scholarly journals Synthesis of Janus plasmonic–magnetic, star–sphere nanoparticles, and their application in SERS detection

2016 ◽  
Vol 191 ◽  
pp. 47-59 ◽  
Author(s):  
Javier Reguera ◽  
Dorleta Jiménez de Aberasturi ◽  
Naomi Winckelmans ◽  
Judith Langer ◽  
Sara Bals ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spatial Distribution ◽  
Iron Oxide ◽  
Electron Tomography ◽  
Magnetic Star ◽  
Specific Interactions ◽  
Unique Combination ◽  
Clear Separation ◽  
Janus Nanoparticles ◽  
Sers Detection

Multicomponent nanoparticles are of particular interest due to a unique combination of properties at the nanoscale, which make them suitable for a wide variety of applications. Among them, Janus nanoparticles, presenting two distinct surface regions, can lead to specific interactions with interfaces, biomolecules, membranes etc. We report the synthesis of Janus nanoparticles comprising iron oxide nanospheres and gold nanostars, through two consecutive seed-mediated-growth steps. Electron tomography combining HAADF-STEM and EDX mapping has been performed to evaluate the spatial distribution of the two components of the nanoparticle, showing their clear separation in a Janus morphology. Additionally, SERS measurements assisted by magnetic separation were carried out to assess the application of combined plasmonic and magnetic properties for sensing.

scholarly journals Magnetic properties of surface sediments in Schirmacher Oasis, East Antarctica: spatial distribution and controlling factors

2020 ◽  
Author(s):  
Anish Kumar Warrier ◽  
Joju George Sebastian ◽  
K. Amrutha ◽  
A. S. Yamuna Sali ◽  
B. S. Mahesh ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Grain Size ◽  
Magnetic Properties ◽  
Spatial Distribution ◽  
Iron Oxide ◽  
Iron Oxides ◽  
Remanent Magnetization ◽  
Principal Component ◽  
East Antarctica ◽  
Schirmacher Oasis

Abstract Purpose We investigated the magnetic properties (abundance, grain size, and mineralogy) of iron oxides present in Lake L-55 sediments, Schirmacher Oasis, East Antarctica, with an aim to understand their spatial distribution and the underlying mechanisms that control their formation and distribution. Methods Twenty-five surficial sediments retrieved from different parts of Lake L-55 were subjected to the entire range of environmental magnetic (magnetic susceptibility, anhysteretic remanent magnetization (ARM), isothermal remanent magnetization (IRM)) measurements (at different field strengths). Inter-parametric ratios (χARM/SIRM, χARM/χlf, χARM/χfd, IRM20 mT/SIRM, IRM20 mT/ARM, S-ratio, L-ratio) provided insights into the magnetic properties (abundance, grain size, and mineralogy of iron oxides). Scanning electron microscopic-energy dispersive X-ray spectroscopic (SEM-EDS) analysis was performed on magnetic extracts from a few sediments. Besides, organic matter (%) was also calculated for the sediment samples. Principal component analysis was performed to gain information on the presence of different components and their relative dominance. Results The iron oxides are strongly magnetic (high values of concentration-dependent parameters). The principal iron oxide is magnetite (S-ratio > 0.90) which is coarse-grained (multi-domain (MD) and stable single-domain (SSD) grains), and there is no influence of authigenic greigite, bacterial magnetite, and anthropogenic magnetite. The mineralogy is confirmed by SEM-EDS data. The iron oxides are of different grain sizes, and their contribution is in the order of MD > SSD > SP as shown by the principal component analysis. Pedogenic iron oxide minerals seem to be present in the samples whose formation is due to the oxidation of magnetite into hematite. However, they are of SSD size and not SP, suggesting that the intensity of pedogenesis is not sufficient to form SP grains. Conclusion The iron oxide minerals are mainly terrigenous, and the biogenic activity within the lake is not sufficient to modify the ferrimagnetic minerals. Spatial distribution patterns suggest the non-uniform distribution of magnetite/titanomagnetite of varying sizes in the lake basin which is transported by both melt water streams and winds.

scholarly journals Reversible magnetism switching of iron oxide nanoparticle dispersions by controlled agglomeration

2021 ◽  
Author(s):  
Stephan Müssig ◽  
Björn Kuttich ◽  
Florian Fidler ◽  
Daniel Haddad ◽  
Susanne Wintzheimer ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Light Scattering ◽  
Superparamagnetic Iron Oxide ◽  
Iron Oxide Nanoparticle ◽  
Oxide Nanoparticles ◽  
X Ray ◽  
X Ray Scattering ◽  
Nanoparticle Dispersions ◽  
Oxide Nanoparticle

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...

scholarly journals Properties of Silicone Rubber-Based Composites Reinforced with Few-Layer Graphene and Iron Oxide or Titanium Dioxide

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1550
Author(s):  
Vineet Kumar ◽  
Anuj Kumar ◽  
Minseok Song ◽  
Dong-Joo Lee ◽  
Sung-Soo Han ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Titanium Dioxide ◽  
Iron Oxide ◽  
Stress Relaxation ◽  
Silicone Rubber ◽  
Room Temperature ◽  
Relaxation Rates ◽  
Layer Graphene ◽  
Few Layer Graphene ◽  
Mechanical Actuation

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.

scholarly journals Induction of Axonal Outgrowth in Mouse Hippocampal Neurons via Bacterial Magnetosomes

2021 ◽  
Vol 22 (8) ◽  
pp. 4126
Author(s):  
Sara De Vincentiis ◽  
Alessandro Falconieri ◽  
Frank Mickoleit ◽  
Valentina Cappello ◽  
Dirk Schüler ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Hippocampal Neurons ◽  
Magnetotactic Bacteria ◽  
Oxide Nanoparticles ◽  
Axonal Outgrowth ◽  
Mechanical Forces ◽  
Internalization Process ◽  
Oxide Crystals ◽  
Stimulation Of

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.

Comparative study on the magnetic properties of iron oxide nanoparticles loaded on mesoporous silica and carbon materials with different structure

2009 ◽  
Vol 121 (1-3) ◽  
pp. 178-184 ◽  
Author(s):  
Sher Alam ◽  
Chokkalingam Anand ◽  
Radhakrishnan Logudurai ◽  
Veerappan V. Balasubramanian ◽  
Katsuhiko Ariga ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Mesoporous Silica ◽  
Comparative Study ◽  
Iron Oxide Nanoparticles ◽  
Carbon Materials ◽  
Oxide Nanoparticles

Photo-fluorescent and magnetic properties of iron oxide nanoparticles for biomedical applications

Nanoscale ◽  
2015 ◽  
Vol 7 (18) ◽  
pp. 8209-8232 ◽  
Author(s):  
Donglu Shi ◽  
M. E. Sadat ◽  
Andrew W. Dunn ◽  
David B. Mast
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Physical Properties ◽  
Iron Oxide Nanoparticles ◽  
Basic Science ◽  
Biomedical Applications ◽  
Oxide Nanoparticles ◽  
Nanometer Range

Iron oxide exhibits fascinating physical properties especially in the nanometer range, not only from the standpoint of basic science, but also for a variety of engineering, particularly biomedical applications.

The fabrication and magnetic properties of nanowire-like iron oxide

2004 ◽  
Vol 16 (25) ◽  
pp. 4541-4548 ◽  
Author(s):  
L Y Zhang ◽  
D S Xue ◽  
X F Xu ◽  
A B Gui ◽  
C X Gao
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide

Enhanced Collective Magnetic Properties in 2D Monolayers of Iron Oxide Nanoparticles Favored by Local Order and Local 1D Shape Anisotropy

Langmuir ◽  
2016 ◽  
Vol 32 (6) ◽  
pp. 1621-1628 ◽  
Author(s):  
Delphine Toulemon ◽  
Yu Liu ◽  
Xavier Cattoën ◽  
Cédric Leuvrey ◽  
Sylvie Bégin-Colin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Shape Anisotropy ◽  
Local Order ◽  
Oxide Nanoparticles
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