Characteristics Of Silver Nanoparticles Research Articles

Antibacterial Activity Test of Ag Nanoparticle Soap Turi Leaf Extract (Sesbania grandiflora) Against Staphylococcus aureus Bacteria

Silver metal nanoparticles have biocidal properties as a non-toxic inorganic antibacterial agent. Flavonoid compounds from the Turi Leaf (Sesbania grandiflora) plant extract as a natural bio reductant. In the research, UV-Vis spectrophotometric testing parameters and antibacterial soap preparations were carried out. Synthesis and Characteristics of Silver Nanoparticles were carried out, with soap preparations made into 3 formulas with different variations in Agno3 concentration, namely 1 mM, 2 mM, and 3 mM and antibacterial activity tested using well diffusion. The results of the absorption spectrum of Ag nanoparticles show the highest peak at a value of 280-290 nm. In the antibacterial activity test, the greater the AgNO3 concentration in the Ag nanoparticle soap, the greater the inhibition zone created by Staphylococcus aureus bacteria. The optimum concentration in soap preparations is 3 mM producing a wavelength of 300 nm with an absorbance value of 1.105. In terms of antibacterial activity, the most effective way to inhibit the growth of Staphylococcus aureus bacteria is formulation III, with an inhibitory power of 7.69 cm2 .

Synthesis of nanosilver with simpur leaf (Dillenia indica) modified PVA as antibacterial

Synthesis of silver nanoparticles using a bioreductant of simpur leaf extract to minimize the use of inorganic materials that are harmful and not environmentally friendly. Silver nanoparticles with the bioreduction method, the bioreductant solution was mixed with AgNO3 precursor and the addition of PVA concentrations was 0%, 0.75%, 1.5% and 3%. The purpose of this study was to determine the effect of PVA on the characteristics of silver nanoparticles on antibacterial activity. Analysis of functional groups in simpur leaf extract and Ag/PVA 0.75% using FTIR Spectrophotometer showed wave numbers 3443 cm-1 and 3441 cm-1 the presence of -OH groups and at wave numbers 1640 cm-1 and 1638 cm-1 the presence of C=O groups. UV-Vis analysis showed the optimum wavelength in the 3% PVA variation absorption region showed an absorbance value of 429 nm with an average size of 8.19 nm silver nanoparticles. Inhibition of silver nanoparticles against bacterial growth Escherichia coli and Staphylococcus aureus the highest concentration was at 100% with an inhibition zone diameter of 10.33 mm and 11.58 mm in the strong category.

Characterization of Silver Nanoparticle Electrolysis Method with UV-Vis Spectrometer, Atomic Absorption Spectrophotometer, and Particle Size Analyzer

This work reports the production and characteristics of silver nanoparticles by electrolysis method at different voltages and electrolysis time with respect to their soluble concentration. This research is an experimental research. The research sample was the result of a solution of silver nanoparticles by the electrolysis method. The purpose of this research was to determine the effect of electrolysis voltage on the concentration of silver nanoparticles, the effect of electrolysis time on the concentration of silver nanoparticles, and characterization using UV-Vis, AAS and PSA. In this research there are two stages, namely the production stage and the characterization stage. The production of silver nanoparticles was carried out using 99% AgBr rods and aquades by electrolysis method. Characterization was carried out by testing on UV-Vis, AAS and PSA spectrometers to determine light absorption, ionic silver concentration and silver nanoparticle size. The results of this research indicate that the greater the electrolysis voltage and time, the higher the concentration of the solution obtained. The concentrations obtained at each voltage were 38 ppm, 42 ppm and 54 ppm. Characterization using UV-VIS spectrometer showed that the silver nanoparticle solution at each concentration was able to absorb light at wavelengths of 419.50 nm, 442 nm and 431 nm with absorbance peaks of 1,158, 2,989, and 0.904. Characterization using AAS showed that the content of silver nanoparticles in solution at each concentration were 8.7 ppm, 15 ppm and 17 ppm. Characterization using PSA showed that the solution at each concentration had silver nanoparticle sizes were 110.7 nm, 209.2 nm, 175.2 nm.

Synthesis, Morphology, Structure, and Spectral Characteristics of Silver Nanoparticles Stabilized by Amphiphilic Molecular Brushes of Varying Topology

Synthesis, Morphology, Structure, and Spectral Characteristics of Silver Nanoparticles Stabilized by Amphiphilic Molecular Brushes of Varying Topology

Physicochemical characteristics of silver nanoparticles: influence of carbonate alkalinity

Physicochemical characteristics of silver nanoparticles: influence of carbonate alkalinity

Synthesis and characterization of antibacterial silver nanoparticles using essential oils of crown imperial leaves, bulbs and petals

In this research, the essential oils obtained from leaves, bulbs and petals of crown imperial plant are used as reducing agents to fabricate silver nanoparticles. The aromatic hydrocarbons, alkenes, ketenes and alkaloids are among the compounds identified in the essential oils as detected by gas chromatography mass spectrometry. The characteristics of silver nanoparticles are investigated by field emission scanning electron microscopy, transmission electron microscopy and XRD. The chemical groups and surface resonance characteristics of the samples are revealed by Fourier transform infrared spectroscopy and UV-Visible spectroscopy, accordingly. The field emission scanning electron microscopy results show that the silver nanoparticles form nanoscale spheres with a mean diameter of 27 ± 14 nm in case of the sample obtained by essential oil of petals as confirmed by transmission electron microscopy. This sample shows a UV-Visible absorption band at 450 nm. The antibacterial activity of the silver nanoparticles shows a remarkable inhibition capability against all of the tested bacteria, with the sample obtained from petals exhibiting the strongest antibacterial effect in agreement with the obtained minimum inhibitory concentration and minimum bactericidal concentration values. The cell viability assay using Vero cell line reveals a nearly constant viability rate above 125 μg/mL of silver nanoparticles.

Hydrodynamic Diameter of Silver Nanoparticles in Solutions of Nonionic Surfactants

Physicochemical characteristics of silver nanoparticles with known sizes are studied, depending on the concentration of nonionic surfactants and the concentration of the metal. Surfactants are used that form micelles of different sizes and different intensities of light scattering. It is shown that the surface tension and adhesion properties of solutions of nonionic surfactants are determined by the solvent in ranges of concentration lower than 1 mol/L. An approach based on spectrophotometry and viscosimetry is proposed that allows determination of the most likely reasons for discrepancies in the hydrodynamic diameter of nanoparticles in solutions of nonionic surfactants and the actual diameter of the nanoparticles.

In Situ Synthesis of Dental Resin Matrix Containing Silver Nanoparticles.

In this work, we investigated the influence of different concentrations of silver 2-ethylhexanoate on the synthesis and characteristics of silver nanoparticles (AgNPs) in resin matrix, as well as the antibacterial performance, mechanical properties and biocompatibility of the silver containing resin matrix, in order to provide a scientific basis for the application of AgNPs in restoration resins. The concentration of silver salt in resin matrix was set ranging from 0.05 wt% to 0.30 wt%. AgNPs were successfully synthesized in resin matrix by reducing silver ions in situ through photoinitiation. The results demonstrated that silver salt with low concentrations (≤0.20 wt%) had little influence on the degree of conversion, Knoop hardness and cell viability of silver resin matrix. However, silver salt with low concentrations (≤0.15 wt%) had little antibacterial activities against Streptococcus mutans. Therefore, it suggested that 0.20 wt% was a proper concentration for silver salt to be added into resin matrix, since silver salt at this concentration could exert a significantly antimicrobial activity without compromising the mechanical properties and biocompatibility of resin matrix.

Spectral characteristics of silver nanoparticles in polyacrylamide matrix in the presence of berberine molecules

The triple system with berberine, silver nanoparticles and polymeric matrix was studied optical spectroscopy methods. Silver nanoparticles were synthesized in situ in water solution of branched copolymers Dextran-graft-polyacrylamide. An adding the berberine to a solution of nanoparticles leads to the changes in the absorption spectra: the optical density in the range 370–470 nm decreases and the band shifts to the long-wave region of the spectrum. The quenching of the fluorescence of silver nanoparticles in presence of the berberine molecules has been detected. These spectral changes considered as an evidence of the aggregation processes caused by the berberine.

Antimicrobial activity of silver nanoparticles synthesized from Ficus benghalensis against human pathogens

In the context of present world Nanotechnology has found it's way in every important aspects of our daily lives from diagnostic techniques, drug delivery, sunscreens, antimicrobial bandages to disinfectants. In this study the synthesis of nanoparticles was done by reducing silver nitrate using the bacteria Bacillus species. Formation of nanoparticles was confirmed by UV-visible spectroscopy with maximum absorbance at 434nm, characteristic of silver nanoparticles by using various analytical studies. FTIR is taken to confirm the chemical bonding present in AgNPs. XRD and FE-SEM was used to determine the metallic characteristics of AgNPs as well as size and morphology of AgNPs. The size of AgNPs is 41.13nm. Disc diffusion method was done for antimicrobial activity, further comparative analysis and synergistic activity was determined. Comparative analysis of synthesized AgNPs was done with water, AgNO3, extracted samples and AgNPs. Further synergetic activity was done to confirm the antimicrobial activity of AgNPs. AgNPs shows good antimicrobial activity against human pathogens so it can be used in drug delivery system.

EXTRACELLULAR AND INTRACELLULAR SYNTHESIS OF SILVER NANOPARTICLES

<p>ABSTRACT<br />Objective: The cellular synthesis of nanoparticle is a green process and alternative for a conventional process for the preparation of silver nanoparticles.<br />In our research, focus has been given to the development of an efficient and eco-friendly viable process for the synthesis of silver nanoparticles using<br />cancer and non-cancerous cells, a cell culture that was isolated. The results of this investigation are observed that silver nanoparticles could be<br />induced to synthesis intra- and extra-cellularly using mammalian cells such as cancerous and non-cancerous cells.<br />Methods: The silver nanoparticles are synthesized by the cancer and non-cancerous cells such as HeLa (Homo sapiens, human), SiHa, and human<br />embryonic kidney-293 cell lines. The silver nanoparticles were characterized by ultraviolet (UV)-visible spectroscopy, transmission electron<br />microscopy (TEM), and X-ray powder diffraction (XRD).<br />Results: The silver nanoparticles exhibited maximum absorbance at 415 nm in UV-visible spectroscopy. The XRD confirms the characteristic of the<br />crystal lattice of silver nanoparticles by observing three peaks: Peak at 38 is due to reflection from (111), peak at 44 is due to reflection from (200),<br />and peak at 65 is due to reflection from (220). TEM images showed the formation of stable silver nanoparticles in the cell lines.<br />Conclusion: The method of extraction of intracellular/extracellular synthesis of silver nanoparticles was inexpensive, simple, and effective in large<br />scale with no need to use of complex process equipment. The cancer cell considered as a biological factory at nanoscale dimension which continued to<br />grow after synthesis of silver nanoparticles. The silver reduction by these cancer cells has occurred through energy-dependent processes that lead to<br />the high output of this reaction. Hence, this new approach of using a mammalian cell for the successful synthesis of nanosized silvers could be easily<br />scaled up, which establishes its commercial viability and also useful in the drug delivery and drug targeting.<br />Keywords: Silver nanoparticles, Cancer cells, Biosynthesis and characteristics of silver nanoparticles.</p><p> </p>

Interfacial adhesion enhancement of ink-jet printed transparent metallic grid electrodes induced by the coffee-ring effect

An effective strategy was developed to regulate the surface characteristics of silver nanoparticles and enormously enhance interfacial adhesion between transparent metal grids and substrates based on the coffee-ring effect.

Characteristics of silver nanoparticles in vehicles for biological applications

Silver nanoparticles (AgNPs) have been used for decades as anti-bacterial agents in various industrial fields such as cosmetics, health industry, food storage, textile coatings and environmental applications, although their toxicity is not fully recognized yet. Antimicrobial and catalytic activity of AgNPs depends on their size as well as structure, shape, size distribution, and physico-chemical environment. The unique properties of AgNPs require novel or modified toxicological methods for evaluation of their toxic potential combined with robust analytical methods for characterization of nanoparticles applied in relevant vehicles, e.g., culture medium with/without serum and phosphate buffered saline.

An Investigation on the Effects of Experimental Variables on Silver Nano Particles Produced by Electromagnetic Levitation Technique

In this study the effects of melt temperature and flow rate of cooling gas on the characteristics of silver nanoparticles have been studied. Transmission electron microscopy and dynamic light scattering techniques have been employed to monitor morphology and particle size of the product. Measurements reveal that higher melt temperatures and higher cooling gas flow rates can decrease particle size. Silver nanoparticles with an average particle size of 35 nm and specific surface of 18.489 m2/g have been obtained at a melt temperature of 1,130 °C with argon flow rate of 20 liters per minute.

Refractive Index Tailoring of Poly(methylmethacrylate) Thin Films by Embedding Silver Nanoparticles

Nanocomposite films of Poly (methylmethacrylate) with different concentration of silver nanoparticles were prepared by ex-situ method. Firstly, silver nanoparticles were obtained by reducing the aqueous solution of silver nitrate with sodium borohydride then Ag-PMMA films were prepared by mixing colloidal solution of silver nanoparticles with solution of polymer. Thin solid films were structurally characterized using UV-VIS spectroscopy and TEM. The appearance of surface plasmon resonance peak, characteristic of silver nanoparticles at 420 nm in UV-VIS absorption spectra of Ag-PMMA films confirms the formation of Ag-PMMA nanocomposite. TEM showed Ag nanoparticles of average size 8 nm embedded in PMMA matrix. Analysis of absorption and reflection data indicates towards the reduction in optical band gap and increase in refractive index of the resulting nanocomposite. The synthesized Ag-PMMA nanocomposite has been found to be more conducting than PMMA as ascertained using I-V studies. The decrease in band gap and increase in conductivity can be correlated due to the formation of localized electronic states in PMMA matrix due to insertion of Ag nanoparticles. The PMMA thin films with dispersed silver nanoparticles may be useful for nanophotonic devices.

Negative photoconductivity in silver nanocubes prepared by simple photochemical method

Silver nanocubes embedded in polyvinyl alcohol matrix have been synthesised by photoirradiation technique. The composite films are characterised by FESEM, XRD, UV-Visible absorption and photoluminescence. These show characteristics of silver nanoparticles with FESEM showing the cubic shape. The photoconductivity study of these films shows decrease in photocurrent with light irradiation. Such negative photoconductivity behaviour may be attributed to dominant scattering of electrons by excited surface plasmon polaritons in nanoscale.

Towards single-microorganism detection using surface-enhanced Raman spectroscopy

The identification and discrimination of microorganisms is important not only for clinical reasons but also for pharmaceutical clean room production and food-processing technology. Vibrational spectroscopy such as IR, Raman, and surface-enhanced Raman scattering (SERS) can provide a rapid ‘fingerprint’ on the chemical structure of molecules and is used to obtain a ‘fingerprint’ from microorganisms as well. Because of the requirement that a single bacterium cell and noble metal nanoparticles must be in close contact and the lack of a significant physical support to hold nanoparticles around the single bacterium cell, the acquisition of SERS spectra for a single bacterium using colloidal nanoparticles could be a challenging task. The feasibility of SERS for identification down to a single bacterium is investigated. A Gram-negative bacterium, Escherichia coli, is chosen as a model for the investigation. Because the adsorption of silver nanoparticles onto the bacterial cell is an exclusive way for locating nanoparticles close to the bacterium cell, the absorption characteristics of silver nanoparticles with different surface charges are investigated. It is demonstrated that the citrate-reduced colloidal silver solution generates more reproducible SERS spectra. It is found that E. coli cells aggregate upon mixing with silver colloidal solution, and this may provide an additional benefit in locating the bacterial cell under a light microscope. It is also found that a laser wavelength in the UV region could be a better choice for the study due to the shallow penetration depth. It is finally shown that it is possible to obtain SERS spectra from a single cell down to a few bacterial cells, depending on the aggregation properties of bacterial cells for identification and discrimination.