scholarly journals Formation of Superlattices of Gold Nanoparticles Using Ostwald Ripening in Emulsions: Transition from fcc to bcc Structure

2016 ◽  
Vol 120 (25) ◽  
pp. 5759-5766 ◽  
Author(s):  
Julien Schmitt ◽  
Stéphanie Hajiw ◽  
Amélie Lecchi ◽  
Jéril Degrouard ◽  
Anniina Salonen ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ostwald Ripening ◽  
Bcc Structure

Synthesis of large gold nanoparticles with deformation twinnings by one-step seeded growth with Cu(ii)-mediated Ostwald ripening for determining nitrile and isonitrile groups

Nanoscale ◽  
2020 ◽  
Vol 12 (32) ◽  
pp. 16934-16943
Author(s):  
Chenshuo Wu ◽  
Hongpeng He ◽  
Yahui Song ◽  
Cuixia Bi ◽  
Lixiang Xing ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ostwald Ripening ◽  
Seeded Growth ◽  
Growth Method ◽  
One Step

Gold nanoparticles with deformation twinnings prepared by a Cu2+-assisted one-step seeded growth method can distinguish nitrile and isonitrile groups by SERS.

Controlled Growth of Gold Nanoparticles on Silica Nanowires

2005 ◽  
Vol 20 (11) ◽  
pp. 3021-3027 ◽  
Author(s):  
Aaron D. LaLonde ◽  
M. Grant Norton ◽  
Daqing Zhang ◽  
Devananda Gangadean ◽  
Abdullah Alkhateeb ◽  
...  
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Substrate Temperature ◽  
Size Distribution ◽  
Surface Diffusion ◽  
Ostwald Ripening ◽  
Size Control ◽  
Chemical Vapor ◽  
Chamber Pressure ◽  
Transmission Electron

Production of gold nanoparticles with the specific goal of particle size control has been investigated by systematic variation of chamber pressure and substrate temperature. Gold nanoparticles have been synthesized on SiO2 nanowires by plasma-enhanced chemical vapor deposition. Determination of particle size and particle size distribution was done using transmission electron microscopy. Average nanoparticle diameters were between 4 and 12 nm, with particle size increasing as substrate temperature increased from 573 to 873 K. A bimodal size distribution was observed at temperatures ≥723 K indicating Ostwald ripening dominated by surface diffusion. The activation energy for surface diffusion of gold on SiO2 was determined to be 10.4 kJ/mol. Particle sizes were found to go through a maximum with increases in chamber pressure. Competition between diffusion within the vapor and dissociation of the precursor caused the pressure effect.

scholarly journals Encapsidation of Different Plasmonic Gold Nanoparticles by the CCMV CP

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2628
Author(s):  
Ana L. Durán-Meza ◽  
Martha I. Escamilla-Ruiz ◽  
Xochitl F. Segovia-González ◽  
Maria V. Villagrana-Escareño ◽  
J. Roger Vega-Acosta ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Charge ◽  
Gold Nanorods ◽  
Self Assembly ◽  
Ostwald Ripening ◽  
Gold Nanoshells ◽  
Medical Applications ◽  
Cowpea Chlorotic Mottle Virus ◽  
Chlorotic Mottle Virus ◽  
Chlorotic Mottle

Different types of gold nanoparticles have been synthesized that show great potential in medical applications such as medical imaging, bio-analytical sensing and photothermal cancer therapy. However, their stability, polydispersity and biocompatibility are major issues of concern. For example, the synthesis of gold nanorods, obtained through the elongated micelle process, produce them with a high positive surface charge that is cytotoxic, while gold nanoshells are unstable and break down in a few weeks due to the Ostwald ripening process. In this work, we report the self-assembly of the capsid protein (CP) of cowpea chlorotic mottle virus (CCMV) around spherical gold nanoparticles, gold nanorods and gold nanoshells to form virus-like particles (VLPs). All gold nanoparticles were synthesized or treated to give them a negative surface charge, so they can interact with the positive N-terminus of the CP leading to the formation of the VLPs. To induce the protein self-assembly around the negative gold nanoparticles, we use different pH and ionic strength conditions determined from a CP phase diagram. The encapsidation with the viral CP will provide the nanoparticles better biocompatibility, stability, monodispersity and a new biological substrate on which can be introduced ligands toward specific cells, broadening the possibilities for medical applications.

scholarly journals Reaction Parameters for Controlled Sonosynthesis of Gold Nanoparticles

2017 ◽  
Vol 59 (2) ◽  
Author(s):  
Lourdes I. Cabrera-Lara
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Reaction Temperature ◽  
Ostwald Ripening ◽  
Nanoparticle Synthesis ◽  
Particle Morphology ◽  
Reducing Agent ◽  
Reaction Parameters ◽  
Sodium Tartrate ◽  
Sonochemical Reaction

The synthesis of gold nanoparticles by sonochemical technique has been previously performed with excellent results. The synthesis has been carried out in the presence of citric acid, a strong reducing agent, which allows the nucleation and growth of gold nanoparticles, at the same time that controls particle size. In this work, we report the use of sodium tartrate as a mild reducing agent that allows a better understanding of the effect of the reaction parameters during gold nanoparticle synthesis. A conventional sonication bath (37 kHz) was used for the sonochemical synthesis. This work focuses on the reaction temperature effect and the effect of sodium tartrate concentration. It was confirmed that particle size, and particle morphology is dependent of these two reaction parameters. Equally, colloidal stabilization was related to reaction temperature and sodium tartrate concentration. It was also determined that Ostwald ripening takes place during sonochemical reaction under our conditions, allowing us to understand the mechanism that takes place during synthesis. Gold nanoparticles with main particle size of 17 nm were achieved by this method.

scholarly journals Using Size-Exclusion Chromatography to Monitor Variations in the Sizes of Microwave-Irradiated Gold Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Fu-Ken Liu
Keyword(s):  
Gold Nanoparticles ◽  
Size Exclusion Chromatography ◽  
Ostwald Ripening ◽  
Sodium Dodecyl ◽  
Irradiation Temperature ◽  
Operating Conditions ◽  
Size Exclusion ◽  
Au Nps ◽  
Exclusion Chromatography ◽  
Mw Irradiation

Size-exclusion chromatography (SEC) was used to evaluate gold nanoparticles (Au NPs) for variations in their sizes after microwave (MW) irradiation, with the eluted NPs monitored through diode array detection to reveal their surface plasmon absorptions. The sizes of citrate-capped Au NPs decreased upon increasing the MW irradiation temperature, consistent with digestive ripening of these NPs under the operating conditions. In contrast, Au NPs capped with sodium dodecyl sulfate increased in size upon increasing the MW irradiation temperature, consistent with Ostwald ripening. When the Au NPs were capped with 3A-amino-3A-deoxy-(2AS,3AS)--cyclodextrin (H2N--CD), however, their dimensions were barely affected by the MW irradiation temperature, confirming that H2N--CD is a good stabilizer against MW irradiation. Therefore, SEC—with its short analysis times, low operating costs, automated operation, and in situ analysis—has great potential for use in the rapid monitoring of NPs subjected to treatment under various MW irradiation conditions.

scholarly journals Transport and coarsening of gold nanoparticles in an orogenic deposit by dissolution–reprecipitation and Ostwald ripening

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
E. C. G. Hastie ◽  
M. Schindler ◽  
D. J. Kontak ◽  
B. Lafrance
Keyword(s):  
Gold Nanoparticles ◽  
Focused Ion Beam ◽  
Ostwald Ripening ◽  
Ion Beam ◽  
Massive Sulfide ◽  
Gold Deposits ◽  
Oriented Attachment ◽  
High Grade ◽  
Transmission Electron ◽  
Primary Fluid

AbstractThe role of nanoparticle gold in the formation of gold deposits has long been debated. Evidence in support of this process is generally limited to epithermal-, Carlin- and seafloor massive-sulfide-type deposits where gold nanoparticles are associated with primary fluid related processes. At the Kenty orogenic deposit in Ontario, Canada, gold has been remobilized from early pyrite through secondary coupled dissolution-reprecipitation processes to form high-grade gold external to pyrite. Here we report gold nanoparticles and related textures that help document this gold coarsening process. A combination of focused ion beam technology and transmission electron microscopy provides a rare glimpse of gold coarsening frozen in time, which includes nanoparticles trapped in iron oxides and rutile and non-oriented attachment of gold nanoparticles to bulk gold suggesting coarsening via Ostwald ripening. The processes documented are applicable to orogenic deposits formed through Earth’s history, and may explain the formation of ultra high-grade ore zones.

scholarly journals Encapsidation of Different Plasmonic Gold Nanoparticles by the CCMV Capsid Protein

2018 ◽  
Author(s):  
Ana Luisa Duran-Meza ◽  
Martha Itzel Escamilla-Ruiz ◽  
Xochitl Fabiola Segovia-Gonzalez ◽  
Maria Veronica Villagrana-Escareño ◽  
J. Roger Vega-Acosta ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Surface Charge ◽  
Capsid Protein ◽  
Gold Nanorods ◽  
Self Assembly ◽  
Ostwald Ripening ◽  
Gold Nanoshells ◽  
Cowpea Chlorotic Mottle Virus ◽  
Chlorotic Mottle Virus ◽  
Chlorotic Mottle

Different types of gold nanoparticles have been synthesized that great potential in medical applications such as medical imaging, bio-analytical sensing and photothermal therapy. However, their stability, polydispersity and biocompatibility are major issues of concern. For example, the synthesis of gold nanorods, obtained through the elongated micelle process, produce them with a high positive surface charge that is cytotoxic. While gold nanoshells are unstable and within a few weeks they decompose due to Ostwald ripening. In this work, we report the self-assembly of the capsid protein of cowpea chlorotic mottle virus (CCMV) around spherical gold nanoparticles, gold nanorods and gold nanoshells to form virus-like particles (VLPs). All gold nanoparticles were synthesized or treated to give them a negative surface charge, so they can interact with the positive N-terminus of the capsid protein leading to the formation of the VLPs. To induce the protein self-assembly around the negative gold nanoparticles, we use different pH and ionic strength conditions that were determined from the capsid protein phase diagram. The encapsidation with the viral capsid protein confers them better biocompatibility, stability, monodispersity and a new biological substrate on which one can introduce specific ligands towards particular cells, broadening the possibilities of medical application.

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