THE ABSORPTION PROPERTIES OF GOLD NANO CONJUGATED WITH PROTEINS

2020 ◽  
Vol 65 (10) ◽  
pp. 29-35
Author(s):  
Theu Luong Thi ◽  
Thi Le Anh ◽  
Huy Tran Quang ◽  
Hoc Nguyen Quang ◽  
Hoa Nguyen Minh
Keyword(s):  
Complex System ◽  
Absorption Spectrum ◽  
Metallic Nanoparticles ◽  
Biomedical Applications ◽  
Mie Theory ◽  
Core Shell ◽  
Absorption Properties ◽  
The Core ◽  
Good Agreement ◽  
Nanoparticle Complex

The absorption properties of protein-conjugated metallic nanoparticles are theoretically investigated based on the Mie theory and the core-shell model. Our numerical calculations show that this finding is in good agreement with previous experiments. We provide a better interpretation of the origin of optical peaks in the absorption spectrum of the nanoparticle complex system. Our results can be used in biomedical applications.

scholarly journals Optical Properties of Silver Nanowires Conjugated with Protein

2021 ◽  
Vol 31 (3) ◽  
Author(s):  
Do Thi Nga ◽  
Vu Van Huy ◽  
Chu Viet Ha
Keyword(s):  
Optical Properties ◽  
Absorption Spectrum ◽  
Shell Model ◽  
Silver Nanowires ◽  
Mie Theory ◽  
Optical Spectra ◽  
Numerical Calculations ◽  
Core Shell ◽  
The Core ◽  
Good Agreement

Optical properties of protein-conjugated metallic nanowires are theoretically investigated based on the Mie theory and the core-shell model. Our numerical calculations show that optical spectra of protein-conjugated nanowires can have more a maximum compared to these nanowires without biomolecules. This finding is in a good agreement with previous experiments. We provide better interpretation for the origin of optical peaks in absorption spectrum of nanowires. Our results can be used for designing biosensors and bio-detectors.

Microwave absorption properties of the core/shell-type iron and nickel nanoparticles

2008 ◽  
Vol 320 (6) ◽  
pp. 1106-1111 ◽  
Author(s):  
B. Lu ◽  
X.L. Dong ◽  
H. Huang ◽  
X.F. Zhang ◽  
X.G. Zhu ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Nickel Nanoparticles ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
The Core ◽  
Shell Type

An Easy Route to Synthesize Novel Fe3O4@Pt Core-shell Nanostructures with High Electrocatalytic Activity

2012 ◽  
Vol 15 (3) ◽  
pp. 171-179 ◽  
Author(s):  
Nora Mayté Sánchez-Padilla ◽  
Sagrario M. Montemayor ◽  
F.J. Rodríguez Varela
Keyword(s):  
Electrocatalytic Activity ◽  
Metallic Nanoparticles ◽  
Specific Activity ◽  
Synthesis Temperature ◽  
Reduction Reaction ◽  
Core Shell ◽  
Spinel Type ◽  
Electron Transfer Mechanism ◽  
The Core ◽  
Shell Nanostructures

In this work, the effect of changing the stirring method and temperature on the physicochemical properties of metallic nanoparticles and core-shell nanostructures is shown. Magnetic (MS), mechanical (UT) and ultrasonic (USS) stirring are the methods of synthesis. The effect that, temperatures between 0 and 50 °C, has on the structure and particle size of Fe3O4 nanoparticles is evaluated. The results indicate that Fe3O4 prepared by the three methods presents a spinel-type crystalline structure. An increase in the synthesis temperature leads to highly crystalline powders. Afterwards, Pt is deposited by the UT method on Fe3O4 to form Fe3O4@Pt core-shell nanostructures. It is important to mention that the time used for the synthesis of the nanoparticles and the core-shell nanostructures is only one minute. The presence of Fe3O4 and Pt is confirmed by XRD and XPS. The metallic Pt phase is confirmed because the binding energy of Pt 4f 7/2 is associated to platinum in the zero-valent state. We evaluated the electrochemical activity of the Fe3O4@Pt core-shell nanostructures for the oxygen reduction reaction (ORR). The novel materials show a high electrocatalytic activity and the Koutecky-Levich analysis indicates that the reaction follows a 4 electron transfer mechanism on the Fe3O4@Pt nanostructures prepared by the three stirring processes. Moreover, the mass specific activity of the core-shell materials is as high as that obtained from the Pt-alone catalysts, suggesting that the amount of Pt in these electrodes can be reduced without decreasing the performance.

Microstructure in Pressureless-Sintered Iron-Containing Hydroxyapatite/Titanium Composites

2010 ◽  
Vol 160-162 ◽  
pp. 1582-1587 ◽  
Author(s):  
Qing Chang ◽  
Hong Qiang Ru ◽  
Dao Lun Chen
Keyword(s):  
Low Temperature ◽  
Biomedical Applications ◽  
Core Shell ◽  
Pressureless Sintering ◽  
Shell Microstructure ◽  
Sintered Iron ◽  
The Core ◽  
Reinforcing Particles ◽  
New Type ◽  
Core Shell Structure

Pure hydroxyapatite (HA) is brittle and it cannot be directly used for the load-bearing biomedical applications. Aim of this paper was to present a new iron-containing hydroxyapatite/titanium composites synthesized via pressureless sintering at a relatively low temperature of 1000°C using nano-sized HA powders and Ti-33%Fe mixed powders. The microstructure and composition of the new type composites were evaluated. The results showed that the uniformly distributed reinforcing particles had a unique and favorable core/shell microstructure after sintering that consisted of outer titanium and inner iron. The mechanism for the formation of the core/shell structure was discussed. The addition of iron reduced the decomposition rate of HA and the interaction between HA and titanium.

Investigation of the electromagnetic absorption properties of Ni@TiO2 and Ni@SiO2 composite microspheres with core–shell structure

2015 ◽  
Vol 17 (4) ◽  
pp. 2531-2539 ◽  
Author(s):  
Biao Zhao ◽  
Gang Shao ◽  
Bingbing Fan ◽  
Wanyu Zhao ◽  
Rui Zhang
Keyword(s):  
Electromagnetic Wave ◽  
Reflection Loss ◽  
Core Shell ◽  
Absorption Properties ◽  
Electromagnetic Wave Absorption ◽  
The Core ◽  
Composite Microspheres ◽  
Electromagnetic Absorption ◽  
Core Shell Structure ◽  
Minimum Reflection Loss

The core–shell Ni–SiO2 composite exhibits the best electromagnetic wave absorption in the GHz range with a minimum reflection loss of −40.0 dB, which is superior to those of Ni–TiO2 and Ni microspheres.

Synthesis and Micro-Wave Absorption Properties of BiFeO3 Coated Fe Nanocapsules

2013 ◽  
Vol 712-715 ◽  
pp. 229-232 ◽  
Author(s):  
Gui Mei Shi ◽  
Da Wei Lu ◽  
Yan Zhang
Keyword(s):  
Reflection Loss ◽  
Photoelectron Spectrum ◽  
Core Shell ◽  
Absorber Thickness ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
X Ray ◽  
The Core ◽  
Core Shell Structure ◽  
Thickness Layer

BiFeO3coated ferromagnetic Fe nanocapsules is synthesized by arc-discharging method. Typical HRTEM images show that the nanocapsules form in a core-shell structure. X-ray photoelectron spectrum (XPS) and X-ray diffraction (XRD) reveal that the core is ferromagnetic Fe, while the shell is BiFeO3/Bi2Fe4O9.The reflection loss R of less than -10 dB was obtained for the whole frequency within the 2-18GHz range by choosing an appropriate layer thickness between 1.0mm and 7.0mm. An optimal reflection loss of -21.5 dB was reached at 10.6 GHz with an absorber thickness of 2.0mm. It is worth noticing that the BiFeO3coated Fe nanocapsules have two absorption peaks below -10 dB at each thickness layer ranging from 4.0nm to 7.0nm, which means the composites nanocapsules absorber simultaneously are able to absorb microwaves in different band of several GHz.

Facile preparation and enhanced microwave absorption properties of core–shell composite spheres composited of Ni cores and TiO2 shells

2015 ◽  
Vol 17 (14) ◽  
pp. 8802-8810 ◽  
Author(s):  
Biao Zhao ◽  
Gang Shao ◽  
Bingbing Fan ◽  
Wanyu Zhao ◽  
Yajun Xie ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Core Shell ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
The Core ◽  
Facile Preparation ◽  
Shell Composite

The microwave absorption properties of the core–shell Ni@rutile TiO2 composite are superior to those of the Ni@anatase TiO2 composite.

scholarly journals Combined extinction and absorption UV–vis spectroscopy reveals shape imperfections of metallic nanoparticles

2020 ◽  
Author(s):  
Johan Grand ◽  
Baptiste Auguié ◽  
Eric Le Ru
Keyword(s):  
Absorption Spectrum ◽  
Plasmon Resonance ◽  
Metallic Nanoparticles ◽  
Extinction Spectrum ◽  
Mie Theory ◽  
Integrating Sphere ◽  
Surface Integral ◽  
Modeling Tools ◽  
Vis Spectroscopy ◽  
Silver Nanospheres

Copyright © 2019 American Chemical Society. Metallic nanoparticle solutions are routinely characterized by measuring their extinction spectrum (with UV-vis spectroscopy). Theoretical predictions such as Mie theory for spheres can then be used to infer important properties, such as particle size and concentration. Here we highlight the benefits of measuring not only the extinction (the sum of absorption and scattering) but also the absorption spectrum (which excludes scattering) for routine characterization of metallic nanoparticles. We use an integrating sphere-based method to measure the combined extinction-absorption spectra of silver nanospheres and nanocubes. Using a suite of electromagnetic modeling tools (Mie theory, T-matrix, surface integral equation methods), we show that the absorption spectrum, in contrast to extinction, is particularly sensitive to shape imperfections such as roughness, faceting, or edge rounding. We study in detail the canonical case of silver nanospheres, where small discrepancies between experimental and calculated extinction spectra are still common and often overlooked. We show that this mismatch between theory and experiment becomes much more important when considering the absorption spectrum and can no longer be dismissed as experimental imperfections. We focus in particular on the quadrupolar localized plasmon resonance of silver nanospheres, which is predicted to be very prominent in the absorption spectrum but is not observed in our experiments. We consider and discuss a number of possible explanations to account for this discrepancy, including changes in the dielectric function of Ag, size polydispersity, and shape imperfections such as elongation, faceting, and roughness. We are able to pinpoint faceting and roughness as the likely causes for the observed discrepancy. A similar analysis is carried out on silver nanocubes to demonstrate the generality of this conclusion. We conclude that the absorption spectrum is in general much more sensitive to the fine details of a nanoparticle geometry, compared to the extinction spectrum. The ratio of extinction to absorption also provides a sensitive indicator of size for many types of nanoparticles, much more reliably than any observed plasmon resonance shifts. Overall, this work demonstrates that combined absorption-extinction measurements provide a much richer characterization tool for metallic nanoparticles.

scholarly journals Combined extinction and absorption UV–vis spectroscopy reveals shape imperfections of metallic nanoparticles

2020 ◽  
Author(s):  
Johan Grand ◽  
Baptiste Auguié ◽  
Eric Le Ru
Keyword(s):  
Absorption Spectrum ◽  
Plasmon Resonance ◽  
Metallic Nanoparticles ◽  
Extinction Spectrum ◽  
Mie Theory ◽  
Integrating Sphere ◽  
Surface Integral ◽  
Modeling Tools ◽  
Vis Spectroscopy ◽  
Silver Nanospheres

Copyright © 2019 American Chemical Society. Metallic nanoparticle solutions are routinely characterized by measuring their extinction spectrum (with UV-vis spectroscopy). Theoretical predictions such as Mie theory for spheres can then be used to infer important properties, such as particle size and concentration. Here we highlight the benefits of measuring not only the extinction (the sum of absorption and scattering) but also the absorption spectrum (which excludes scattering) for routine characterization of metallic nanoparticles. We use an integrating sphere-based method to measure the combined extinction-absorption spectra of silver nanospheres and nanocubes. Using a suite of electromagnetic modeling tools (Mie theory, T-matrix, surface integral equation methods), we show that the absorption spectrum, in contrast to extinction, is particularly sensitive to shape imperfections such as roughness, faceting, or edge rounding. We study in detail the canonical case of silver nanospheres, where small discrepancies between experimental and calculated extinction spectra are still common and often overlooked. We show that this mismatch between theory and experiment becomes much more important when considering the absorption spectrum and can no longer be dismissed as experimental imperfections. We focus in particular on the quadrupolar localized plasmon resonance of silver nanospheres, which is predicted to be very prominent in the absorption spectrum but is not observed in our experiments. We consider and discuss a number of possible explanations to account for this discrepancy, including changes in the dielectric function of Ag, size polydispersity, and shape imperfections such as elongation, faceting, and roughness. We are able to pinpoint faceting and roughness as the likely causes for the observed discrepancy. A similar analysis is carried out on silver nanocubes to demonstrate the generality of this conclusion. We conclude that the absorption spectrum is in general much more sensitive to the fine details of a nanoparticle geometry, compared to the extinction spectrum. The ratio of extinction to absorption also provides a sensitive indicator of size for many types of nanoparticles, much more reliably than any observed plasmon resonance shifts. Overall, this work demonstrates that combined absorption-extinction measurements provide a much richer characterization tool for metallic nanoparticles.

scholarly journals Combined extinction and absorption UV–vis spectroscopy reveals shape imperfections of metallic nanoparticles

2020 ◽  
Author(s):  
Johan Grand ◽  
Baptiste Auguié ◽  
Eric Le Ru
Keyword(s):  
Absorption Spectrum ◽  
Plasmon Resonance ◽  
Metallic Nanoparticles ◽  
Extinction Spectrum ◽  
Mie Theory ◽  
Integrating Sphere ◽  
Surface Integral ◽  
Modeling Tools ◽  
Vis Spectroscopy ◽  
Silver Nanospheres

Copyright © 2019 American Chemical Society. Metallic nanoparticle solutions are routinely characterized by measuring their extinction spectrum (with UV-vis spectroscopy). Theoretical predictions such as Mie theory for spheres can then be used to infer important properties, such as particle size and concentration. Here we highlight the benefits of measuring not only the extinction (the sum of absorption and scattering) but also the absorption spectrum (which excludes scattering) for routine characterization of metallic nanoparticles. We use an integrating sphere-based method to measure the combined extinction-absorption spectra of silver nanospheres and nanocubes. Using a suite of electromagnetic modeling tools (Mie theory, T-matrix, surface integral equation methods), we show that the absorption spectrum, in contrast to extinction, is particularly sensitive to shape imperfections such as roughness, faceting, or edge rounding. We study in detail the canonical case of silver nanospheres, where small discrepancies between experimental and calculated extinction spectra are still common and often overlooked. We show that this mismatch between theory and experiment becomes much more important when considering the absorption spectrum and can no longer be dismissed as experimental imperfections. We focus in particular on the quadrupolar localized plasmon resonance of silver nanospheres, which is predicted to be very prominent in the absorption spectrum but is not observed in our experiments. We consider and discuss a number of possible explanations to account for this discrepancy, including changes in the dielectric function of Ag, size polydispersity, and shape imperfections such as elongation, faceting, and roughness. We are able to pinpoint faceting and roughness as the likely causes for the observed discrepancy. A similar analysis is carried out on silver nanocubes to demonstrate the generality of this conclusion. We conclude that the absorption spectrum is in general much more sensitive to the fine details of a nanoparticle geometry, compared to the extinction spectrum. The ratio of extinction to absorption also provides a sensitive indicator of size for many types of nanoparticles, much more reliably than any observed plasmon resonance shifts. Overall, this work demonstrates that combined absorption-extinction measurements provide a much richer characterization tool for metallic nanoparticles.

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