Concentration Of Silver Nanoparticles Research Articles

Evaluation of the Cytotoxic Effects of Concomitant Use of Ag/ZnO Nanoparticles and Curcumin on MCF7 Breast Cancer Cell Line

Introduction: Cancer is the second cause of death. The use of a new drug delivery system that can deliver the drug to the tumor site and prevent it from entering the body's natural tissues is essential. Metal oxide nanoparticles have been considered one of the effective candidates for cancer treatment. For this reason, our study was conducted to investigate the cytotoxic effect of the simultaneous use of Ag/ZnO nanoparticles and curcumin on the Michigan Cancer Foundation-7 (MCF7) breast cancer cell line. Method: The MTT colorimetric method was used to investigate the synergistic effects of zinc oxide silver nanoparticles and curcumin. Cells with different concentrations of zinc oxide silver nanoparticles and curcumin, including 3.9, 7.8, 15.62, 31.25, 62.5, 125, 250, 500, and 1000 micrograms/ml during 24 and 48 h were incubated in triplicate to observe the synergistic effects of each of these concentrations, ratios of 1 to 1, 0.5 to 0.5, 0.25 to 0.75 of zinc oxide silver nanoparticles and curcumin were used. The viability of the cells treated with the drug was determined in the form of the percentage of light absorption of the produced formazan and was shown in a two-dimensional curve. Results: The effect of Ag/ZnO nanoparticles alone on the survival rate of cancer cells had a significant difference with curcumin. In addition, in the simultaneous examination of Ag/ZnO nanoparticles and curcumin, much more cytotoxicity was observed than in Ag/ZnO alone. Conclusion: In general, the simultaneous use of chemotherapy drugs and nanoparticles can decrease the concentration of chemotherapy drugs used in cancer treatment.

Оценка экотоксичности химических соединений серебра по показателям фитотоксичности чернозема обыкновенного

The study assessed the ecotoxicity of various chemical compounds of silver (nitrate, oxide, sulfide, nanoparticles) by indicators of phytotoxicity of ordinary chernozem. The effect of nitrate, oxide, sulfide and silver nanoparticles in concentrations of 0.5; 1; 5; 10; 50 and 100 mg/kg of ordinary chernozem on the germination and length of radish roots 30 days after contamination was evaluated. In most cases, a negative effect of silver chemical compounds on phytotoxic indicators of ordinary chernozem was noted. The degree of ecotoxicity of silver is affected by its concentration in the soil. Silver nitrate, which is highly soluble in water and provides greater mobility of silver in the soil in the form of Ag2+, has a somewhat greater ecotoxicity. Practically insoluble in water forms showed slightly less negative impact. According to the germination of radish, a number of toxicity of chemical compounds (% of control) has been compiled: nitrate (84) > sulfide (87) > oxide (88) > nanoparticles (91); according to the length of the radish roots, a number of toxicity of chemical compounds of silver (% of the control) has been compiled: nitrate (90) > oxide (95) ≥ nanoparticles (95) ≥ sulfide (95). Keywords: SOIL, NITRATE, OXIDE, SULFIDE, NANOPARTICLES, GERMINATION, ROOT LENGTH, CONTAMINATION

Preparation of Highly Concentrated Uniform-Sized Silver Nanoparticles via Use of Thermoresponsive Zwitterionic Surfactants.

Despite the popular use of citrate for the reduction of silver ions, this process suffers from slow crystal growth and broad size distribution. The rapid and effective synthesis of highly concentrated and stable spherical silver nanoparticles (AgNPs) confined in the surfactant-rich phase of thermoresponsive 3-(alkyldimethylammonio)-propyl sulfate surfactants obtained after reaction with citrate ions at high temperature is described. The present approach using the zwitterionic surfactant offers an alternative rapid approach for production of AgNPs and an in situ phase separation step that serves to "extract" and concentrate the AgNPs in the surfactant-rich phase. Almost all (synthetic yield 99.9%, extraction efficiency 98.6%) of the synthesized AgNPs with a diameter of 21.0 ± 2.5 nm were incorporated into the phase-separated surfactant-rich phase at pH 11, and the capacity (maximum concentration) was 3.4 × 1013 particles/mL. The AgNPs were stable upon long-term storage (at least 3 months).

Photocatalytic activation of Ag-doped SrSnO3 nanorods under visible light for reduction of p-nitrophenol and methylene blue mineralization

The utilization of solar energy for the treatment of wastewater pollutants by photocatalysts has been considered a promising solution to address environmental problems. Herein, we have synthesized silver nanoparticle-doped strontium stannate (Ag-doped SrSnO3) nanorods by hydrothermal method followed by ultrasonic treatment. The developed nanocomposites were applied for photocatalytic reduction of p-nitrophenol (4-NP) and methylene blue (MB) mineralization under visible light illumination. The effect of hydrothermal duration time (16–25) h, Cetyltrimethylammonium bromide (CTAB) and silver nanoparticles (Ag NPs) concentration (0.5–2.5) wt% on the crystal, surface, optical, photoluminescence as well as photocatalytic activity were studied. A well-defined crystalline cubic phase of SrSnO3 was obtained. CTAB inhibits the crystal growth of SrSnO3. Reduction of 4-NP and MB mineralization were used as two-model reactions for testing the effect of Ag doping concentration on the photocatalytic activities of Ag/SrSnO3 under visible light illumination. The obtained results show that 2.0 wt% of Ag-doped SrSnO3 exhibits efficient photocatalytic reduction of 4-NP with 98.2% conversion within 5 min of reaction time. Also, 87% of the MB sample was mineralized after 1 h of visible illumination using 2.0% Ag/SrSnO3 in the presence of H2O2. Besides, we have discussed the possible photocatalytic mechanism for reduction of 4-NP and mineralization of MB using 2.0 wt% of Ag doped SrSnO3 under visible light illumination.

Synthesis and synergistic effect of antibacterial composites based on concentrated hydrosols of silver nanoparticles combined with cephalosporins antibiotics

Silver nanoparticles may be used as potential antimicrobial agents. Concentrated silver nanoparticles (AgNPs) were synthesised by the Carey Lee method. Then, antibiotics, such as disodium ceftriaxone, sodium cefotaxime, sodium cefazolin and sodium cefoperazone, were added to the AgNPs at the ratio of AgNPs:antibiotic = 5:1. The concentrated hydrosols were examined using UV–Vis, FTIR-spectroscopy, dynamic light scattering and transmission electron microscopy. The spectra plasmon resonance of silver nanoparticles and their combination with antibiotics had a single strong peak at 412–415 nm. The transmission electron microscopy micrographs showed different forms. The average size of AgNPs-antibiotic particles was smaller than that of AgNPs. The antibacterial activities of AgNPs, antibiotics and AgNPs-antibiotics were determined by the disk diffusion method against Staphylococcus aureus and Escherichia coli. The most significant enhancement of the antibacterial effect over the antibiotic was demonstrated by AgNPs-disodium ceftriaxone against E.coli. Also, the minimal inhibitory concentration (MIC) of the AgNPs-antibiotics was defined. All the AgNPs-antibiotic exhibited a synergistic enhancement by AgNPs and the antibiotic of antibacterial activity. A possible explanation of this phenomenon was proposed. Our results suggest that the synthesis of the concentrated hydrosol of the AgNPs-antibiotics is essential for studying similar nanosystems.

INVESTIGATING LOW DOSE OF WEED MEDIATED SILVER NANOPARTICLES AGAINST PATHOGENIC BACTERIA

Weeds are undesirable and unpleasant plants with robust growth. Around 18,000 weed species outcast native biodiversity and responsible for tremendous economic losses. Plants were used to treat numerous ailments since ancient times. Antimicrobial resistance (AMR) is an emerging global health problem, where approximately 700,000 people lose their life each year from AMR infections. Minimum inhibitory concentration of Biogenic silver nanoparticles against pathogenic bacterial strain has not been reported previously. This study aims to elucidate lowest biogenic Alkanna tinctoria mediated silver nanoparticles dose to treat bacterial infections. Qualitative phytochemical analysis performed using standard tests. The synthesized silver nanoparticles were characterized visually, UV–Vis spectroscopy and using X-ray diffraction. Minimum inhibitory concentration of biogenic silver nanoparticles was tested against gram positive (S. aureus) and gram-negative bacteria (E. coli). Alkanna tinctoria leave were positive for alkaloids, carbohydrate, saponins, amino acids, and fixed oil. The synthesized silver nanoparticles were in range of 60 to 73nm. Silver nanoparticles significantly affected E. coli as compared to S. aureus. The MIC for E. coli was recorded as 46.87 μg/mL and 93.75 μg/mL was effective against S.aureus. Search of naive plants as novel therapeutic agents along with nanotechnology can bring revolution in the field of drug development and medical sciences.

Exploring in vitro effect of silver nanoparticles and Holothuria parva extracts on kinetics and stability of α-amylase.

Diabetes is a chronic metabolic disorder characterized by elevated blood glucose levels. Major limitations of synthetic drugs, including high cost, efficacy, and adverse side effects, have prompted researchers to seek more effective and low-cost alternative therapies with fewer adverse effects. Marine life forms are considered the most important sources of biologically active natural products due to their secondary metabolites. In this research, sea cucumber Holothuria parva was collected from coastal areas of Bandar Lengeh, Hormozgan, Iran, and was then subjected to extraction. The results showed that compounds extracted from Holothuria parva had a stimulatory effect on enzyme activity, and in the presence of these compounds, the Vmax value of the enzyme was increased about two times, while the Km value was reduced. The phosphate buffer form of extracts had the greatest impact on enzyme activity. Upon an increase in the concentration of silver nanoparticles (AgNPs), the α-amylase activity was inhibited in parallel. Silver nanoparticles exhibited the highest enzyme inhibition with an IC50 of 0.86mg/ml. Silver nanoparticles showed anti-α-amylase activity and had the ability to decrease intestinal glucose uptake in diabetic individuals when prescribed as a novel supplementary medicine.

Dialdehyde modification of laminarin for facile synthesis of ultrafine silver nanoparticles with excellent antibacterial and wound healing properties

Laminarin is a promising marine biopolymer that is abundant, non-toxic, and biodegradable. However, laminarin has a weak reduction potential for metal ions, resulting in the synthesis of a lower content of large-sized silver nanoparticles (AgNPs). Here, we showed that after the introduction of aldehyde groups, the reduction potential of laminarin increased, decreasing the synthesis time and increasing the density of AgNPs. 1H NMR and FT-IR confirmed the addition of aldehyde groups on laminarin. The dialdehyde-modified laminarin (DLAM) showed in situ, simple, and rapid synthesis of ultrasmall-sized spherical AgNPs (<10 nm), as revealed by TEM images. The aldehyde and carboxyl groups of DLAM act as synchronized reducing and anchoring agents. The conversion of Ag ions into AgNPs-DLAM was confirmed by UV–Vis spectrophotometer, FTIR, XRD, and XPS analysis. The AgNPs-DLAM showed significantly enhanced antibacterial activities than silver ions against Escherichia coli and Staphylococcus aureus via causing morphological changes and pore formations in bacterial cells. The AgNPs-DLAM also inhibited bacterial biofilm formation. In contrast, the AgNPs-DLAM showed negligible toxicity toward human keratinocytes. Furthermore, AgNPs-DLAM increased the migration of human keratinocytes, indicating efficient wound healing properties. Thus, signifying the importance of AgNPs-DLAM in clinical applications.

Antibacterial and antibiofilm effects of silver nanoparticles against the uropathogen Escherichia coli U12

The drug-resistant bacterial strains' emergence increases day by day. This may be a result of biofilm presence, which protects bacteria from antimicrobial agents. Thus, new approaches must be used to control biofilm-related infections in healthcare settings. In such a study, biological silver nanoparticles were introduced in such a study as an anti-biofilm agent against multidrug-resistant E. coli U12 on urinary catheters. Seven different silver nanoparticles concentrations were tested for their antimicrobial activities. Also, anti-biofilm activities against E. coli U12 were tested. Using the dilution method, the silver nanoparticles concentration of 85 μg/ml was the MIC (Minimum Inhibitory Concentration) that had excellent biocompatibility and showed significant antibacterial activity against E. coli U12. Scanning electron microscopy (SEM) confirmed that the highest efficient dose of silver nanoparticles was 340 μg/ml at 144 h that reduced adhesion of E. coli U12 to the urinary catheter. E. coli U12 cells ruptured cell walls and cell membranes after being examined using transmission electron microscopy (TEM). Thus, biologically prepared silver nanoparticles could be used to coat medical devices since it is effective and promising to inhibit biofilm formation by impregnating urinary catheters with silver nanoparticles.

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.

Seed-mediated growth of highly concentrated silver nanoparticles on a flexible substrate for applications in SERS-based trace detection

In this work, we demonstrate a seeded approach for in-situ growth of Ag nanostructures directly on filter paper. Multiple growth steps were used to increase the size of Ag NPs grown from Au seeds. Essentially, this procedure generated a high density of NPs on filter paper which in turn provided high enhancement of Raman signals. We have seen a marked increase in the SERS enhancement factor with each growth step. Moreover, the relative standard deviation (RSD) values decreased with each growth step, indicating the relatively uniform distribution of NPs on the substrate. With four growth steps, we were able to achieve an EF of 9.28 × 104 with RSD values of 14%. In particular, the detection limit of 10 nM for CV has been achieved by both solution drying and swabbing. Moreover, swab detection of explosive material ammonium nitrate down to 100 µM has also been demonstrated.

Dynamics and enzymatic degradation of exopolymer particles under increasing concentrations of silver ions and nanoparticles during a marine mesocosm experiment

Pollution of the marine environment is an emerging threat. Nowadays, engineered nanoparticles (&amp;lt;100 nm) such as zinc, copper and silver are widely used as antimicrobial agents, therefore often present in daily-life products. Consequently, the demand and production of nanoparticles are expected to increase. Here, we specifically focus on silver nanoparticles (AgNP). Once released into the environment, AgNPs pose an obvious ecotoxicological risk, potentially affecting ecosystem structure and functioning. For instance, phytoplankton-derived exudates, rich in acidic polysaccharides and amino acids, can abiotically aggregate into microgels such as transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP). Hence, microgels can bridge dissolved and particulate size fractions and facilitate aggregate formation with organic and mineral particles. Both physical and chemical properties make TEP and CSP attractive nutrient hotspots for heterotrophic bacterioplankton. Bacteria, in turn, utilize extracellular enzymes to access these carbon and nitrogen pools. However, knowledge about the mechanisms by which AgNPs might interact with and affect the biogeochemical cycling of TEP and CSP is still insufficient. Therefore, we conducted a mesocosm experiment in the Eastern Mediterranean Sea and investigated the effects of environmentally relevant concentrations of silver ions (Ag+) and AgNP on the properties of TEP and CSP (i.e., area and abundance) along with enzymatic activity measurements. Our results showed that cyanobacteria were likely the primary source of CSP in the ultra-oligotrophic Mediterranean Sea. Also, CSP contributed more to the microgel pool than TEP, as indicated by a strong relationship between CSP and heterotrophic microbial dynamics. While silver (i.e., Ag+ or AgNP) had overall only marginal effects, both species affected the relationships between cell-specific LAPase activity and CSP and cell-specific APase activity and phosphate levels. Thus, Ag+ and AgNP have the potential to regulate microgel dynamics. However, future studies are needed to derive a robust understanding of the effects of silver pollution on the coupling of microgel formation and degradation and the follow-on effect on biogeochemical cycles.

The effect of Lactobacillus casei and Bacillus coagulans probiotics on liver damage induced by silver nanoparticles and expression of Bax, Bcl2 and Caspase 3 genes in male rats.

In this study, we aimed to evaluate the effect of Bacillus coagulans and Lactobacillus casei probiotics on liver damage induced by silver nanoparticles and expression of Bax, Bcl2 and Caspase 3 genes in rats. 32 adult male Wistar rats were divided into four healthy groups (control), the group receiving silver nanoparticles treated with L. casei, the group receiving silver nanoparticles treated with B. coagulans and the group receiving only silver nanoparticles. The effect of nanoparticles was induced by intraperitoneal injection of silver nanoparticles prepared from nettle at a dose of 50 mg/kg and entered the liver tissue through the bloodstream. Two days after injection, probiotic treatment with 109 CFU was performed by gavage for 30 days. One day after the last gavage, rat liver tissue weight was assessed. Also, the total amount of RNA was extracted from treated, and healthy tissues, as well as induced silver nanoparticles tissues, then evaluated by Real Time PCR. Data were evaluated using one-way Anova, Tukey test. Based on the biochemical results of this study, exposure of rats to different concentrations of silver nanoparticles compared with the control group caused a significant increase in the serum levels of alanine transaminase (ALT) and aspartate transaminase (AST), alkaline phosphatase (ALP), especially at high concentrations. Evaluation of damage and histopathological lesions showed that silver nanoparticles in different concentrations caused different damage to liver tissue, so that, necrosis, inflammatory cell infiltration and vascular degeneration were observed at different concentrations by silver nanoparticles. In the present study, the effects of L. casei cell extract on increasing the expression of Bax proapoptotic gene and decreasing Bcl2 gene expression in cancer cells and inducing programmed cell death were shown. In this study, the expression of Bax, Bcl-2 and Caspase-3 genes in the group receiving silver nanoparticles and in the groups treated with probiotics showed significant changes compared to the control group. It can be concluded that the function of silver nanoparticles and the effects of relative improvement of probiotics are from the internal route of apoptosis and factors such as dose, nanoparticle size and nanoparticle coating have an important role in the toxicity of silver nanoparticles, thus the destructive effects on liver tissue could be increased by increasing the concentration of silver nanoparticles.

Peristaltic pumping of hybrid nanofluid between concentric tubes with magnetic device effects: Applications to human endoscopy

The applications of hybrid nanomaterials report excellent thermal performances and convey applications in various processes like energy production, extrusion processes, nuclear reaction, manufacturing and engineering processes, industrial domains, aero-spaces etc. Additionally, the impacts of magnetic devices in advance endoscopy and biological transport phenomena are also a hot topic of research in the current era. This study deals with the physical influences of magnetic device on the peristaltic transport of a viscoplastic nanofluid between the two-dimensional curved concentric tubes. The curved shape structure of flow geometry from the external side with a flexible complex nature of the peristaltic endoscope present inside that is similar to the endoscopy of a living organ. The non-Newtonian Casson liquid polymer is employed for assist the dynamic of viscoplastic materials. The concentration of silver (Ag) and alumina (Al2O3) nanoparticles are utilized in the clay as a base fluid. The governing equations are modeled by using the curvilinear coordinates. The conducting investigation is worked out for creeping pattern and under the high wavelength consideration. The analytical proceedings for flow features, for examples, axial velocity profile, pressure gradient, pressure rise, shearing stress tensor and temperature profile, are obtained by using integration technique. It is noted that the velocity magnitude for viscous fluid is larger in magnitude as compared with the viscoplastic fluid. The magnitude of temperature rate get slower variation for volumetric concentration parameter (range of concentration parameter is 0%–4%). The current model has been used in bio-engineering processes, industrial fluid mechanics, thermal processing, endoscopy of living organs and cooling systems.

Effect of Titania and Silver Nanoparticles on the Tensile Strength of Cement-Like Mineral Trioxide Aggregate

Several attempts have been conducted to improve the mechanical properties of mineral trioxide aggregate (MTA), including the addition of various nanoparticle materials such as silver and titania. The smaller the added material, the higher the material’s ability to fill the cavity of MTA, thus increasing the tensile strength of MTA after hydration. In this study, the effect of silver nanoparticles (AgNP) concentration and titania (TiO2) mass variation on the tensile strength of MTA was investigated. The ratio of MTA mass to AgNP volume used was 1 g to 330 μL, while TiO2 was added to MTA powder in a solid-solid state with a mass variation. The results show that the addition of AgNP and TiO2 to MTA powder can significantly increase the tensile strength of MTA from 0.404±0.125 to 1.044±0.021 and 1.378±0.391 MPa for 1.5% Ag and 0.5% TiO2, respectively.

Physicochemical Parameters and Antibacterial Activity of Biosynthesized Silver Nanoparticles from Carica papaya Leaf Extract

In this research work, Silver nanoparticles were synthesized from Carica papaya leaf extract via green route. The physicochemical parameters including boiling point, color, odor, density, pH as well as the solubility of papaya leaf extract were first determined before proceeding with the synthesis of silver nanoparticles. The formation of Silver Nanoparticles first, was identified by color change from light brown to dark brown after the nucleation of the metal ions indicating that phytoconstituents of Carica papaya resulted in the reduction of Ag+ to Ag0, a phenomenon that could be attributed to the surface Plasmon absorption. The bio fabricated silver nanoparticles were characterized using UV – Visible and SEM to be certain of its formation before being deployed in the antibacterial studies. The UV-Vis spectral analysis showed maximum absorbance of 1.05 at a corresponding wavelength (λ max) of 400nm reflecting the surface Plasmon resonance of silver NPs from papaya leaves which is characteristic of Silver Nanoparticles. SEM image revealed that, the synthesized silver nanoparticles have a spinel like structure and an average size of about 50nm. The antibacterial studies of Silver nanoparticles were conducted against B. subtilis, K. pneunoniae, P. aeruginosa, E. coli, and S. typhi. Different concentrations of 100, 200, 300, 400 and 500μg/L of Silver nanoparticles were tested against each pathogen. The inhibition zone increases generally with increase in concentrations of silver nanoparticles. At higher concentration of 500μg/L, the zones of inhibition were in the following order; 24.44mm, 17.64mm, 17.52mm, 16.88mm, and 16.00mm for B. subtilis, P. aeruginosa, E. coli, K. pneumoniae and S. typhi respectively. The zone of inhibition for Augmentin was found to be higher compared to silver nanoparticles for each pathogen, except for P. aeruginosa where it is almost the same, an indication of high activity of silver nanoparticles against P. aeruginosa due to the comparability with Augmentin. For each concentration investigated, B. subtilis demonstrated higher zone of inhibition as compared to other pathogens studied in this work, hence, Ag NPs may be a potential antibiotic.

Investigation the effects of silver nanoparticles and gold nanoparticles on expression of bap and csu genes in biofilm formation of Acinetobacter baumannii.

Acinetobacter baumannii is one of the main pathogens of the hospital and causes various infections. csu A/BABCDE involved in the initial surface attachment during biofilm formation and bap gene produces specific proteins at the cell surface that play a direct role in formation of biofilm and the infectivity of this bacterium. The aim of this study was to investigate the effect of silver nanoparticles and gold nanoparticles on the expression of bap and csu genes in the Acinetobacter baumannii biofilm formation. The susceptibility test was performed to determine the MIC of silver nanoparticles, gold nanoparticles and gold-vancomycin nanoparticles performed by broth dilution method on A. baumannii strains. The ability of biofilms formation in strains treated by MIC of silver nanoparticles and gold-vancomycin nanoparticles were evaluated by microtiter plate method and A. baumannii ATCC19606 used as control. Expression of the csu and bap genes were determinded by measuring the cognate mRNA level by real-time PCR. In present study, gold nanoparticles could not prevent the growth and biofilm formation of A. baumannii strains. The MIC concentration of silver nanoparticles and vancomycin- gold nanoparticles were 6.25 μg/ml and 0.625 μg/ml respectively and MBC concenteration of nanoparticles for 70% of strain was 12.5 μg/ml and 1.25 μg/ml respectively. Real-time PCR and data analysis, determined that the expression of bap, csuC and csuE genes in A. baumannii strains treated with MIC concentration (6.25 μg/ml) of silver nanoparticles decreased compared to control groups. Also, the expression of csuC and csuE genes in strains treated with MIC concentration (0.625 μg/ml) of vancomycin -gold nanoparticles increased, however the expression of bap was decreased compared to the control groups. Due to the inhibitory effect of silver nanoparticles and gold-vancomycin nanoparticles against A. baumannii biofilm formation and genes expression, they can probably be used for prevent of biofilm formation in medical instrument or can be use for treatment of infections with or without antibiotic.

The effect of silver nanoparticles toward properties and antibacterial activity of silver-alginate nanocomposite films

Preparation of silver-alginate nanocomposite films as an antibacterial material has been carried out through the casting method of colloidal nanocomposite silver-alginate. Colloidal was made by chemical reduction of AgNO3 precursor salts using microwave irradiation with alginate as a stabilizer and reducing agent and NaOH as an accelerator. The appearance of a brownish yellow color, due to the addition of variation of AgNO3, and the localized surface plasmon resonance (LSPR) phenomenon were identified by UV-Vis spectrophotometer, indicating that silver nanoparticles have been formed. The properties of obtained silver nanoparticles was then examined. The shape and size distribution of silver particles were determined based on the image on transmission electron microscopy (TEM), chemical properties (FTIR), mechanical, crystallinity (XRD), and surface morphology (SEM). Testing of antibacterial activity was performed on silver-alginate nanocomposite films using the diffusion method for gram-positive (S. aureus and MRSA) and gram-negative (E. coli and ESBL) bacteria. The results showed that based on the UV-Vis spectrophotometer characterization results, the LSPR phenomenon appeared at the absorption peak of 401.01–409.00 nm, denoting silver nanoparticles with a spherical shape of 3–22 nm have been formed. Further, the presence of silver nanoparticles affected the mechanical properties of the film, where the tensile strength of the film tended to decrease with the increase in the silver nanoparticles concentration while the crystallinity increased. Next, based on the SEM results the nanocomposite films of silver-alginate had a rough and porous structure. The nanocomposite film had antibacterial activity against E. coli, S. aureus, ESBL, and MRSA. The antibacterial activity film was affected by the concentration of silver nanoparticles.

In-vitro Study on the Anti-leishmania Effects of Silver Nanoparticles on Leishmanaia Major Promastigotes

Background and Objectives: Cutaneous leishmaniasis is one of the most important health-threatening diseases in Iran and other countries. Glucantime is currently used to treat this disease, but due to its side effects and high resistance, alternative therapies such as the use of nanoparticles have been considered by researchers. This study aims to investigate the anti-leishmania activity of silver nanoparticles on Leishmania major in vitro. Methods: This is an experimental study on the anti-leishmania activities of silver nanoparticles at different concentrations of 0.75-0.96 µg/ml after 24, 48 and 72 hours of exposure to 106 live Leishmania major promastigotes. The numbers of live parasites were counted by Trypan Blue on a neobar slide using optical microscope (Hemocytometer method). Glucantime and distilled water were considered as positive and negative controls, respectively. The half-maximal inhibitory concentration (IC50) was calculated by SigmaPlot™ software, v‌ersion 13. All reactions were done three times and their average was considered as final result. Results: All concentrations of silver nanoparticles had anti-leishmania activity, where the concentration of 96 µg/ml had the highest effect (100%) 72 hours after exposure. The IC50 was obtained 36.67, 27.2 and 21.08 µg/ml after 24, 48 and 72 hours of exposure, respectively. Conclusion: Silver nanoparticles have an inhibitory effect on the growth of Leishmania major in different concentrations. However, further in-vivo studies are needed to determine the effictivness of silver nanoparticles.

Antibiofilm Efficacy of Silver Nanoparticles Alone or Mixed with Calcium Hydroxide as Intracanal Medicaments: An Ex-Vivo Analysis

IntroductionThis study aimed to determine the most effective antibiofilm concentration of silver nanoparticles (AgNPs) alone or in combination with calcium hydroxide (Ca[OH]2) against Fusobacterium nucleatum biofilm. MethodsThe minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs alone or with Ca(OH)2 were determined. Dentin slices were sterilized and inoculated with F. nucleatum for 3 weeks to establish a biofilm. Samples were randomly assigned to determine the MIC and MBC for AgNPs alone or mixed with Ca(OH)2. A higher concentration of AgNPs for both preparations was also used. Triple antibiotic paste, Ca(OH)2, and saline were used as controls. Specimens in each group were subdivided over 2 observation periods: 7 and 14 days. At the end of each period, specimens were analyzed with 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to determine the metabolic activity. Also, samples from each group were assessed by scanning electron microscopy. ResultsThe MIC and MBC of AgNPs alone against F. nucleatum coincided at 0.04%. The combination of AgNPs + Ca(OH)2 exhibited a lower MIC and MBC of 0.03%. MTT analysis showed a significant reduction in bacterial viability in all groups compared with negative controls (P < .05). A more substantial reduction in bacterial cells was observed with increasing concentrations of AgNPs at both periods. The combination (AgNPs [0.06%] + Ca[OH]2) was the most potent against F. nucleatum. ConclusionsThe findings demonstrated that combining AgNPs with Ca(OH)2 was more effective on the F. nucleatum biofilm than either material alone, suggesting a combined effect.