doped ZnO nanocrystals have been synthesized by citric acid-assisted combustions method. The effect of different concentration of silver nanoparticles (NPs) on Er3+ doped ZnO nanocrystals and the optical behaviors are explored. The nanocrystals were characterized by X-ray diffractions, scanning electron microscopy, UV–Vis–NIR absorption spectra, X-ray photoelectron spectroscopy, and photoluminescence, respectively. The luminous intensity of Er3+ doped ZnO nanocrystals was significantly influenced by the concentration of silver NPs. A large enhancement in up-conversion intensity has been observed when the concentration of silver NPs was 0.10 mol%. The effect of localized surface plasmon resonance of silver NPs and the energy transfer between the silver NPs and Er3+ ions (2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2) are discussed as the sources of enhancement or quenching.

Effect of silver nanoparticle embedment on the frequency dispersive conductivity and electrical relaxation dynamics in dodecylbenzenesulfonic acid-doped polyaniline

The present work aims at studying electrical relaxations in silver–polyaniline nanocomposites using dielectric spectroscopy. The nanocomposites of dodecylbenzenesulfonic acid-doped polyaniline (PANI) with different concentrations of silver nanoparticles (~6–12 nm) are synthesized by simple wet-chemical route. The temperature dependence of dc conductivity in all the samples follows three-dimensional variable range-hopping conduction mechanism. The loss factor, after having subtracted the dc contribution, shows a relaxation peak which simultaneously attributes to the frequency dispersion in conductivity spectra. The observed dielectric relaxation is well fitted by the Havriliak–Negami function, and the fitting parameters are determined. The temperature dependence of characteristic relaxation frequency and dc conductivity is in line with each other and bear a resemblance to the origin of dc transport and dielectric relaxation in these systems. The temperature behavior of the relaxation strength confirms that an exclusive hopping conduction of polarons in the disordered PANI matrix can be considered as the origin of the observed electrical properties of the systems. Further, the self-similar behavior of the real part of normalized ac conductivity, within the measured temperature range, also confirms the above inferences. The variation of frequency exponent with temperature suggests that ac conduction is due to the correlated barrier hopping of polarons which strongly affected by the dispersion of silver nanoparticles within the PANI matrix.

The antifungal effect of silver nanoparticles on Trichosporon asahii.

Silver nanoparticles are receiving increasing attention in biomedical applications. This study aims at evaluating the antifungal properties of silver nanoparticles against the pathogenic fungus Trichosporon asahii. The growth of T. asahii on potato dextrose agar medium containing different concentrations of silver nanoparticles was examined and the antifungal effect was evaluated using minimum inhibitory concentration. Scanning and transmission electron microscopy were also used to investigate the antifungal effect of silver nanoparticles on T. asahii. Silver nanoparticles had a significant inhibitory effect on the growth of T. asahii. The minimum inhibitory concentration of silver nanoparticles against T. asahii was 0.5 μg/mL, which was lower than amphotericin B, 5-flucytosine, caspofungin, terbinafine, fluconazole, and itraconazole and higher than voriconazole. Silver nanoparticles obviously damaged the cell wall, cell membrane, mitochondria, chromatin, and ribosome. Our results demonstrate that silver nanoparticles have good antifungal activity against T. asahii. Based on our electron microscopy observations, silver nanoparticles may inhibit the growth of T. asahii by permeating the fungal cell and damaging the cell wall and cellular components.

Assessment of silver nanoparticle-induced physiological and molecular changes in Arabidopsis thaliana.

In this study, the effect of silver nanoparticles and silver ions on Arabidopsis thaliana was investigated at physiological and molecular levels. The seedlings were grown in sublethal concentrations of silver nanoparticles and silver ions (0.2, 0.5, and 1 mg/L) in 1/4 Hoagland's medium for 14 days under submerged hydroponic conditions. Significantly higher reduction in the total chlorophyll and increase in anthocyanin content were observed after exposure to 0.5 and 1 mg/L silver nanoparticles as compared to similar concentrations of silver ions. Lipid peroxidation increased significantly after exposure to 0.2, 0.5, and 1 mg/L of silver nanoparticles and 0.5 and 1 mg/L of silver ions. Qualitative analysis with dichloro-dihydro-fluorescein diacetate and rhodamine 123 fluorescence showed a dose-dependent increase in reactive oxygen species production and changes in mitochondrial membrane potential in the roots of seedlings exposed to different concentrations of silver nanoparticles. Real-time PCR analysis showed significant upregulation in the expression of sulfur assimilation, glutathione biosynthesis, glutathione S-transferase, and glutathione reductase genes upon exposure to silver nanoparticles as compared with silver ions. Overall, based on the physiological and molecular level responses, it was observed that exposure to silver nanoparticles exerted more toxic response than silver ions in A. thaliana.

The Effect of different Concentrations of Silver Nanoparticles on Enzyme Activity and Liver Tissue of Adult Male Wistar Rats in-vivo Condition

Nanotechnology as a branch of science which is related to nano materials helps in overcoming the limitations of size and can change the outlook of the world regarding science. Silver nano particles, due to their strong antimicrobial properties, are widely applicable in different industries. So, research on nano silver properties and its harmful effects on human and environment is critical. The aim of the present study is testing the harmful properties of Silver nano particles, in the size 18 to 32 nm, on enzymes and tissues of liver in Wistar rats. At first 50 adult male Wistar rats were picked and concentrations 5, 10, 20 and 40 ppm of Silver nano particle were tested on AST, ALT, ALP and GGT enzymes. Results showed that only 40 ppm of silver nano particle possesses a meaningful effect on ALT enzyme, and none of the other concentrations has meaningful effect on AST, ALP and GGT. Moreover, histopathology test from liver tissue revealed no damage in liver cells. As nano silver shows harmful effects on a broad range of cells, predetermined dosages of nano silver in limited amounts are suggested.

Kinetic evaluation study on the bioactivity of silver doped hydroxyapatite-polyvinyl alcohol nanocomposites

This work investigates the effect of adding silver nanoparticles (NPs) in ppm on the bioactivity of hydroxyapatite/polyvinyl alcohol nanocomposites (HAV). HAV prepared by an in situ biomimetic approach was doped with different concentrations of silver NPs (HAV-Ag), and the formed powder samples were characterized by different techniques such as Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-EOS), X-ray diffraction, transmission electron microscope, and Fourier Transform Infrared Spectroscopy. Bioactivity was evaluated in simulated body fluid through studying the kinetics of Ca and P uptake onto the different HAV-Ag nanocomposites. Uptake profiles of Ca and P were well described by a pseudo-second order kinetic model, and the obtained kinetic parameters confirmed that the highest uptake capacities were achieved by adding less than 0.001 ppm of silver NPs which is an amount not detectable by ICP. Furthermore, HAV-Ag nanocomposites were shown to be non-toxic as well as have a strong antibacterial effect. Silver NPs significantly enhanced the bioactivity of HAV nanocomposites and thus the developed nanocomposites promise to be excellent biomaterials for bone and reconstructive surgery applications.