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Pin Oak (Quercus palustris) Leaf Extract Mediated Synthesis of Triangular, Polyhedral and Spherical Gold Nanoparticles  [PDF]
Jonathan D. Judy, N. V. K. V. Prasad Tollamadugu, Paul M. Bertsch
Advances in Nanoparticles (ANP) , 2012, DOI: 10.4236/anp.2012.13011
Abstract: Fabrication of phytogenic metal nanoparticles is a developing area of nanobiotechnology which has economic and potentially eco-friendly advantages over conventional chemical and physical synthesis methods. We report the synthesis of anisotropic gold nanostructures using a phytoextract from the leaves of the pin oak tree, Quercus palustris. We used 2.5%, 5%, and 10% m/v extract concentrations to determine the importance of pin oak phytoextract concentration on the properties of the nanomaterials synthesized. Characterization of the resulting nanomaterials revealed that the concentration of the phytoextract is a key factor controlling the size and relative frequency of shapes the gold nanostructures formed. TEM micrographs demonstrate that triangular, spherical, and polyhedral gold nanostructures were formed in all treatments, although UV-Vis spectra indicated that the formation of fewer nanostructures in the 2.5% m/v phytoextract treatment We found that anisotropic nanostructures are formed at the highest concentrations in the preparation using 10% m/v phytoextract. UV-Vis, TEM, and DLS data indicate that the 5% m/v phytoextract results in the synthesis of the smallest sized nanoparticles.
Gold and silver nanoparticles from Trianthema decandra: synthesis, characterization, and antimicrobial properties
Geethalakshmi R, Sarada DV
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S36516
Abstract: ld and silver nanoparticles from Trianthema decandra: synthesis, characterization, and antimicrobial properties Original Research (2015) Total Article Views Authors: Geethalakshmi R, Sarada DV Published Date October 2012 Volume 2012:7 Pages 5375 - 5384 DOI: http://dx.doi.org/10.2147/IJN.S36516 Received: 30 July 2012 Accepted: 24 August 2012 Published: 09 October 2012 R Geethalakshmi, DVL Sarada Department of Biotechnology, School of Bioengineering, Sri Ramaswamy Memorial University, Kattankulathur, Tamil Nadu, India Background: There is an increasing commercial demand for nanoparticles due to their wide applicability in various markets, including medicine, catalysis, electronics, chemistry, and energy. In this report, a simple and ecofriendly chemical reaction for the synthesis of gold and silver nanoparticles from Trianthema decandra (Aizoaceae) has been developed. Methods and results: On treatment of aqueous solutions containing chloroauric acid or silver nitrate with root extract of T. decandra, stable gold or silver nanoparticles were rapidly formed. The kinetics of reduction of gold and silver ions during the reaction was analyzed by ultraviolet-visible spectroscopy. Field emission-scanning electron microscopy showed formation of gold nanoparticles in various shapes, including spherical, cubical, triangular, and hexagonal, while silver nanoparticles were spherical. The size of the gold nanoparticles was 33–65 nm and that of the silver nanoparticles was 36–74 nm. Energy dispersive x-ray and Fourier transform infrared spectroscopy confirmed the presence of metallic gold and metallic silver in the respective nanoparticles. The antimicrobial properties of the synthesized nanoparticles were analyzed using the Kirby-Bauer method. The results show varied susceptibility of microorganisms to the gold and silver nanoparticles. Conclusion: It is believed that phytochemicals present in T. decandra extract reduce the silver and gold ions into metallic nanoparticles. This strategy reduces the cost of production and the environmental impact. The silver and gold nanoparticles formed showed strong activity against all microorganisms tested.
SYNTHESIS AND CHARACTERIZATION OF GOLD NANOPARTICLES BY JUSTICIA GENDARUSSA BURM F. LEAF EXTRACT  [PDF]
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 .
Synthesis of Gold Nanoparticles by Blue-Green Algae Spirulina Platensis  [cached]
Kalabegishvili T.,Faanhof A.,Kirkesali E.,Frontasyeva M.V.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2012,
Abstract: The synthesis of gold nanoparticles by one of the many popular microorganisms – blue-green algae Spirulina platensis was studied. The complex of optical and analytical methods was applied for investigation of experimental samples after exposure to chloroaurate (HAuCl4) solution at different doses and for different time intervals. To characterize formed gold nanoparticles UV-vis Spectrometry, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy-dispersive analysis of X-rays (EDAX) were used. It was shown that after 1.5–2 days of exposure the extracellular formation of nanoparticles of spherical form and the distribution peak within the interval of 20-30 nm took place. To determine gold concentrations in the Spirulina platensis biomass neutron activation analysis (NAA) was applied.
Ecofriendly Synthesis of Anisotropic Gold Nanoparticles: A Potential Candidate of SERS Studies  [PDF]
Ujjwala Gaware,Vaishali Kamble,Balaprasad Ankamwar
International Journal of Electrochemistry , 2012, DOI: 10.1155/2012/276246
Abstract: Ecofriendly synthesis of nanoparticles has been inspiring to nanotechnologists especially for biomedical applications. Moreover, anisotropic particle synthesis is an attractive option due to decreased symmetry of such particles often leads to new and unusual chemical and physical behaviour. This paper reports a single-step room-temperature synthesis of gold nanotriangles using a cheap bioresource of reducing and stabilizing agent Piper betle leaf extract. On treating aqueous chloroauric acid solution with Piper betle leaf extract, after 12 hr, complete reduction of the chloroaurate ions was observed leading to the formation of flat and single crystalline gold nanotriangles. These gold nanotriangles can be exploited in photonics, optical coating, optoelectronics, magnetism, catalysis, chemical sensing, and so forth, and are a potential candidate of SERS studies. 1. Introduction The synthesis of metal and semiconductor nanoparticles has innumerable opportunities of research due to their present and future applications in biosensing [1], chemical sensing [2], recording media [3], optoelectronics [4], and catalysis [5]. Masatake has reported [6] gold as a novel catalyst in the 21st century: it’s preparation, working mechanism, and application as the catalyst in CO oxidation. The majority of earlier research has focused on isotropic, that is, spherical particles. However, anisotropic particles are particularly interesting because the decreased symmetry of such particles often leads to new and unusual chemical and physical properties [7]. In this context, ecofriendly biosynthesis protocols are better roadmap to avoid adverse effects of nanomaterials especially in medical applications. Moreover, use of plant extracts as a reducing and capping agent for the synthesis of nanoparticles could be advantageous over other environmentally benign biological processes by eliminating the elaborate process of maintaining cell cultures. It can also be suitably scaled up for the large-scale synthesis of nanoparticles. The biosynthesis of platinum nanoparticles using Diospyros kaki leaf extract [8], silver nanoparticles using leaf extracts [9], silver and gold nanoparticles using phyllanthin [10], Clove extract [11], and within live Alfalfa plants in solid media [12] has been demonstrated. In recent studies, we have reported on the synthesis of gold nanoparticles by the reduction of aqueous ions using Cymbopogon flexuosus [13], Tamarindus indica [2], Emblica officinalis [14], Terminalia catappa [15], Murraya koenigii and Citrus limonum leaf extracts [16]. In the case of
Fungus-mediated biological synthesis of gold nanoparticles: potential in detection of liver cancer  [cached]
Chauhan A,Zubair S,Tufail S,Sherwani A
International Journal of Nanomedicine , 2011,
Abstract: Arun Chauhan1, Swaleha Zubair2, Saba Tufail1, Asif Sherwani1, Mohammad Sajid1, Suri C Raman3, Amir Azam4, Mohammad Owais1 1Interdisciplinary Biotechnology Unit, 2Women's College, Aligarh Muslim University, Aligarh, 3Institute of Microbial Technology, Chandigarh, 4Centre of Excellence in Material Sciences, Department of Applied Physics, Aligarh Muslim University, Aligarh, India Background: Nanomaterials are considered to be the pre-eminent component of the rapidly advancing field of nanotechnology. However, developments in the biologically inspired synthesis of nanoparticles are still in their infancy and consequently attracting the attention of material scientists throughout the world. Keeping in mind the fact that microorganism-assisted synthesis of nanoparticles is a safe and economically viable prospect, in the current study we report Candida albicans-mediated biological synthesis of gold nanoparticles. Methods and results: Transmission electron microscopy, atomic force microscopy, and various spectrophotometric analyses were performed to characterize the gold nanoparticles. The morphology of the synthesized gold particles depended on the abundance of C. albicans cytosolic extract. Transmission electron microscopy, nanophox particle analysis, and atomic force microscopy revealed the size of spherical gold nanoparticles to be in the range of 20–40 nm and nonspherical gold particles were found to be 60–80 nm. We also evaluated the potential of biogenic gold nanoparticles to probe liver cancer cells by conjugating them with liver cancer cell surface-specific antibodies. The antibody-conjugated gold particles were found to bind specifically to the surface antigens of the cancer cells. Conclusion: The antibody-conjugated gold particles synthesized in this study could successfully differentiate normal cell populations from cancerous cells. Keywords: gold nanoparticles, Candida albicans, biomimetic synthesis, cancer cell diagnosis, antiliver cell antibody
The Synthesis of Gold Nanoparticles Using Amaranthus spinosus Leaf Extract and Study of Their Optical Properties  [PDF]
Ratul Kumar Das, Nayanmoni Gogoi, Punuri Jayasekhar Babu, Pragya Sharma, Chandan Mahanta, Utpal Bora
Advances in Materials Physics and Chemistry (AMPC) , 2012, DOI: 10.4236/ampc.2012.24040
Abstract:

We report here the application of a medicinally important plant Amaranthus spinosus for the synthesis of gold nanoparticles (AuNPs). Different concentrations of ethanolic leaf extract of the plant were reacted with aqueous solution of HAuCl4·4H2O under mild reaction conditions. Synthesis of AuNPs was confirmed from the UV-Vis study of surface plasmon resonance property of the colloidal solution. Transmission electron microscopy (TEM) revealed particles as spherical and triangular in shape. X-ray diffraction (XRD) confirmed the crystalline nature of AuNPs with average size of 10.74 nm as determined by Debye-Scherrer’s Equation. Fourier transform infra-red (FT-IR) analysis of leaf extract and lyophilized AuNPs showed the presence of various functional groups present in diverse phytochemicals. Energy dispersive X-ray (EDX) of purified AuNPs confirmed the formation of AuNPs and surface adsorption of biomolecules. We further investigated the toxicity of the synthesized AuNPs and found non toxic to the cancer cell lines and could be used for biomedical applications.

Fungus-mediated biological synthesis of gold nanoparticles: potential in detection of liver cancer
Chauhan A, Zubair S, Tufail S, Sherwani A, Sajid M, Raman SC, Azam A, Owais M
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S23195
Abstract: ngus-mediated biological synthesis of gold nanoparticles: potential in detection of liver cancer Original Research (36171) Total Article Views Authors: Chauhan A, Zubair S, Tufail S, Sherwani A, Sajid M, Raman SC, Azam A, Owais M Published Date October 2011 Volume 2011:6 Pages 2305 - 2319 DOI: http://dx.doi.org/10.2147/IJN.S23195 Arun Chauhan1, Swaleha Zubair2, Saba Tufail1, Asif Sherwani1, Mohammad Sajid1, Suri C Raman3, Amir Azam4, Mohammad Owais1 1Interdisciplinary Biotechnology Unit, 2Women's College, Aligarh Muslim University, Aligarh, 3Institute of Microbial Technology, Chandigarh, 4Centre of Excellence in Material Sciences, Department of Applied Physics, Aligarh Muslim University, Aligarh, India Background: Nanomaterials are considered to be the pre-eminent component of the rapidly advancing field of nanotechnology. However, developments in the biologically inspired synthesis of nanoparticles are still in their infancy and consequently attracting the attention of material scientists throughout the world. Keeping in mind the fact that microorganism-assisted synthesis of nanoparticles is a safe and economically viable prospect, in the current study we report Candida albicans-mediated biological synthesis of gold nanoparticles. Methods and results: Transmission electron microscopy, atomic force microscopy, and various spectrophotometric analyses were performed to characterize the gold nanoparticles. The morphology of the synthesized gold particles depended on the abundance of C. albicans cytosolic extract. Transmission electron microscopy, nanophox particle analysis, and atomic force microscopy revealed the size of spherical gold nanoparticles to be in the range of 20–40 nm and nonspherical gold particles were found to be 60–80 nm. We also evaluated the potential of biogenic gold nanoparticles to probe liver cancer cells by conjugating them with liver cancer cell surface-specific antibodies. The antibody-conjugated gold particles were found to bind specifically to the surface antigens of the cancer cells. Conclusion: The antibody-conjugated gold particles synthesized in this study could successfully differentiate normal cell populations from cancerous cells.
GREEN SYNTHESIS OF GOLD NANOPARTICLES USING TOONA CILIATA METHANOL BARK EXTRACT AND THEIR CHARACTERISATION
Kaushik Rajan,Mann Avninder Singh,Sandhu Bharpur Singh,Parihar Vidya Bhushan Singh
International Research Journal of Pharmacy , 2012,
Abstract: In the present study, we identified and justified the use of MeOH extract from Toona ciliata bark as a reducing and capping agent for the ecofriendly synthesis of gold nanoparticles on the basis of modern analytical techniques. The reduction of 1.0 mM aqueous solution of aurochloric acid with 1 ml, 1% w/v aqueous solution of MeOH bark extract from Toona ciliata has resulted in the formation of stabilised Gold Nanoparticles (AuNPs). The synthesised gold particles showed a surface plasmon band around 550 nm when analysed via UV-Visible Spectroscopy, indicated the gold particles of nano dimensions (10-9 m). The Transmission Electron Microscopy (TEM) study of gold nano particles revealed the formation of spherical, poly dispersed nanoparticles of varying sizes ranging from 40-75 nm along with encapsulating cage. The time for the synthesis of gold nano particles was noted to be 30 minute. The preliminary phytochemical analysis of methanol extract form the bark confirmed the presence of alkaloids, glycosides, flavanoids, tannins and reducing sugars. The results of the present study clearly reveal the Toona ciliata methanolic bark extract as a new, novel and renewable, cost effective, reducing and capping agent for the application in the field of nanobiotechnology as well as pharmaceutical sciences. Further, the ecofriendly approach developed for AuNPs synthesis with Toona ciliata MeOH bark extract is the rapid and cost effective alternative to the traditional chemical methods of AuNPs synthesis.
Origin of optical second-harmonic generation in spherical gold nanoparticles: Local surface and nonlocal bulk contributions  [PDF]
Guillaume Bachelier,Jérémy Butet,Isabelle Russier-Antoine,Christian Jonin,Emmanuel Benichou,Pierre-Fran?ois Brevet
Physics , 2011, DOI: 10.1103/PhysRevB.82.235403
Abstract: The second-harmonic generation of 150 nm spherical gold nanoparticles is investigated both experimentally and theoretically. We demonstrate that the interference effects between dipolar and octupolar plasmons can be used as a fingerprint to discriminate the local surface and non-local bulk contributions to the second-harmonic generation. By fitting the experimental data with the electric fields computed with finite-element method (FEM) simulations, the Rudnick and Stern parameters weighting the relative nonlinear sources efficiencies are evaluated and the validity of the hydrodynamic model and the local density approximation approaches are discussed.
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