Silver NP Research Articles

Detecting the antibacterial activity of green synthesized silver (Ag) nanoparticles functionalized with ampicillin (Amp)

In the current study, synthesis and characterization of silver nanoparticles (AgNPs) before and after functionalization with ampicillin antibiotic and their application as anti-pathogenic agents towards bacteria were investigated. AgNPs were synthesized by a green method from AgNO3 solution with glucose subjected to microwave radiation. Characterization of the nanoparticles was conducted using UV-Vis spectroscopy, scanning electron microscopy (SEM), zeta potential determination and Fourier transform infrared (FTIR) spectroscopy. From SEM analysis, the typical silver nanoparticle particle size was found to be 30 nm and Zeta potential measurements gave information about particle stability. Analysis of FTIR patterns and UV-VIS spectroscopy confirmed the production of nanosilver particles. The activity of produced silver NP was tested against three pathogens (Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii) in both liquid and solid growth medium. AgNPs presented potential antibacterial activity, against tested bacteria. Ag and Ag-AMP nanoparticles were detected to have penitent antimicrobial. The optical density (OD) of the culture solution and measuring zones of inhibition were used to monitor the growth of bacteria in liquid and solid growth medium respectively

Detecting the antibacterial activity of green synthesized silver (Ag) nanoparticles functionalized with ampicillin (Amp)

In the current study, synthesis and characterization of silver nanoparticles (AgNPs) before and after functionalization with ampicillin antibiotic and their application as anti-pathogenic agents towards bacteria were investigated. AgNPs were synthesized by a green method from AgNO3 solution with glucose subjected to microwave radiation. Characterization of the nanoparticles was conducted using UV-Vis spectroscopy, scanning electron microscopy (SEM), zeta potential determination and Fourier transform infrared (FTIR) spectroscopy. From SEM analysis, the typical silver nanoparticle particle size was found to be 30 nm and Zeta potential measurements gave information about particle stability. Analysis of FTIR patterns and UV-VIS spectroscopy confirmed the production of nanosilver particles. The activity of produced silver NP was tested against three pathogens (Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii) in both liquid and solid growth medium. AgNPs presented potential antibacterial activity, against tested bacteria. Ag and Ag-AMP nanoparticles were detected to have penitent antimicrobial. The optical density (OD) of the culture solution and measuring zones of inhibition were used to monitor the growth of bacteria in liquid and solid growth medium respectively

In vitro assessment of solubility and bioavailability of vinblastine using nanoparticulated formulations

Catharanthus roseus (Madagascar periwinkle) is an ornamental plant belonging to the Apocynaceae family. Besides its importance as an ornamental plant, its interest today is centered on its capacity to biosynthesize a great variety of terpenoid indole alkaloids (TIAs) which are valued highly due to their wide spectrum of pharmaceutical application. Among these, vinblastine and vincristine are of particular importance because of their wide use in cancer chemotherapy. Vinblastine can have extensive use for the treatment of lung cancer, breast cancer, head and neck cancer, and testicular cancer. It is also used to treat Langerhens cell histocytosis.This study was done to assess the solubility of vinblastine. The extracted crude vinblastine was encapsulated with nanoparticles and solubility was determined at different pH range.Silver Nanoparticles was synthesized using reduction method, LDH was synthesized by Co-precipitation method while MMT was purchased from Sigma-Aldrich.Silver NP formulation showed maximum solubility at pH 10.4 and least at pH 6. In case of Layered Double Hydroxide (LDH) Nanoparticles and Montmorillonite nanoparticles (MMT) maximum solubility was obtained at pH 7 and pH 8.6, respectively. The increased solubility range of the drug with various nanoparticles formulation will enhance the bioavailability of the drug at physiological pH.This study shows that formulation of NP-TIA’s has significant potential in the field of chemotherapy and drug delivery. How to view point the article : Singh, Alok, Jan, Manar W. and Naskar, Jishnu (2016). In vitro assessment of solubility and bioavailability of vinblastine using nanoparticulated formulations. Internat. J. Plant Protec., 9(1) : 199-203.

Profiling and Imaging Ion Mobility-Mass Spectrometry Analysis of Cholesterol and 7-Dehydrocholesterol in Cells Via Sputtered Silver MALDI.

Profiling and imaging of cholesterol and its precursors by mass spectrometry (MS) are important in a number of cholesterol biosynthesis disorders, such as in Smith-Lemli-Opitz syndrome (SLOS), where 7-dehydrocholesterol (7-DHC) is accumulated in affected individuals. SLOS is caused by defects in the enzyme that reduces 7-DHC to cholesterol. However, analysis of sterols is challenging because these hydrophobic olefins are difficult to ionize for MS detection. We report here sputtered silver matrix-assisted laser desorption/ionization (MALDI)-ion mobility-MS (IM-MS) analysis of cholesterol and 7-DHC. In comparison with liquid-based AgNO3 and colloidal Ag nanoparticle (AgNP), sputtered silver NP (10-25 nm) provided the lowest limits-of-detection based on the silver coordinated [cholesterol + Ag](+) and [7-DHC + Ag](+) signals while minimizing dehydrogenation products ([M + Ag-2H](+)). When analyzing human fibroblasts that were directly grown on poly-L-lysine-coated ITO glass plates with this technique, in situ, the 7-DHC/cholesterol ratios for both control and SLOS human fibroblasts are readily obtained. The m/z of 491 (specific for [7-DHC + (107)Ag](+)) and 495 (specific for [cholesterol + (109)Ag](+)) were subsequently imaged using MALDI-IM-MS. MS images were co-registered with optical images of the cells for metabolic ratio determination. From these comparisons, ratios of 7-DHC/cholesterol for SLOS human fibroblasts are distinctly higher than in control human fibroblasts. Thus, this strategy demonstrates the utility for diagnosing/assaying the severity of cholesterol biosynthesis disorders in vitro.

Low-temperature Cu-to-Cu bonding using silver nanoparticles stabilised by saturated dodecanoic acid

We developed a new method to prepare silver NP paste that can be used as a Cu-to-Cu bonding material under an additional pressure of 10MPa. This new paste consists of a high concentration of uniform silver NPs with a thin layer of dodecanoate coated on the surface. Shear strengths indicate that the silver NP paste prepared with our method could serve as a bonding material in electronic packaging and interconnections. The microstructure of the interface between the silver and the copper substrate was examined using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Based on this analysis, a metallic bond is formed at the interface between the sintered Ag layer and both sides of the joint when bonding Cu pads above 250°C.

Up-conversion enhancement in Er3 +-Ag co-doped zinc tellurite glass: Effect of heat treatment

The melt quenching method was used to synthesize the Ag0 nanoparticles and Er3+ ions co-doped zinc tellurite glass. The glasses were characterized by differential thermal analyzer, UV–VIS-IR absorption, photoluminescence spectroscopy and TEM imaging. Heat treatment at different annealing time intervals above the glass transition temperature was applied to reduce the Ag+ ions to Ag0 NPs. The influence of heat treatment on structural and optical properties is examined. Intense and broad up-conversion emissions of silver are recorded in the visible region. Up-conversion luminescence spectra revealed three major emission peaks at 520, 550 and 650nm originating from 2H11/2, 4S3/2 and 4F9/2 levels, respectively. An efficient enhancement in visible region is observed for samples containing silver NPs. The absorption plasmon peaks are evidenced around 560 and 594nm. The effect of localized surface plasmon resonance and the energy transfer from the surface of silver NP to trivalent erbium ions are described as the sources of enhancement.

Silver nanoparticles modified nanocapsules for ultrasonically activated drug delivery

Novel ultrasound-sensitive nanocapsules were designed via layer-by-layer assembly (LbL) of polyelectrolytes for remote activated release of biomolecules/drug. Nanocapsules embedded with silver nanoparticles in the walls were synthesized by alternate assembly of poly(allylamine hydrochloride) (PAH) and dextran sulfate (DS) on silica template followed by nanoparticle synthesis and subsequent template removal thus yielding nanocapsules. The silver NPs were synthesized in situ within the capsule walls under controlled conditions. The nanocapsules were found to be well dispersed and the silver NPs were evenly distributed within the shell. FITC-dextran permeated easily into the capsules containing silver NP's due to the pores generated during the formation of NP's. When the loaded nanocapsules were sonicated, the presence of the silver NPs in the shell structure led to rupturing of the shell into smaller fragments thus releasing the FITC-dextran. Such nanocapsules have the potential to be used as drug delivery vehicles and offer the scope for further development in the areas of modern medicine, material science, and biochemistry.

Modelling of optical absorption of silver NP’s produced by UV radiation embedded in mesostructured silica films

Hexagonal mesostructured films containing silver ions were obtained by sol–gel method. Brij 58 was used to produce channels into the film, which house these ions. The films were exposure to UV radiation to produced silver metallic nanoparticles. The presence of the metallic nanoparticles was determined by infrared spectroscopy and optical absorption. Besides, these nanoparticles and core–shell structures of silver–silver oxide nanoparticles were identified by high-resolution transmission electronic microscopy. From these measurements, the obtained size range for silver nanoparticles was 6.1 nm. The absorption spectrum located at 440 nm was modelled and well fitted with the Gans theory considering refractive index higher than the one coming from host matrix. This index is explained because the silver oxide shell modifies the local surrounding medium of the metallic nanoparticles.

Surface plasmon absorption study of silver NP thin film containing 2,2′-bipyridine

Abstract The fine tuning of localized surface plasmon resonance (LSPR) of Ag-NP film containing 2,2′-bipyridine (bipy), self-assemble at room temperature when solution cast from dispersions on the glass substrate is described. The suspension of Ag colloid was prepared via polyol reduction stabilization using microwave radiations. SEM, EDS study reveals that NPs are uniform in size and reduced to metallic Ag. The cooperative SPR (approx. at 418 nm) of 2D assembly has been depressed due to 2,2′-bipyridine ligand structured around Ag-NPs showing red shift (456 nm). The cooperative resonance can be controlled by varying impingement time of microwave power on film. As the impingement time increased co-operative resonance begins blue shift due to increase in the cooperative interaction between Ag-NPs via decomposition of bipyridine. The co-operative resonance of 2D assembly that is at 418 nm was regained after complete removal of 2,2′-bipyridine at higher temperatures thus showing tunable LSPR properties of Ag-Bipy nanostructure. Opposite type of behavior that is strong damping were seen in case of Ag-NPs in solution phase. Temperature dependent viscosity characteristics suggest that Plasmon damping can be attributed to decrease in viscosity of Ag-NP solution.

Structural Property Effect of Nanoparticle Agglomerates on Particle Penetration through Fibrous Filter

Most filtration studies have been conducted with spherical particles; however, many aerosol particles are agglomerates of small primary spheres. Filtration efficiency tests were conducted with silver NP agglomerates, with the agglomerate structure controlled by altering the temperature of a sintering furnace. The mobility diameter and mass of the silver NP agglomerates were measured using a differential mobility analyzer together with an aerosol particle mass analyzer. From these measurements, it was found that the fractal-like dimension, D fm, varied from 2.07 to 2.95 as the sintering temperatures was increased from ambient to 600°C. The agglomerates were essentially fully coalesced at 600°C allowing direct comparison of the filtration behavior of the agglomerate to that of a sphere with the same mobility diameter. Other agglomerate properties measured include the primary diameter, the agglomerate length and aspect ratio, and the dynamic shape factor. Agglomerate filtration modeling with no adjustable parameters has been investigated in terms of diffusion, impaction, and interception. The model results agree qualitatively with the experimental results in the particle size range of 50 to 300 nm. The results indicated that the larger interception length of agglomerates is responsible for the smaller penetration through a fibrous filter in comparison to spherical particles with the same mobility diameters.