Varied Potentials of Aspergillus Species in Synthesis of Silver Nanoparticles

Synthesis of OA-Ag NPs: For the preparation of OA-stabilized Ag NPs [39], silver trifluoroacetate (0.4 g), OA (3.5 mL), and isoamyl ether (30 mL) were mixed in a 250 mL three-neck flask under argon. The mixture was heated at 160 °C for 30 min then cooled to room temperature by removing the heat source. The purification process was performed four times using excess polar solvent (ethanol) and centrifugation. The precipitated OA-Ag NPs were dispersed in

The association of metal nanoparticles and antibiotics is a very promising area of research. Silver nanoparticles are interesting when compared with silver ions due to their larger size, in turn, improves the capacity to react with several molecules. The bactericidal action of silver nanoparticles and amoxicillin was investigated using E. coli and silver nanoparticles of 20 nm in size (prepared by reducing an aqueous solution of AgNO3 with a freshly prepared aqueous ascorbic acid solution and ammonia). Microbiological tests

Silver salts have been used as a separation facilitator since 1944. In this early work, an aqueous solution of the silver salt AgNO3 at 50 wt% was used in the absorption and extraction of light olefins from

It is well established that polymers, as dielectric materials, are a good host matrices for encapsulation of metal nanoparticles like silver, gold, etc., as they act as reducing and capping agents and also supplied chemical and environmental stability

Nowadays, a large spectrum of the studies focus on nanoparticles. Silver nanoparticles (Ag-NPs) have a lot of application in many aspect from medicine and biotechnology to industry. Despite of the increasing studies on Ag-NPs, the mechanism, associated to their effects, especially probable toxicity on reproduction procedure, developmental process and offspring behavioral following this period, are not so clear. Therefore in the present study the effect of Ag-NPs exposure during gestational period on offspring's depression behavior was assessed. Thirty virgin female mice were divided into three groups (n= 10 for each group) including: one control and two experimental groups which one received low dose (0.2mg/kg) and the other received high

After completing my doctoral degree at the University of Louisville, I turned my focus to the surface chemistry of nanomaterials for preparing bioconjugates, a continuation of my work on surface chemistry on nanomaterials. In another work during the postdoctoral research period, I was able to publish a work on dielectrophoresis manipulation of metal nanoparticles to increase substantially the amount of frequency of collisions (by the factor of 101-103) of the metal nanoparticles with the surface of

Chemical synthesized nanoparticles raises certain toxicity issues that lead to development of eco-friendly methods to synthesize silver nanoparticles. Green synthesis of silver nanoparticles using plant extract is eco-friendly nanoparticle synthesis approaches (13). This is one step reaction as reducing and stabilization agents both are present in the plant extract. Silver nitrate and extract when mixed together forms light yellow coloured solution in starting that turns into dark brown solution later. The appearance of a dark-brown color in solution containing the extract and silver nitrate was a clear indication of the formation of AgNPs in the reaction mixture. Nanoparticle shape and size as observed by TEM reveled that these particles are not perfectly spherical but also have quasi-spherical, triangular and pentagonal shapes. Heterogeneous particles formation occurs due to rapid utilization of the capping molecules. Particles formed later are with less capping molecules and becomes thermodynamically unstable. These particles with less number of capping molecules then tends to minimize high surface energy and gets shape of a triangle or pentagonal having smooth angles (14, 15). XRD analysis and peak matching with similar AgNPs confirmed the crystalline structure of AgNPs. Two extra peaks present in the XRD spectra marked by star indicate the presence of biological moieties in the AgNPs (14). Hence, biological functional group involvement in

Fig. (1), shows the absorbance spectra for different gamma doses of PVA/Ag nanocomposite films (b to b4). In the UV region, all the samples showed absorption band at 200 nm, which is mainly assigned as transition between the Ag nanoparticles and poly(vinyl alcohol)[17]. No absorption in the wavelength range 350–800 nm was observed for both samples (b and b1) exposed to 0 KGy and 25 KGy. This is due to the time of reaction and the gamma irradiation energy is not sufficient to reduce all the AgNO3 particles to Ag nanoparticles. However, for the spectra of the samples (b2-b4) exposed to (50, 75 and 100 KGy) clearly indicate, a peak starts emerging at 427 nm. In addition, this peak intensity increases with increasing the γ irradiation

The characteristics of the disc surface affect the flow patterns generated on the film as well as the residence time of the reactants film. The effect of disc texture on particle characteristics is depicted in Figure 7 and Figure 8. It can be seen that using the grooved disc surface results in smaller particle size and narrower particle size distribution as compared to smooth disc surface. A narrow particle size distribution for the production of silver nanoparticles was achieved by Iyer et al.[43] using the grooved disc. The authors postulated that that the corrugated nature of the grooved disc promoted shear induced micromixing of the thin film on the disc at higher rotational speed. The efficient micromixing ensured that all the particles were exposed to the similar conditions to maintain a narrow size distribution [43]. Similar enhancement effects of grooved surfaces have been reported for styrene polymerisation in the SDR [9]. It has also been suggested in the literature that surface textures have the potential to suppress liquid channelling or rivulet flow compared to a smooth surface under identical conditions of liquid flowrate and liquid properties so that a higher wetted area is achieved [44]. Rivulet flow as opposed to film flow would result in larger average film thicknesses which may lead to detrimental performance, especially under strictly laminar flow conditions (i.e. where any surface wave-induced turbulence is absent). Thus, the intensifying effects of the

Nanotechnology plays an important role in the fabrication of different nanoparticles that can exhibit novel antimicrobial properties [14]. The nano-scale of metals play roles in understanding the ability to manipulate biological processes which will be the central theme for present biomedical and biological issues that need a nanoscience or nanotechnology approach [15]. Shahverdi et al [14]

Nanoparticles are widely researched because of their size dependent properties that progressively differ from their bulk formations. Nano, meaning these particles are measured to be ~100 nm or less, are structures where the majority of the atoms are located at the surface of the particle. This gives nanoparticles a high surface area to volume ratio. In comparison to their bulk counterparts, when materials are in the nano scale, the physical and chemical properties of these different materials tend to stray from the norm. These changes allow nanoparticles to be effective in several fields of science and engineering based research, for example, chemical catalysis. These size dependent properties will be analyzed through three experiments: (1) absorption and fluorescence emmission of CdSe nanocrystals, (2) Plasmon resonance of metal nanocrystals, and (3) Raman scattering and surface enhanced Raman scattering.

AL-Thabaiti et al.[ ], reported the PVA/Ag (nacre-like) nanocomposite films were built during the reduction of Ag+ ions in to Ag0 by tyrosine. Also, investigated the surface plasmon resonance band at 425 to 475 nm due to the formation of Ag nanoparticles. On the other, recorded a broad SRP absorption band centered at 450 nm in presence of shape-directing CTAB. Then, studied the effect of both the PVA and CTAB on the formation of the Ag nanopaerticles and they found the PVA, is better capping and protecting agent than CTAB, is very effective to inhibit the agglomeration of particles. Also, they found that there is no effect on the position and nature of the surface plasmon resonance band with the increasing concentrations of the PVA. Badr et al. [ ], studied the effect of Ag concentration (1.14, 2.1, 3.2, 3.6, 4.2, 4.8, and 5.4

In recent times, infectious diseases continue to pose a major healthcare issue in developing countries making it imperative to develop logical solutions for robust and rapid diagnosis and treatment of these infections. Traditional techniques suffer from limitations, including laborious specimen processing, bulky instrumentation, and slow result readout. In view of the urgency for sensitive, specific, robust and rapid diagnostics, numerous advancements have been made in the area of nanotechnology to aid this effort. This methodical analysis will focus on the recent developments in nanotechnology-based diagnostics of bacterial pathogens in developing countries. The aim of this review article is to describe the

Preparation, characterization, and physical properties of a nanostructured materials of silver (nanoparticles and nanocomposites) have been the subject of various researcher in many scientific laboratories during the past years for many studies and it has been also established that size, stability, color, shape, and properties depend on the method of preparation (radiation, photochemical, electrochemical, and chemical) as well as experimental factors such as [reactants], [stabilizer and/or capping agents], temperature, order of mixing of reactants, presence of stabilizers and capping agents and even on the addition rate of reducing agents [1–12].

In the present work, PVA-Ag nanocomposite films with thickness 0.18 mm, constant silver content (0.4 wt. %) and with different time of reaction (0.1, 3, 5, 7, 9 h) were prepared by chemical reduction method. Structure, surface topology, photoluminescence and electrical properties of PVA-Ag nanocomposite were studied using x-ray diffraction (XRD), electrometer, atomic force microscope (AFM) and photoluminescence (PL) spectroscopy were used to characterize the prepared nanocomposites. X-ray patterns showed the existence of Ag-nanoparticles within the PVA polymeric matrix with face centered cube (FCC) phase. It was found that the PL intensity for all samples increases, while the root mean square (rms) roughness decreases as the time of reaction is increased. Current-voltage characteristics were analyzed to explore carrier transport mechanisms in Ag-PVA nanocomposite and the results showed that there is an improvement in the electrical conductivity of the PVA-Ag films and Frank-poole emission is the prevailing transport mechanism for all samples.