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Synthesis of gold nanoparticles using renewable Punica granatum juice and study of its catalytic activity
Shib Shankar Dash,Braja Gopal Bag
Applied Nanoscience , 2013, DOI: 10.1007/s13204-012-0179-4
Abstract: Punica granatum juice, a delicious multivitamin drink of great medicinal significance, is rich in different types of phytochemicals, such as terpenoids, alkaloids, sterols, polyphenols, sugars, fatty acids, aromatic compounds, amino acids, tocopherols, etc. We have demonstrated the use of the juice for the synthesis of gold nanoparticles (AuNPs) at room temperature under very mild conditions. The synthesis of the AuNPs was complete in few minutes and no extra stabilizing or capping agents were necessary. The size of the nanoparticles could be controlled by varying the concentration of the fruit extract. The AuNPs were characterized by surface plasmon resonance spectroscopy, high resolution transmission electron microscopy, fourier transform infrared spectroscopy and X-ray diffraction studies. Catalytic activity of the synthesized colloidal AuNPs has also been demonstrated.
Synthesis, Characterization and Catalytic Property of Polymer Protected Gold and Silver Nanoparticles  [cached]
Baigaziyeva E.K.,Kudaibergenov S.E.,Yesmurzayeva N.N.,Nurakhmetova Zh.A.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2013,
Abstract: Gold (AuNPs) and silver (AgNPs) nanoparticles protected by hydrophilic polymers were prepared by “one-pot” synthetic protocol. Absorption spectra, size, morphology and structure of obtained nanoparticles were investigated by UV-Vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The catalytic activity of polymer-protected AuNPs and AgNPs supported on the surface of aluminum oxide was evaluated with respect to decomposition of hydrogen peroxide.
Polyethylene glycol functionalized gold nanoparticles: the influence of capping density on stability in various media
Joanne Manson,Dhiraj Kumar,Brian J. Meenan,Dorian Dixon
Gold Bulletin , 2011, DOI: 10.1007/s13404-011-0015-8
Abstract: Thiol-terminated polyethylene glycol (PEG) is commonly used to functionalize the surface of gold nanoparticles (AuNPs) in order to improve their in vivo stability and to avoid uptake by the reticular endothelial system. Although it has been reported that AuNPs functionalized with tethered PEG are stable in biological media, the influence of chain density remains unclear. This study investigates the influence of PEG capping density on the stability of washed and dried AuNPs in: water, phosphate-buffered saline solution (PBS), phosphate-buffered saline solution containing bovine serum albumin (PBS/BSA), and dichloromethane (DCM). PEG coating had a dramatic effect on stability enabling stable suspensions to be produced in all the media studied. A linear relationship was observed between capping density and stability in water and DCM with a somewhat lower stability observed in PBS and PBS/BSA. A maximum PEG loading level of ~14 wt.% was achieved, equivalent to a PEG surface density of ~1.13 chains/nm2.
Synthesis of non-spherical gold nanoparticles
M. Tréguer-Delapierre,J. Majimel,S. Mornet,E. Duguet,S. Ravaine
Gold Bulletin , 2008, DOI: 10.1007/BF03216597
Abstract: This article provides an overview of current research in the area of anisotropic gold nanoparticles. We begin by outlining key properties that they possess; we then describe how to control their morphology. Some of the most innovative synthetic strategies are highlighted together with an emphasis on recent results from our laboratories as well as future perspectives for anisotropic gold nanoparticles as novel materials.
Ponnuswamy Renuka Devi et al.
International Journal of Pharmaceutical Sciences and Research , 2012,
Abstract: The unusual physio and chemical properties of gold nanoparticles are found to have more advantage in the field of medicine, diagnostics and biosensors. In the present document, it is reported that Justicia gendarussa leaf extract mediated synthesis of gold nanoparticles by the reduction of gold ions. Three different phytochemical fractions were prepared from methanolic leaf extract by liquid-liquid extraction method using immiscible solvents. The total polyphenols, flavonoids and electron donating capacity (DPPH assay) of each phytochemical fraction was analyzed. The 1mg/ml of diethyl ether phytochemical fraction produced more gold nanoparticles within 15 minutes when exposed to 10ml of 0.5mM chloroauric acid compared to chloroform and ethyl acetate phytochemical fractions. The structural characteristics of diethyl ether phytochemical fraction synthesized gold nanoparticles were characterized by UV-visible spectroscopy, Dynamic light scattering, Transmission electron microscopy, X-ray diffraction and Fourier transform-infrared spectroscopies. These biosynthesized gold nanoparticles showed surface plasmon resonance band at 536nm in UV-visible spectrum. The size of the gold nanoparticles ranged from 20 to 42nm and 62 to 88nm with spherical, triangle, truncated triangle and hexagonal shapes. From the Fourier transform-infrared spectra of diethyl ether phytochemical fraction and synthesized gold nanoparticles, the possible functional group involved in gold ions reduction and capping of gold nanoparticles were identified. The stability of gold nanoparticles for 5 month period and at different pH range (5-10) was analyzed by observing the changes in surface plasmon resonance of gold nanoparticles. Moreover, the diethyl ether phytochemical fraction showed no cytotoxicity up to 100μg/ml in RAW 264.7 cell line .
Preparation, Characterization and Catalytic Activity of Gold Nanoparticles Stabilized by Hydrophilic Polymers  [cached]
Kudaibergenov S.,Baigaziyeva E.,Tatykhanova G.S.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2012,
Abstract: Optical properties, structure, size and morphology of colloidal gold nanoparticles (AuNPs) stabilized by a series of hydrophilic polymers possessing nonionic, anionic, cationic and amphoteric nature were characterized by visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD) and scanning electron microscopy (SEM), transmission electron microscopy (TEM). The polymer-protected AuNPs were prepared by “one-pot” synthetic protocol. The kinetics of formation of AuNPs was determined. The influence of the molecular weight (Mw) of polymers and concentration of AuNPs on the size of AuNPs was shown. The catalytic activity of polymer-protected AuNPs with respect to hydrogenation of 4-nitrophenol was studied. High conversion degree of 4-nitrophenol to 4-aminophenol was evaluated by visible spectroscopy.
Facile Synthesis, Characterization and Catalytic Function of Gelatin Stabilized Gold Nanoparticles  [PDF]
Zulfiqar A. Tagar,Sirajuddin,Najma Memon,Muhammad S. Kalhoro
Pakistan Journal of Analytical and Environmental Chemistry , 2012,
Abstract: In the present investigation, we report a new one phase, one pot method for synthesis of 3.5 ± 0.7 nm average sized gelatin capped gold nano particles (Gel-AuNPs) using strong reductant NaBH4 in aqueous system at room temperature. Size controlled Gel-AuNPs were characterized by UV-Visible, STEM, XRD, DLS and FT-IR. Spherical Gel-AuNPs showed excellent catalytic activity for reduction of three differently charged dyes eosin B (EB), methylene blue (MB) and rose bengal (RB) in the presence of NaBH4. The study revealed that 100% reduction of EB, MB and RB dyes was carried out in just 150 sec. The developed catalyst was easy to recover and capable to be reused three times. The process of reduction rate and kinetics of dyes was monitored using UV-Visible spectrophotometer. A plot of lnC Vs time (sec) showed that reaction follows the first order kinetics. Rate constant (K) was determined for EB, MB and RB reduction at 10 μM, which was found as 2.735 x10-2 sec-1, 2.738 x 10-2 sec-1 and 2.55 x 10-2 sec-1, respectively. The study revealed that catalytic reduction of dyes by Gel-AuNPs in aqueous medium is environmental friendly in terms of recovery of catalyst, is exceptionally fast and hence extremely economical.
Synthesis of Gold-Palladium Bimetallic Nanoparticles and Surface Catalytic Activity in Suzuki Coupling Reactions Using in FTIR Spectroscopy
American Journal of Materials Science , 2012, DOI: 10.5923/j.materials.20120203.09
Abstract: Colloidal bimetallic gold core palladium shell nanoparticles were prepared by wet chemical method, in which Au(III) and Pd(II) ions in an aqueous solution in the presence of a cationic surfactant, Cetyltrimethylammonium bromide (CTAB). The structure and composition of the metallic nanoparticles were characterized by UV-Vis, HRTEM, SEM-EDX, XRD, XPS and FTIR. The catalytic activities of nanoparticles are tested on the surface chemical characterization study of Cetyltrimethylammonium bromide supported Au-Pd bimetallic nanoparticle catalyst, hereafter named Au-Pdnp, is reported. Such a catalyst was developed for the Suzuki coupling reaction and found excellent catalytic activity. Here we describe the catalytic performance and the FTIR studies provide proof of the mode of binding that occurs in the Palladium nanoparticle surface for the first time and also confirms the mechanism of the Suzuki reaction.
In Vivo Study of Spherical Gold Nanoparticles: Inflammatory Effects and Distribution in Mice  [PDF]
Hui Chen, Alisha Dorrigan, Sonia Saad, Dominic J. Hare, Michael B. Cortie, Stella M. Valenzuela
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0058208
Abstract: Objectives Gold nanoparticles (AuNPs) of 21 nm have been previously well characterized in vitro for their capacity to target macrophages via active uptake. However, the short-term impact of such AuNPs on physiological systems, in particular resident macrophages located in fat tissue in vivo, is largely unknown. This project investigated the distribution, organ toxicity and changes in inflammatory cytokines within the adipose tissue after mice were exposed to AuNPs. Methods Male C57BL/6 mice were injected intraperitoneally (IP) with a single dose of AuNPs (7.85 μg AuNPs/g). Body weight and energy intake were recorded daily. Tissues were collected at 1 h, 24 h and 72 h post-injection to test for organ toxicity. AuNP distribution was examined using electron microscopy. Proinflammatory cytokine expression and macrophage number within the abdominal fat pad were determined using real-time PCR. Results At 72 hours post AuNP injection, daily energy intake and body weight were found to be similar between Control and AuNP treated mice. However, fat mass was significantly smaller in AuNP-treated mice. Following IP injection, AuNPs rapidly accumulated within the abdominal fat tissue and some were seen in the liver. A reduction in TNFα and IL-6 mRNA levels in the fat were observed from 1 h to 72 h post AuNP injection, with no observable changes in macrophage number. There was no detectable toxicity to vital organs (liver and kidney). Conclusion Our 21 nm spherical AuNPs caused no measurable organ or cell toxicity in mice, but were correlated with significant fat loss and inhibition of inflammatory effects. With the growing incidence of obesity and obesity-related diseases, our findings offer a new avenue for the potential development of gold nanoparticles as a therapeutic agent in the treatment of such disorders.
Study of Catalytic Activity of the New Nanohybrid Material Based on Gold Nanoparticles and 1,4-bis(Terpyridine-4'-yl)Benzene  [cached]
Manzheliy E.A.,Zyk N.V.,Majouga A.G.,Beloglazkina E.K.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2012,
Abstract: The paper describes the synthesis of composite material consisting of 1,4-bis(terpyridine-4'-yl)benzene microcrystals and gold nanoparticles with an average size of ~15 nm adsorbed on their surfaces. The nanohybrid material is obtained by the deposition of pre-synthesized nanoparticles on the surface of the organic compound. Mass content of gold in the obtained material is determined by the thermogravimetrical analysis. Catalytic reduction of para-nitrophenol is spectrophotometrically studied.
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