scholarly journals Modeling the Optical Responses of Noble Metal Nanoparticles Subjected to Physicochemical Transformations in Physiological Environments: Aggregation, Dissolution and Oxidation

2017 ◽  
Vol 231 (1) ◽  
Author(s):  
Jordi Piella ◽  
Neus G. Bastús ◽  
Víctor Puntes

AbstractHerein, we study how optical properties of colloidal dispersions of noble metal nanoparticles (Au and Ag) are affected by processes such as aggregation and oxidative dissolution. The optical contributions of these processes to the extinction spectra in the UV-vis region are often overlapped, making difficult its interpretation. In this regard, modeling the UV-vis spectra (in particular absorbance curve, peaks position, intensity and full width at half maximum -FWHM) of each process separately offers a powerful tool to identify the transformation of NPs under relevant and complex scenarios, such as in biological media. The proper identification of these transformations is crucial to understand the biological effects of the NPs.

2018 ◽  
Vol 9 ◽  
pp. 2763-2774 ◽  
Author(s):  
Alexander Rostek ◽  
Marina Breisch ◽  
Kevin Pappert ◽  
Kateryna Loza ◽  
Marc Heggen ◽  
...  

For a comparative cytotoxicity study, nanoparticles of the noble metals Rh, Pd, Ag, Pt, and Au (spherical, average diameter 4 to 8 nm) were prepared by reduction in water and colloidally stabilized with poly(N-vinyl pyrrolidone) (PVP). Thus, their shape, size, and surface functionalization were all the same. Size and morphology of the nanoparticles were determined by dynamic light scattering (DLS), analytical disc centrifugation (differential centrifugal sedimentation, DCS), and high-resolution transmission electron microscopy (HRTEM). Cell-biological experiments were performed to determine the effect of particle exposure on the viability of human mesenchymal stem cells (hMSCs). Except for silver, no adverse effect of any of the metal nanoparticles was observed for concentrations up to 50 ppm (50 mg L−1) incubated for 24 h, indicating that noble metal nanoparticles (rhodium, palladium, platinum, gold) that do not release ions are not cytotoxic under these conditions.


2021 ◽  
Vol 129 (12) ◽  
pp. 125302
Author(s):  
Wajeeha Saeed ◽  
Zeeshan Abbasi ◽  
Shumaila Majeed ◽  
Sohail Anjum Shahzad ◽  
Abdul Faheem Khan ◽  
...  

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 107 ◽  
Author(s):  
Ming Qin ◽  
Qing Chang ◽  
Yinkai Yu ◽  
Hongjing Wu

By the deposition of noble metal nanoparticles on a metal oxide substrate with a specific micro-/nanostructure, namely, yolk-shell structure, a remarkable improvement in photocatalytic performance can be achieved by the composites. Nevertheless, noble metal nanoparticles only distribute on the surface shell of metal oxide substrates when the conventional wet-chemistry reduction approach is employed. Herein, we proposed a novel acoustic levitation synthesis of Pt nanoparticles deposited on yolk-shell La2O3. The composites not only displayed well-defined, homogeneous distribution of Pt NPs on the exterior shell of La2O3 and the interior La2O3 core, but an enhanced chemical interaction between Pt and La2O3. The unique structure not only can display improved photocatalytic degradation rate toward methyl orange, but also may show great potential in fields of hydrogen generation, environmental protection, etc. The novel acoustic levitation synthesis can supplement the methodology of synthesizing well dispersed noble metal oxides over the whole yolk-shell structure through noble metal NPs deposition method.


2006 ◽  
Vol 86 (4) ◽  
pp. 477-480 ◽  
Author(s):  
C.E. Allmond ◽  
A.T. Sellinger ◽  
K. Gogick ◽  
J.M. Fitz-Gerald

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