scholarly journals Raman spectroscopy to unravel the magnetic properties of iron oxide nanocrystals for bio-related applications

2019 ◽  
Vol 1 (6) ◽  
pp. 2086-2103 ◽  
Author(s):  
Martín Testa-Anta ◽  
Miguel A. Ramos-Docampo ◽  
Miguel Comesaña-Hermo ◽  
Beatriz Rivas-Murias ◽  
Verónica Salgueiriño

Raman spectroscopy is a very valuable and fast-performance tool to gain insight first into the different iron oxide phases present in nanoparticles, to correlate then the magnetic properties with potential bio-related applications.

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4147
Author(s):  
Vera Serga ◽  
Regina Burve ◽  
Mikhail Maiorov ◽  
Aija Krumina ◽  
Ramūnas Skaudžius ◽  
...  

Interest in magnetic nanoparticles is primarily due to their practical use. In this work, for the production of nanocrystalline powders of pure and gadolinium doped iron oxides, the extraction-pyrolytic method (EPM) was used. As a precursor, either iron-containing extract (iron (III) caproate in caproic acid) or its mixture with gadolinium-containing extract (gadolinium (III) valerate in valeric acid) was used. The mixed precursor contained 0.5 mol %, 2.5 mol %, 12.5 mol %, 50 mol %, and 75 mol % gadolinium in relation to the iron content. The formation of iron oxide phases, depending on the preparation conditions, was investigated. According to the results obtained, it was demonstrated that the presence of more than 2.5 mol % gadolinium additive in the mixed precursor inhibits the magnetite-to-hematite transformation process during thermal treatment. Produced samples were characterized by XRD and SEM methods, and the magnetic properties were studied.


2020 ◽  
pp. 30-35
Author(s):  
Silviya Boycheva ◽  
Denitza Zgureva

Coal fly ash generated in Thermal Power Plants is utilized for synthesis of zeolites due to its aluminosilicate composition. The highest degree of zeolitization of coal ash in a particular zeolite phase is achieved by double-stage synthesis involving successive alkaline melting and hydrothermal activation of the reaction mixtures, while the uniform distribution of the iron oxides transferred from the raw coal ash is ensured by ultrasonic treatment. However, the applied melting step results in the oxidation of the magnetic iron oxide phases to non-magnetic ones, which results in the loss of magnetic properties of the resulting materials. The present investigation focuses on an improved double- stage synthesis procedure by the addition of raw coal ash containing magnetite between high temperature and low temperature processing. In this way, the magnetic phase is retained in the final product and the magnetic properties of the zeolites are preserved, which is important for their application in the adsorption of pollutants from wastewater.


2017 ◽  
Vol 26 (8) ◽  
pp. 087502
Author(s):  
A Asif ◽  
M Hassan ◽  
S Riaz ◽  
S Naseem ◽  
SS Hussain

2010 ◽  
Vol 604 (7-8) ◽  
pp. 679-685 ◽  
Author(s):  
Maike Lübbe ◽  
Alexander M. Gigler ◽  
Robert W. Stark ◽  
Wolfgang Moritz

RSC Advances ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 390-396
Author(s):  
David González-Alonso ◽  
Jesús González ◽  
Helena Gavilán ◽  
Jeppe Fock ◽  
Lunjie Zeng ◽  
...  

We provide direct evidence of a Verwey transition in a nanoparticle ensemble of mixed iron-oxide phases via temperature-dependent Raman spectroscopy.


2021 ◽  
Author(s):  
Stephan Müssig ◽  
Björn Kuttich ◽  
Florian Fidler ◽  
Daniel Haddad ◽  
Susanne Wintzheimer ◽  
...  

The controlled agglomeration of superparamagnetic iron oxide nanoparticles (SPIONs) was used to rapidly switch their magnetic properties. Small-angle X-ray scattering (SAXS) and dynamic light scattering showed that tailored iron oxide...


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1550
Author(s):  
Vineet Kumar ◽  
Anuj Kumar ◽  
Minseok Song ◽  
Dong-Joo Lee ◽  
Sung-Soo Han ◽  
...  

The increasing demand for polymer composites with novel or improved properties requires novel fillers. To meet the challenges posed, nanofillers such as graphene, carbon nanotubes, and titanium dioxide (TiO2) have been used. In the present work, few-layer graphene (FLG) and iron oxide (Fe3O4) or TiO2 were used as fillers in a room-temperature-vulcanized (RTV) silicone rubber (SR) matrix. Composites were prepared by mixing RTV-SR with nanofillers and then kept for vulcanization at room temperature for 24 h. The RTV-SR composites obtained were characterized with respect to their mechanical, actuation, and magnetic properties. Fourier-transform infrared spectroscopy (FTIR) analysis was performed to investigate the composite raw materials and finished composites, and X-ray photoelectron spectroscopy (XPS) analysis was used to study composite surface elemental compositions. Results showed that mechanical properties were improved by adding fillers, and actuation displacements were dependent on the type of nanofiller used and the applied voltage. Magnetic stress-relaxation also increased with filler amount and stress-relaxation rates decreased when a magnetic field was applied parallel to the deformation axes. Thus, this study showed that the inclusion of iron oxide (Fe3O4) or TiO2 fillers in RTV-SR improves mechanical, actuation, and magnetic properties.


2021 ◽  
Vol 22 (8) ◽  
pp. 4126
Author(s):  
Sara De Vincentiis ◽  
Alessandro Falconieri ◽  
Frank Mickoleit ◽  
Valentina Cappello ◽  
Dirk Schüler ◽  
...  

Magnetosomes are membrane-enclosed iron oxide crystals biosynthesized by magnetotactic bacteria. As the biomineralization of bacterial magnetosomes can be genetically controlled, they have become promising nanomaterials for bionanotechnological applications. In the present paper, we explore a novel application of magnetosomes as nanotool for manipulating axonal outgrowth via stretch-growth (SG). SG refers to the process of stimulation of axonal outgrowth through the application of mechanical forces. Thanks to their superior magnetic properties, magnetosomes have been used to magnetize mouse hippocampal neurons in order to stretch axons under the application of magnetic fields. We found that magnetosomes are avidly internalized by cells. They adhere to the cell membrane, are quickly internalized, and slowly degrade after a few days from the internalization process. Our data show that bacterial magnetosomes are more efficient than synthetic iron oxide nanoparticles in stimulating axonal outgrowth via SG.


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