Fullerene-Gold Core-Shell Structures and Their Self-Assemblies

2017 ◽  
Vol 16 (02) ◽  
pp. 1650029
Author(s):  
R. Sepahvand ◽  
S. Alihosseini ◽  
M. Adeli ◽  
P. Sasanpour
Keyword(s):  
Citric Acid ◽  
Self Assembly ◽  
Size Structure ◽  
Shell Structures ◽  
Core Shell ◽  
Hybrid Nanomaterial ◽  
Gold Core ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Gold Nps

Hybrid nanomaterials consisting of functionalized fullerene and gold nanoparticle (NP) have been synthesized. Fullerene was functionalized by citric acid and used as reducing and capping agent for preparation of gold NPs. Functionalization of fullerene by use of citric acid was performed by enzymatic and thermal approaches. The core-shell structures containing gold NPs as core and fullerene as shell (gold/fullerene) were prepared. It was found that method and density of functionalization of fullerene effect final structure and therefore their physicochemical property of hybrid nanomaterial dramatically. Ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), atomic force microscopy (AFM), transmission electron microscopy (TEM) were used to analyze the structure of the synthesized hybrid nanomaterial and also study their self-assembly and physicochemical properties. Effect of the size, structure and morphology (e.g., agglomeration) of the synthesized hybrid nanomaterial on their UV-Vis absorption behavior has been also verified by theoretical modeling.

Formation of bismuth iron oxide based core–shell structures and their dielectric, ferroelectric and magnetic properties

2019 ◽  
Vol 7 (5) ◽  
pp. 1280-1291 ◽  
Author(s):  
Alaka Panda ◽  
R. Govindaraj ◽  
R. Mythili ◽  
G. Amarendra
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Iron Oxide ◽  
Shell Structures ◽  
Core Shell ◽  
Bismuth Iron Oxide ◽  
The Core ◽  
Shell Nanostructures ◽  
Transmission Electron

Bismuth and iron oxides subjected to ball milling followed by controlled annealing treatments showed the formation of core–shell nanostructures with Bi2Fe4O9 as the core and a shell of BiFeO3 and Bi25FeO40 phases as deduced based on the analysis of transmission electron microscopy results.

scholarly journals Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3983
Author(s):  
Elżbieta Szczepańska ◽  
Beata Grobelna ◽  
Jacek Ryl ◽  
Amanda Kulpa ◽  
Tadeusz Ossowski ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Core Shell ◽  
Amino Groups ◽  
The Core ◽  
Transmission Electron ◽  
Model Sample ◽  
Vis Spectroscopy ◽  
Fmoc Group ◽  
Synthesis Procedure

In this paper, we described the synthesis procedure of TiO2@SiO2 core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc–glycine (Fmoc–Gly–OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) to confirm the modification effectiveness. The ultraviolet-visible spectroscopy (UV-vis) measurement was adopted for the quantitative determination of amino groups present on the TiO2@SiO2 core-shell surface by determination of Fmoc substitution. The nanomaterials were functionalized by Fmoc–Gly–OH and then the fluorenylmethyloxycarbonyl (Fmoc) group was cleaved using 20% (v/v) solution of piperidine in DMF. This reaction led to the formation of a dibenzofulvene–piperidine adduct enabling the estimation of free Fmoc groups by measurement the maximum absorption at 289 and 301 nm using UV-vis spectroscopy. The calculations of Fmoc loading on core-shell materials was performed using different molar absorption coefficient: 5800 and 6089 dm3 × mol−1 × cm−1 for λ = 289 nm and both 7800 and 8021 dm3 × mol−1 × cm−1 for λ = 301 nm. The obtained results indicate that amount of Fmoc groups present on TiO2@SiO2–(CH2)3–NH2 was calculated at 6 to 9 µmol/g. Furthermore, all measurements were compared with Fmoc–Gly–OH used as the model sample.

Carbon–gold core–shell structures: formation of shells consisting of gold nanoparticles

2012 ◽  
Vol 48 (33) ◽  
pp. 3972 ◽  
Author(s):  
Jerzy Choma ◽  
Dominik Jamioła ◽  
Katarzyna Augustynek ◽  
Michal Marszewski ◽  
Mietek Jaroniec
Keyword(s):  
Gold Nanoparticles ◽  
Shell Structures ◽  
Core Shell ◽  
Gold Core

Self-Assembly of Gold Nanoparticles on Gold Core-Induced Polypyrrole Nanohybrids for Electrochemical Sensor of Dopamine

NANO ◽  
2015 ◽  
Vol 10 (08) ◽  
pp. 1550115 ◽  
Author(s):  
Junwei Ding ◽  
Kai Zhang ◽  
Wei Xu ◽  
Zhiqiang Su
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Self Assembly ◽  
Chemical Oxidation ◽  
X Ray Diffraction ◽  
Detection Range ◽  
In Situ Chemical Oxidation ◽  
Gold Core ◽  
Transmission Electron ◽  
Chemical Oxidation Polymerization

Gold core-induced polypyrrole nanohybrids (Au–PPyNHs) were successfully synthesized via in situ chemical oxidation polymerization of pyrrole molecules, and their structure was directly confirmed and characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Furthermore, gold nanoparticles (AuNPs) were assembled onto the as-prepared Au–PPyNHs by electrostatic interaction to fabricate the nanohybrids of Au–PPyNH–Au. The created Au–PPyNH–Au nanohybrids was immobilized onto glassy carbon electrode and applied to construct dopamine (DA) sensor. We found that the fabricated sensor with Au–PPyNH–Au nanohybrids is highly specific probe for sensing DA. The Au–PPyNH–Au based DA sensor has a linear detection range from 1[Formula: see text][Formula: see text]M to 0.321 mM and a detection limit of 0.32[Formula: see text][Formula: see text]M.

Synthesis of rod-like silica–gold core-shell structures

2012 ◽  
Vol 393 ◽  
pp. 37-41 ◽  
Author(s):  
Jerzy Choma ◽  
Dominik Jamioła ◽  
Piotr Nyga ◽  
Mietek Jaroniec
Keyword(s):  
Shell Structures ◽  
Core Shell ◽  
Gold Core

scholarly journals Characterization and Cytotoxicity Comparison of Silver- and Silica-Based Nanostructures

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4987
Author(s):  
Elżbieta Adamska ◽  
Karolina Niska ◽  
Anna Wcisło ◽  
Beata Grobelna
Keyword(s):  
Strong Relationship ◽  
Core Shell ◽  
The Novel ◽  
Skin Cells ◽  
Angle Measurements ◽  
Novel Approach ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Adhesion Efficiency

Core-shell structures are the most common type of composite material nanostructures due to their multifunctional properties. Silver nanoparticles show broad antimicrobial activity, but the safety of their utilization still remains an issue to tackle. In many applications, the silver core is coated with inorganic shell to reduce the metal toxicity. This article presents the synthesis of various materials based on silver and silica nanoparticles, including SiO2@Ag, Ag@SiO2, and sandwich nanostructures—Ag@SiO2@Ag—and the morphology of these nanomaterials based on transmission electron microscopy (TEM), UV-Vis spectroscopy, and FT-IR spectroscopy. Moreover, we conducted the angle measurements due to the strong relationship between the level of surface wettability and cell adhesion efficiency. The main aim of the study was to determine the cytotoxicity of the obtained materials against two types of human skin cells—keratinocytes (HaCaT) and fibroblasts (HDF). We found that among all the obtained structures, SiO2@Ag and Ag@SiO2 showed the lowest cell toxicity and very high half-maximal inhibitory concentration. Moreover, the measurements of the contact angle showed that Ag@SiO2 nanostructures were different from other materials due to their superhydrophilic nature. The novel approach presented here shows the promise of implementing core-shell type nanomaterials in skin-applied cosmetic or medical products.

scholarly journals Core-Shell Au@Ag Nanoparticles Synthesized with Polyphenols as Antimicrobial Agents

2021 ◽  
Author(s):  
Jesús Mauro Adolfo Villalobos-Noriega ◽  
Ericka Rodríguez Leon ◽  
César Rodríguez-Beas ◽  
Eduardo Larios-Rodríguez ◽  
Maribel Plascencia-Jatomea ◽  
...  
Keyword(s):  
Growth Kinetic ◽  
Antimicrobial Agents ◽  
Bimetallic Nanoparticles ◽  
Kinetic Curve ◽  
Core Shell ◽  
Root Extract ◽  
X Ray ◽  
Transmission Electron ◽  
Gold Silver ◽  
Vis Spectroscopy

Abstract In this work, we used a sequential method of synthesis for gold-silver bimetallic nanoparticles with core@shell structure (Au@AgNPs). Rumex hymenosepalus root extract (Rh), which presents high content in catechins and stilbenes, was used as reductor agent in nanoparticles synthesis. Size distribution obtained by Transmission Electron Microscopy (TEM) give a diameter mean of 36 nm for Au@AgNPs, and 24 nm for gold nanoparticles (AuNPs). The geometrical shapes of NPs were principally quasi-spherical. The thickness of silver shell over AuNPs are around 6 nm and covered by active biomolecules onto surface. Microstructural characterization included high angle annular dark field images (HAADF) recorded with a scanning transmission electron microscope (STEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-Ray Diffraction (XRD), UV-Vis Spectroscopy, and Zeta Potential. Also, a growth kinetic curve analysis using the Gompertz model for Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative), and Candida albicans (yeast) were carried out for Au@AgNPs and monometallic AuNPs and AgNPs. Interestingly, Gompertz analysis indicates that Au@AgNPs present a higher effect on the growth kinetic of microorganisms than shown by monometallic nanoparticles.

Highly Luminescent Inverted ZnS/CdS Core/Shell Quantum Dots

2008 ◽  
Vol 8 (8) ◽  
pp. 3949-3954 ◽  
Author(s):  
Madhulika Sharma ◽  
D. Gupta ◽  
D. Kaushik ◽  
A. B. Sharma ◽  
R. K. Pandey
Keyword(s):  
Quantum Dots ◽  
Grazing Angle ◽  
Surface States ◽  
Shell Structures ◽  
Luminescence Spectroscopy ◽  
Core Shell ◽  
Additional Parameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Synthesis of highly luminescent and monochromatic inverted core–shell structures utilizing ZnS/CdS quantum dots (QDs) has been investigated. The core/shell quantum dots have been characterized using grazing angle X-ray diffraction (XRD), Transmission electron microscopy, Optical absorption and luminescence spectroscopy. The results suggested that passivation of surface states along with an increased localization of electron and hole in CdS shell layer, give rise to increased monochromaticity with higher quantum yield. The possibility of using the inverted core–shell structure as an additional parameter for tuning the color of luminescence has also been discussed.

Structural Characterization of Nanoparticles Obtained by a Polyol Synthesis in the Bimetallic System Pt-Pd

2012 ◽  
Vol 1372 ◽  
Author(s):  
A. F. García-Ruiz ◽  
J. J. Velázquez Salazar ◽  
R. Esparza ◽  
N. Castillo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Bimetallic Nanoparticles ◽  
Synthesis Method ◽  
Shell Structures ◽  
Polyol Synthesis ◽  
Core Shell ◽  
Thermal Methods ◽  
Transmission Electron ◽  
Bimetallic System

ABSTRACTA modified polyol synthesis has been utilized to study the different structures obtained in the bimetallic system of platinum (Pt) and palladium (Pd). Some results are shown in this work. Thermal methods under refluxing, carrying on the reaction up to 285 ºC, have been assayed to reduce metallic salts using ethylene glycol (EG) as reducer and polyvinylpyrrolidone (PVP) as protective reagent of the formed bimetallic nanoparticles. The special core-shell structure has been observed in these bimetallic nanoparticles, whose synthesis was assisted by Ag, showing polyhedral shapes. The average diameter size of the core has been estimated at 10 nm, and the diameter size of the shell in 13 nm, consequently the thickness of the shell is around 1.5 nm. Nanoparticles were structurally characterized with transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) equipped with detector to generate high angle annular dark field (HAADF) images. This kind of structures have been studied and utilized to increase successfully the catalytic properties of monometallic nanoparticles of Pt or Pd according to other works. Here, the synthesis procedure is described; as the main results, several images are presented showing the obtained bimetallic core-shell structures and their fast Fourier transform (FFT), and also the size and the elemental analysis of the nanoparticles are reported, concluding that this synthesis method is very efficient for preparing bimetallic core shell structures.

scholarly journals A facile method for the preparation of bifunctional Mn:ZnS/ZnS/Fe3O4 magnetic and fluorescent nanocrystals

2015 ◽  
Vol 6 ◽  
pp. 1743-1751 ◽  
Author(s):  
Houcine Labiadh ◽  
Tahar Ben Chaabane ◽  
Romain Sibille ◽  
Lavinia Balan ◽  
Raphaël Schneider
Keyword(s):  
Core Shell ◽  
Remnant Magnetization ◽  
Biological Applications ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Magnetite Layer ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Magnetic Shell

Bifunctional magnetic and fluorescent core/shell/shell Mn:ZnS/ZnS/Fe3O4 nanocrystals were synthesized in a basic aqueous solution using 3-mercaptopropionic acid (MPA) as a capping ligand. The structural and optical properties of the heterostructures were characterized by X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence (PL) spectroscopy. The PL spectra of Mn:ZnS/ZnS/Fe3O4 quantum dots (QDs) showed marked visible emission around 584 nm related to the 4T1 → 6A1 Mn2+ transition. The PL quantum yield (QY) and the remnant magnetization can be regulated by varying the thickness of the magnetic shell. The results showed that an increase in the thickness of the Fe3O4 magnetite layer around the Mn:ZnS/ZnS core reduced the PL QY but improved the magnetic properties of the composites. Nevertheless, a good compromise was achieved in order to maintain the dual modality of the nanocrystals, which may be promising candidates for various biological applications.

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