scholarly journals Characterization of Magnetite–Silica Magnetic Fluids by Laser Scattering

2020 ◽  
Vol 11 (1) ◽  
pp. 183
Author(s):  
Elena N. Velichko ◽  
Elina K. Nepomnyashchaya ◽  
Kamil G. Gareev ◽  
Javier Martínez ◽  
Marco C. Maicas
Keyword(s):  
Magnetic Properties ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Aspect Ratio ◽  
Magnetic Fluids ◽  
High Energy ◽  
Sedimentation Stability ◽  
Laser Scattering ◽  
Diluted Magnetic ◽  
The Stability

The paper is concerned with structural, morphological and magnetic properties of magnetite-silica magnetic fluids. The granulometric composition of the magnetic fluids was investigated by scanning and transmission electron microscopy, the phase composition was studied by X-ray diffraction and reflection high-energy electron diffraction, and magnetic properties were studied by vibrating sample magnetometry. In order to reveal the particle size distribution, dynamic light scattering and a proposed modification of depolarized dynamic light scattering were employed. The shape and dimensions of magnetic nanoparticles and also their aggregates are described. While the aspect ratio for the aggregates was 0.5–0.99, individual nanoparticles had an average aspect ratio of 0.9 and were nearly spherical. The sedimentation stability of a diluted magnetic fluid was also investigated. When the fluids were diluted 200 times, the stability was partially lost, and the nanoparticles aggregated, thereby forming clusters, and precipitated.

scholarly journals Applicability and Limitations in the Characterization of Poly-Dispersed Engineered Nanomaterials in Cell Media by Dynamic Light Scattering (DLS)

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3833 ◽  
Author(s):  
Arianna Marucco ◽  
Elisabetta Aldieri ◽  
Riccardo Leinardi ◽  
Enrico Bergamaschi ◽  
Chiara Riganti ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Culture Media ◽  
Raw 264.7 ◽  
Pre Treatment ◽  
The Stability ◽  
Definition Of ◽  
Cellular Tests

The dispersion protocol used to administer nanomaterials (NMs) in in vitro cellular tests might affect their toxicity. For this reason, several dispersion procedures have been proposed to harmonize the toxicological methods, allowing for the comparison of the data that were obtained by different laboratories. At the same time, several techniques and methods are available to monitor the identity of the NMs in the cell media. However, while the characterization of suspensions of engineered NMs having narrow size distribution may be easily performed, the description of aggregated NMs forming polydispersions is still challenging. In the present study, sub-micrometric/nanometric TiO2, SiO2, and CeO2 were dispersed in cell media by using two different dispersion protocols, with and without albumin (0.5%) and with different sonication procedures. Dynamic Light Scattering (DLS) was used to characterize NMs in stock solutions and culture media. Pitfalls that affect DLS measurements were identified and, guidance on a critical analysis of the results provided. The NMs were then tested for their cytotoxicity (LDH leakage) toward murine macrophages (RAW 264.7) and PMA-activated human monocytes (THP-1). As markers of pro-inflammatory response, nitric oxide (NO) and cytokine IL-1β production were measured on RAW 264.7 and THP-1 cells, respectively. The pre-treatment with albumin added to a strong sonication treatment increases the stability and homogeneity of the suspensions of nanometric samples, but not of the submicrometric-samples. Nevertheless, while TiO2 and CeO2 were non-cytotoxic in any conditions, differences in cytotoxicity, NO, and IL-1β releases were found for the SiO2, depending upon the protocol. Overall, the results suggest that there is no one-fits-all method valid for all NMs, since each class of NMs respond differently. The definition of validated procedures and parameters for the selection of the most appropriate method of dispersion for each class of NM appears to be a more efficacious strategy for the harmonization of the dispersion protocols.

Dynamic light scattering studies of the stability and growth of silica particles

1993 ◽  
Vol 159 (1-2) ◽  
pp. 73-79 ◽  
Author(s):  
Rogelio Rodríguez ◽  
Rubén Arroyo ◽  
Pastora Salinas
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Silica Particles ◽  
The Stability

The Influence of Heating and Photosensitization on the Stability of Lutein- Loaded Lipid-Core Nanocapsules

2020 ◽  
Vol 16 (9) ◽  
pp. 1340-1345
Author(s):  
Aelson A.S. Brum ◽  
Médelin M. da Silva ◽  
Priscilla P. dos Santos ◽  
Allana V.S. Brasil ◽  
Karina Paese ◽  
...  
Keyword(s):  
Activation Energy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Zeta Potential ◽  
Singlet Oxygen ◽  
Food Industry ◽  
Entrapment Efficiency ◽  
Average Diameter ◽  
Lipid Core ◽  
The Stability

Background: Despite lutein is unstable in light, heat, and oxygen, it is a good quencher of singlet oxygen. The present study evaluated the stability of lutein (92% of purity) in Lipid-core Nanocapsules (Lutein-LNC) prepared through interfacial deposition of preformed polymer, during photosensitization (5-25°C) and heating (70-90°C). Methods: The Lutein-LNC was characterized and presented a polydispersity index of 0.11, an average diameter of 191 nm (dynamic light scattering), zeta potential of -9.14 mV and entrapment efficiency of 100%. Results and Discussion: During photosensitization and heating, Lutein-LNC exhibited activation Energy (Ea) of 24.67 kcal/mol and 9.96 kcal/mol, respectively, and these values of Lutein-LNC were higher than free lutein values, reported in other studies for both experiments. Conclusion: The results obtained in this study suggested that nanotechnology can improve the stability of lutein for future applications in the food industry.

Dispersion and Stability of Nanoalumina in Solution Prior to Exposure

2013 ◽  
Vol 850-851 ◽  
pp. 16-19
Author(s):  
Zai Yu ◽  
Shi Chuan Tang ◽  
Peng Zhao ◽  
Ru Gang Zhong ◽  
Bing Chang
Keyword(s):  
Particle Size ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Normal Saline ◽  
Sonication Time ◽  
Aggregation Size ◽  
The Stability ◽  
Phosphate Buffered Saline

Dispersion of nanoalumina in normal saline (NS) and phosphate buffered saline (PBS) was studied. The effects of different dispersing methods were investigated. The results showed nanoalumina was better dispersed in NS than PBS. And sonication was a more effective method that helped deaggregation compared with vortex oscillation. Finally, the influence of sonication time on the particle size and the stability of the sonicated NS suspension were studied using dynamic light scattering. The aggregation size was decreased to about 130 nm after ten-minute sonication and maintained when increasing sonication time. The particles would aggregate again during the storing time. The results of this study need to be taken into account prior to dosing in nanoalumina toxicology studies.

Dynamic light scattering from gels in a poor solvent

1978 ◽  
Vol 39 (9) ◽  
pp. 955-960 ◽  
Author(s):  
E. Geissler ◽  
A.M. Hecht
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Poor Solvent
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