Engineering and Technology Journal

The study aims to investigate the effects of silver nanoparticles (Ag NPs) on the seminiferous tubules in Albino rats. Several in vitro studies have been performed in different cell models, using various nanoparticles. Pure and spherical AgNPs with an average size of 30 nm, was injected into two groups of male albino rats (6 rats for each group) in different doses. Histopathological changes in testis tissues were showed a harmful effect of the silver nanoparticles, manifested by reducing the number of spermatogenic cells, and a decrease in the number of leyidg´s cells (group 1), and hypotrophy in seminiferous and enlargement in interstitial spaces in group 2.

In this present work we have synthesized stable silver
nanoparticles (Ag-NPs) by chemical reduction with aqueous solutions of
silver nitrate (i) propylene glycol (ii) glycerin as reducing agents and guar
gum as a stabilizer. The reaction were done at room temperature and at
pH=8. Systematic characterizations of the Ag-NPs were done using UV-Vis,
zeta potential analysis, X-Ray diffraction (XRD), AFM and SEM which
reveal stable Ag-NPs. These measurements indicate that the particles are
mostly spherical in shape. The UV-Vis spectra of the result solution of Ag-
NPs show an absorption peak at 412 nm and 424 nm for using propylene
glycol and for using glycerin respectively. These color occurring due to
Surface Plasmon Resonance (SPR). The SEM measurements gave a particle
size of 40 -70 nm. Nano silver showed stability for long periods of time to
more than nine months, and this can be an economical and effective way for
wide scale synthesis of Ag-NPs which applicable for various medical
therapies.

In this present study, Pulsed Laser Ablation in Liquid (PLAL) experiment setup for synthesis colloidal solution of silver-NPs. The laser system was used in this study, a (Nd-YAG) nanosecond laser system with optimal pulse duration of 10 ns and repetition rate 1-6 Hz. The Laser wavelengths were: 1064 nm, 532 nm and 355 nm. The spot size of the laser beam on the surface of metal plate was varied in the range of 1.4-1.5 mm in diameter by changing the distance between the focusing lens and the metal plate.The ablation process was typically done for 1 minute. The average particle size has been characterized by TEM, SEM and UV-Vis investigation. From morphologyresults for colloidal silver nanoparticles images were spherical shape and average size of the particles is 55-60 nm at wavelength (λ =1064 nm), average size of the particles is 35-40 nm at(λ =532 nm) and average size of the particles is 28 nm at(λ =355 nm).

The effect of indirect use of nanosilver particles (AgNPs) was studied for control water molds infection on Bunne eggs during incubation period in the hatchery. This effect was studded with different concentrations of nanosilver-coated natural zeolite (0.5,1and 2 % AgNPs) and these concentrations were compared with unmodified natural zeolite as water filter in semi-circulatory incubation system. All incubators were inoculated with water molds-infected Bunne eggs for testing the effect of AgNPs on inhibition of fungal infection. Dead and infected eggs were removed periodically ,the efficacy of the filters was assessed by estimation the survival rates from fertilization to accomplishment of the yolk-sac absorption stage. Survival rate was increased about 5.3% (filters with 0.5% AgNPs) from fertilization to larvae compared to control (P<0.05).The additional option of active carbon (absorbent media) along with AgNP-coated zeolite filters caused an increase of about 13.5% in the survival rate for the larval stage (P<0.05).No infection with water mold were observed in the incubators during the incubation period in the incubators with water supply from filters with AgNP-coated zeolite in contrast to the control group with about 12% water mold infection. The end results enhanced that the indirect usage of AgNPs in the aforementioned filters were significantly effective for control water mold infections on semi-circulation system for incubation of Bunne’s eggs, making them a candidate for exchange the chemical reagents currently used in eggs incubation in hatchery system. The indirect use of nanosilver materials for the disinfection of water for eggs incubation was applied for the first time in fish hatchery in Iraq.

In this work, Silvernanoparticles prepared by arc discharge method in deionized water byapplying stablized direct current between two silver rods which are submerged in deionized waterat room temperature without any heat exchanger,vacuum equipment and gas handling equipment. During electrical discharge the temperature between electrodes can reach several thousand Celsius degrees. This leads to etch of silver electrodes in deionized water, silver vapor condensed in water creats a stable silver aqueous suspension.
The silver nanoparticles were characterized by UV-Visiblephotometer, X-Ray Diffraction (XRD), and Atomic Force MicroscopeAFM. The optical absorption measurement showsthat the spectrum exhibits a Plasmon absorption band at ~ 400 nm which is the characteristic of silver nanoparticles.
X-Ray Diffraction of the resulting NPs indicated that the particles had a crystalline structureand the average particle size determined from AFM, is about 78.75 nm.

Silver nanowires (Ag NWs) have been attracted much attention in recent years .view of the extensive its use in various fields. Ag NWs were successfully prepared by two steps firstly electrochemical method and heating secondly silver nanoparticles colloidal solution at different temperature. The optical results show that the position of the plasmon absorption peak depends on the particle size and shape and the adsorption of surfactant to the particle surface. It was noticed that the plasmon absorption peak shifts toward shorter wavelengths (blue shift) as increased temperature.SEM result appeared that silver nanoparticles transformed to Silver nanowires by heating. XRD results explained that the intensity of peak at 64.46° was increased as heating increase much higher at 38.18° which indicted wire growth . The results zeta potential showed that all samples preparation shown across all the zeta potential tests were negative .

We have developed surface-enhanced Raman spectroscopysubstratecomposed of antibody-conjugated silver nanoparticles as a functional nanoprobe. In this study, we synthesized silver nanoparticles with the pMBA linker for binding to antibody Herceptin and analyzed the binding of Herceptin to silver nanoparticles by Fourier Tranform Infrared (FT-IR). Our results clearly showed that a spherical shape of silver nanoparticles with a diameter of 50 µm has been performed. Furthermore, the obtained SERS probe apparently indicated that the intensity of antibody-conjugated silver nanoparticles as a SERS sensitive probe is increased by an enhancement factor of 105.

Silver nanoparticles have found tremendous applications in the field of diagnostics and therapeutics. This work was aimed to study the antioxidant activity of Ag nanoparticles in water by scavengers the free radicals produced by radiation. The antioxidant properties of silver nanoparticles prepared by wire explosion technique have been evaluated using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay. Ag nanoparticles were characterized by UV-Visible absorption and the results showed surface Plasmon resonance absorption peaks around 397nm. The nanoparticle average size and its size distribution were determinate by Atomic Force Microscopy (AFM). The results showed that the absorption intensity varying systematically with increasing silver nanoparticles concentration with certain limits. So Ag nanoparticles were found to have significant antioxidant capacity and thus can be used as potential radical scavenger against deleterious damages caused by the free radicals.

Silver and gold nanoparticles were prepared by using nanosecond pulsed laser ablation. Ablation of pure metal targets (Ag and Au) for nanoparticle colloidal production was studied in de-ionized water. The optical properties were studied with Ultraviolet- Visible (UV-Vis) spectrophotometer. The spectra reveal sharp peaks due to surface plasmon absorption peaks at 405 nm and 523 nm for Ag and Au respectively. The size and shape of nanoparticles was investigated by Transmission Electron Microscope (TEM). Spherical shapes with average diameters of 10 nm and 6 nm for silver and gold nanoparticles were found respectively.

In this research we study the effect of different extracts of Teucrium polium (cold water, hot water and alcohol extraction), effect of silver nanoparticles and the combination effect of Teucrium polium extracts with silver nanoparticles against different pathogenic microorganisms Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus volgaris, Staphylococcus aureus, Streptococcus and Candida albicans. The results showed that the effect of cold water extract on microbial activity only inhibited the growth of P. aeruginosa. In case of hot water extract there is no effect on any type of microorganisms used in this study unlike the ethanolic extract it is affect on the growth of all microorganisms used except P. volgaris and E. coli. In the using of silver nanoparticles it inhibits the growth of all the microorganisms used in this research but in different ratios. In case of combination the effect will increase with assistant of silver nanoparticles except in P. aeruginosa and K. pneumonia the effect of silver nanoparticles alone is higher

In this work, antimicrobial potential of silver nanoparticles synthesized from extract of Myrtus communis on different pathogenic bacteria and yeast was investigated. 10 mL of extract was mixed with 90 mL of 2 mM aqueous AgNO3 and heated at 70 °C for 3 min. A change from greenish to dark brown color was observed. Characterization using UV-VIS spectrophotometery and X- ray diffraction analysis were performed. The UV-Vis spectral analysis showed silver surface plasmon resonance band at 425 nm. X- ray diffraction showed that the particles were crystalline in nature with face centered cubic structure (FCC) of the bulk silver with broad beaks at 38.50° and 44.76°. Antimicrobial activity against six microorganisms was tested using well diffusion method. The synthesized silver nanoparticles efficiently inhibited various pathogenic organisms in a dose-dependent manner was more pronounced against Gram-positive bacteria than Gram-negative bacteria. The approach of green synthesis seems to be cost effective, eco-friendly and easy alternative to conventional methods of silver nanoparticles synthesis. The powerful bioactivity demonstrated by the synthesized silver nanoparticles leads towards the clinical use as antimicrobial.