scholarly journals Structural and magnetic characteristics of carboxymethyl dextran coated magnetic nanoparticles: From characterization to immobilization application

2020 ◽  
Vol 148 ◽  
pp. 104481 ◽  
Author(s):  
Katja Vasić ◽  
Željko Knez ◽  
Elizaveta A. Konstantinova ◽  
Alexander I. Kokorin ◽  
Sašo Gyergyek ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Characteristics ◽  
Carboxymethyl Dextran

(Carboxymethyl-Dextran)-Modified Magnetic Nanoparticles Conjugated to Octreotide for MRI Applications

2010 ◽  
Vol 2010 (34) ◽  
pp. 5455-5461 ◽  
Author(s):  
Guo-Cheng Han ◽  
Yang Ouyang ◽  
Xue-Ying Long ◽  
Yu Zhou ◽  
Meng Li ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Modified Magnetic Nanoparticles ◽  
Carboxymethyl Dextran

scholarly journals Epoxy Functionalized Carboxymethyl Dextran Magnetic Nanoparticles for Immobilization of Alcohol Dehydrogenase

2020 ◽  
Vol 67 (4) ◽  
pp. 1172-1179
Author(s):  
Katja Vasić ◽  
Željko Knez ◽  
Sanjay Kumar ◽  
Jitendra K. Pandey ◽  
Maja Leitgeb
Keyword(s):  
Magnetic Nanoparticles ◽  
Alcohol Dehydrogenase ◽  
Residual Activity ◽  
Enzyme Concentration ◽  
Process Conditions ◽  
Microbial Inhibition ◽  
Ft Ir ◽  
Cross Linker ◽  
And Staphylococcus Aureus ◽  
Carboxymethyl Dextran

Microbial inhibition of carboxymethyl dextran (CMD) magnetic nanoparticles (MNPs) was investigated on two different bacterial cultures, Escherichia coli and Staphylococcus aureus, where inhibition properties of CMD-MNPs were confirmed, while uncoated MNPs exhibited no inhibition properties. To such CMD-MNPs, enzyme alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae was immobilized. Later on, CMD-MNPs were functionalized, using an epoxide cross-linker epiclorohydrin (EClH) for another option of ADH immobilization. Residual activities of immobilized ADH onto epoxy functionalized and non-functionalized CMD-MNPs were determined. Effect of cross-linker concentration, temperature of immobilization and enzyme concentration on residual activities of immobilized ADH were determined, as well. With optimal process conditions (4% (v/v) EClH, 4 °C and 0.02 mg/mL of ADH), residual activity of immobilized ADH was 90%. Such immobilized ADH was characterized using FT-IR, SEM and DLS analysis.

The effect of grafting method on the colloidal stability and in vitro cytotoxicity of carboxymethyl dextran coated magnetic nanoparticles

2010 ◽  
Vol 20 (39) ◽  
pp. 8539 ◽  
Author(s):  
Mar Creixell ◽  
Adriana P. Herrera ◽  
Magda Latorre-Esteves ◽  
Vanessa Ayala ◽  
Madeline Torres-Lugo ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Colloidal Stability ◽  
In Vitro Cytotoxicity ◽  
Carboxymethyl Dextran

scholarly journals Immobilization of alcohol dehydrogenase from Saccharomyces cerevisiae onto carboxymethyl dextran-coated magnetic nanoparticles: a novel route for biocatalyst improvement via epoxy activation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Katja Vasić ◽  
Željko Knez ◽  
Maja Leitgeb
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Magnetic Nanoparticles ◽  
Alcohol Dehydrogenase ◽  
Rotation Speed ◽  
Enzyme Concentration ◽  
Novel Method ◽  
Activating Agent ◽  
Epoxy Groups ◽  
Thermal Stability Of ◽  
Carboxymethyl Dextran

Abstract A novel method is described for the immobilization of alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae onto carboxymethyl dextran (CMD) coated magnetic nanoparticles (CMD-MNPs) activated with epoxy groups, using epichlorohydrin (EClH). EClH was used as an activating agent to bind ADH molecules on the surface of CMD-MNPs. Optimal immobilization conditions (activating agent concentration, temperature, rotation speed, medium pH, immobilization time and enzyme concentration) were set to obtain the highest expressed activity of the immobilized enzyme. ADH that was immobilized onto epoxy-activated CMD-MNPs (ADH-CMD-MNPs) maintained 90% of the expressed activity. Thermal stability of ADH-CMD-MNPS after 24 h at 20 °C and 40 °C yielded 79% and 80% of initial activity, respectively, while soluble enzyme activity was only 19% at 20 °C and the enzyme was non-active at 40 °C. Expressed activity of ADH-CMD-MNPs after 21 days of storage at 4 °C was 75%. Kinetic parameters (KM, vmax) of soluble and immobilized ADH were determined, resulting in 125 mM and 1.2 µmol/min for soluble ADH, and in 73 mM and 4.7 µmol/min for immobilized ADH.

scholarly journals Magnetic Nanoparticles with High Specific Absorption Rate at Low Alternating Magnetic Field

Nano LIFE ◽  
2015 ◽  
Vol 05 (02) ◽  
pp. 1550002 ◽  
Author(s):  
K. Kekalo ◽  
I. Baker ◽  
R. Meyers ◽  
J. Shyong
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Absorption Rate ◽  
Specific Absorption Rate ◽  
Alternating Magnetic Field ◽  
Hyperthermia Treatment ◽  
Specific Absorption ◽  
New Type ◽  
Carboxymethyl Dextran

This paper describes the synthesis and properties of a new type of magnetic nanoparticle (MNP) for use in the hyperthermia treatment of tumors. These particles consist of 2–4 nm crystals of gamma- Fe 2 O 3 gathered in 20–40 nm aggregates with a coating of carboxymethyl-dextran, producing a zetasize of 110–120 nm. Despite their very low saturation magnetization (1.5–6.5 emu/g), the specific absorption rate (SAR) of the nanoparticles is 22–200 W/g at applied alternating magnetic field (AMF) with strengths of 100–500 Oe at a frequency of 160 kHz.

Magnetic Characterization of CoFe2O4 Nanoparticles

2003 ◽  
Vol 789 ◽  
Author(s):  
G. Lawes ◽  
B. Naughton ◽  
D. R. Clark ◽  
A. P. Ramirez ◽  
R. Seshadri
Keyword(s):  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Ac Susceptibility ◽  
Measurement Techniques ◽  
Anomalous Behavior ◽  
Magnetic Characteristics ◽  
Magnetic Characterization ◽  
Wide Range ◽  
Co Precipitation

We have synthesized CoFe2O4 nanoparticles with length scales ranging from 3.5 nm to 14.2 nm. We have characterized the magnetic properties of these samples using both DC and AC magnetization, and find some slightly anomalous behavior in two of the samples. We tentatively attribute these features to interactions between the magnetic nanoparticles.There is a great deal of interest in understanding the physical basis for the magnetic properties of nanoparticles in order to facilitate their incorporation into a wide range of commercial applications. By studying the magnetic characteristics of CoFe2O4 nanoparticles using bulk measurement techniques, we are able to probe the properties of both the individual nanoparticles and interactions in these systems. In this report, we discuss our magnetic characterization of a series of CoFe2O4 nanoparticles grown using an aqueous co-precipitation technique. In addition to DC magnetization at fixed fields and temperatures, we also investigated the magnetic properties using AC susceptibility measurements. The long term goal of this research is to understand interparticle interactions in magnetic nanoparticles.

Blocking Temperature of Magnetite Nanoparticles Fe3O4 Encapsulated Silicon Dioxide SiO2

2020 ◽  
Vol 855 ◽  
pp. 172-176 ◽  
Author(s):  
Togar Saragi ◽  
Hotmas D. Sinaga ◽  
Feni Rahmi ◽  
Gustiani A. Pramesti ◽  
Adi Sugiarto ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Silicon Dioxide ◽  
Temperature Dependence ◽  
Magnetite Nanoparticles ◽  
Quantum Interference ◽  
Blocking Temperature ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Superconducting Quantum Interference Device ◽  
Co Precipitation

One of the important characteristics of magnetic materials is the measurement of magnetic characteristics through Superconducting Quantum Interference Device (SQUID) especially magnetization temperature dependence M(T)ZFC and MTFC measurement. In this work, we reported magnetization temperature dependence measurements of magnetite nanoparticles without SiO2 encapsulation (Fe3O4) and magnetite nanoparticles with SiO2 encapsulation (Fe3O4.SiO2) at the application of magnetic fields of 100 Oe. The nanoparticles magnetite was synthesized by co-precipitation method. It was calculated that the blocking temperature of magnetite nanoparticles Fe3O4 without and with SiO2 encapsulation is 118.38 K and 209.03 K, respectively. The blocking temperatures of magnetic nanoparticles increase by SiO2 encapsulation.

scholarly journals Modeling The Effect of Particle Size on Magnetic Nanoparticles using Modified Ising Model

2019 ◽  
Vol 4 (1) ◽  
pp. 147
Author(s):  
Christian Fredy Naa
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Ising Model ◽  
Magnetic Characteristics ◽  
Clear Understanding ◽  
Zero Field ◽  
Surface Boundary ◽  
Doped Manganites ◽  
Effect Of Particle Size ◽  
Good Agreement

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>In this article, the Ising model has been modified to simulate the effect of particle size on magnetic nanoparticles properties especially hole-doped manganites. The objective of this research is to give an insight and clear understanding about magnetic nanoparticles especially the effect of the particle size. The model considers common accepted magnetic nanoparticles theoretical model where each particle consists of core and surface/boundary part. The model mimics the particles size as a clusters or group of spins. The spins were designated as either core or boundary particles and differs for their exchange energy. The model predicts magnetization, coercivity, hysteresis and magnetic characteristics of core and boundary of the nanoparticles. The results are in a good agreement qualitatively with experimental results. The model also gives insight to the micro-states of the spin at each clusters for zero-field-cooled experiment.</span></p></div></div></div>

scholarly journals Versatile Sulfathiazole-Functionalized Magnetic Nanoparticles as Catalyst in Oxidation and Alkylation Reactions

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 348 ◽  
Author(s):  
Ostovar ◽  
Rodríguez-Padrón ◽  
Saberi ◽  
Balu ◽  
Luque
Keyword(s):  
Magnetic Nanoparticles ◽  
Catalytic Properties ◽  
Surface Modifications ◽  
Catalytic Performance ◽  
Industrial Applications ◽  
Catalyst Design ◽  
Magnetic Characteristics ◽  
Microwave Assisted ◽  
Functionalized Magnetic Nanoparticles ◽  
Alkylation Reactions

Catalyst design and surface modifications of magnetic nanoparticles have become attractive strategies in order to optimize catalyzed organic reactions for industrial applications. In this work, silica-coated magnetic nanoparticles with a core-shell type structure were prepared. The obtained material was successfully functionalized with sulfathiazole groups, which can enhance its catalytic features. The material was fully characterized, using a multi-technique approach. The catalytic performance of the as-synthesized material was evaluated in 1) the oxidation of benzyl alcohol to benzaldehyde and 2) the microwave-assisted alkylation of toluene with benzyl chloride. Remarkable conversion and selectivity were obtained for both reactions and a clear improvement of the catalytic properties was observed in comparison with unmodified γ-Fe2O3/SiO2 and γ-Fe2O3. Noticeably, the catalyst displayed outstanding magnetic characteristics which facilitated its recovery and reusability.

Preparation, characterization and MRI application of carboxymethyl dextran coated magnetic nanoparticles

2011 ◽  
Vol 257 (15) ◽  
pp. 6711-6717 ◽  
Author(s):  
G. Liu ◽  
R.Y. Hong ◽  
L. Guo ◽  
Y.G. Li ◽  
H.Z. Li
Keyword(s):  
Magnetic Nanoparticles ◽  
Carboxymethyl Dextran
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