Particle size- and concentration-dependent separation of magnetic nanoparticles

2017 ◽  
Vol 427 ◽  
pp. 320-324 ◽  
Author(s):  
Kerstin Witte ◽  
Knut Müller ◽  
Cordula Grüttner ◽  
Fritz Westphal ◽  
Christer Johansson
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles

Influence of ultrasonically assisted synthesis on particle size of magnetic nanoparticles

2013 ◽  
Vol 74 (10) ◽  
pp. 1426-1432 ◽  
Author(s):  
Burcu Küçük ◽  
Necati Özkan ◽  
Mürvet Volkan
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles

Tailoring Local Hysteresis in Small Clusters of Dipolar Interacting Magnetic Nanoparticles

NANO ◽  
2021 ◽  
pp. 2150104
Author(s):  
Manish Anand
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Hysteresis Loop ◽  
Cluster Size ◽  
Interaction Strength ◽  
Dipolar Interaction ◽  
Dipolar Field ◽  
Area Formula ◽  
Loop Area ◽  
Hysteresis Loop Area

Using first-principle calculations and kinetic Monte Carlo simulation, we study the local and averaged hysteresis in tiny clusters of [Formula: see text] magnetic nanoparticles (MNPs) or [Formula: see text]-mers. We also analyze the variation of local dipolar field acting on the constituent nanoparticles as a function of the external magnetic field. The dipolar interaction is found to promote chain-like arrangement in such a cluster. Irrespective of cluster size, the local hysteresis response depends strongly on the corresponding dipolar field acting on a nanoparticle. In a small [Formula: see text]-mer, there is a wide variation in local hysteresis as a function of nanoparticle position. On the other hand, the local hysteresis is more uniform for larger [Formula: see text]-mer, except for MNPs at the boundary. In the case of superparamagnetic nanoparticle and weak dipolar interaction, the local hysteresis loop area [Formula: see text] is minimal and depends weakly on the [Formula: see text]-mer size. While for ferromagnetic counterpart, [Formula: see text] is considerably large even for weakly interacting MNPs. The value of [Formula: see text] is found to be directly proportional to the dipolar field acting on the nanoparticle. The dipolar interaction and [Formula: see text]-mer size also enhance the coercivity and remanence. There is always an increase in [Formula: see text] with cluster size and dipolar interaction strength. Similarly, the averaged hysteresis loop area [Formula: see text] also depends strongly on the [Formula: see text]-mer size, particle size and dipolar interaction strength. [Formula: see text] and [Formula: see text] always increase with [Formula: see text]-mer size and dipolar interaction strength. Interestingly, the value of [Formula: see text] saturates for [Formula: see text] and considerable dipolar interaction irrespective of particle size. We believe that this work would help understand the intricate role of dipolar interaction on hysteresis and the organizational structure of MNPs and their usage in drug delivery and hyperthermia applications.

scholarly journals Particle Size Dependent Photodynamic Anticancer Activity of Hematoporphyrin-Conjugated Fe3O4Particles

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ki Chang Nam ◽  
Kyong-Hoon Choi ◽  
Kyu-Dong Lee ◽  
Jung Hyun Kim ◽  
Jin-Seung Jung ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Anticancer Activity ◽  
Size Dependent ◽  
Anticancer Effects ◽  
Anticancer Treatment ◽  
Wet Chemical ◽  
Biological Entities ◽  
Technical Solutions ◽  
Better Than

Nanomedicine, which involves the use of magnetic nanoparticles such as Fe3O4, has provided novel technical solutions for cancer diagnosis and treatment. Most studies in nanomedicine have focused on the use of nanoparticles with magnetic resonance imaging and hyperthermia. However, to achieve optimum anticancer effects, it is important to understand the physicochemical properties of magnetic nanoparticles and their interactions with biological entities. In this study, we synthesized Fe3O4particles of various sizes and conjugated them with hematoporphyrin (HP) molecules by using a simple surface-modification method. HP molecules were covalently bound to the surface of Fe3O4particles by a wet chemical process, resulting in Fe3O4@HPs particles that were uniform in size, were nontoxic, and exhibited strong anticancer effects on human prostate cancer (PC-3) and breast cancer (MDA-MB-231) cell lines. The Fe3O4@HPs particles showed remarkable and efficient photodynamic anticancer activity, depending on their particle size. These results indicate that all size of Fe3O4@HPs particles can be useful for photodynamic anticancer therapy, although the smaller size is better than the larger size and further studies will be needed to confirm the potential for clinical anticancer treatment.

IMMOBILIZATION OF BSA ON DENDRIMER FUNCTIONALIZED MAGNETIC NANOPARTICLES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 919-923 ◽  
Author(s):  
S. CHANDRA ◽  
N. NITHYAMATHI ◽  
P. SELVAMANI ◽  
D. BAHADUR
Keyword(s):  
Particle Size ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Ftir Spectroscopy ◽  
Magnetite Nanoparticles ◽  
Bovine Serum ◽  
Oxide Nanoparticles ◽  
Functionalized Magnetic Nanoparticles

Iron oxide nanoparticles were prepared and functionalized by succinamide based dendrimer. The resultant particles were characterized by XRD, VSM, and FTIR spectroscopy. The results indicate that the dendrimers has effectively functionalized the magnetite nanoparticles which remain dispersive and exhibited super-paramagnetism with a magnetization value of 33.2 emu/g in a field of 2T. Mean particle size as calculated from the AFM was found to be ~ 23 nm. Bovine serum albumin was immobilized on the magnetic nanoparticles as was confirmed by the FTIR results.

Characterization of solid magnetic nanoparticles by means of solid sampling high resolution continuum source electrothermal atomic absorption spectrometry

2016 ◽  
Vol 31 (12) ◽  
pp. 2391-2398 ◽  
Author(s):  
E. Vereda Alonso ◽  
M. M. López Guerrero ◽  
M. T. Siles Cordero ◽  
J. M. Cano Pavón ◽  
A. García de Torres
Keyword(s):  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Iron Concentration ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Direct Determination ◽  
Absorption Spectrometry ◽  
Solid Sampling ◽  
Continuum Source

Direct determination of iron concentration and particle size of solid MNPs using HR CS GFAAS.

Mn0.2Co0.8Fe2O4 and encapsulated Mn0.2Co0.8Fe2O4/SiO2 magnetic nanoparticles for efficient Pb2+ removal from aqueous solution

2019 ◽  
Vol 80 (2) ◽  
pp. 377-386
Author(s):  
Kamal R. Awad ◽  
M. M. S. Wahsh ◽  
Shaimaa T. El-Wakeel ◽  
Kingsley I. Ochiabuto ◽  
A. G. M. Othman ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Solution Ph ◽  
Transition Electron Microscopy ◽  
Auto Combustion ◽  
Langmuir Isotherm Model ◽  
Modified Stöber Method

Abstract Sol-gel auto-combustion technique was used to synthesize spinel ferrite nanoparticles of Mn0.2Co0.8Fe2O4 (MCF). Using the modified Stöber method, these magnetic nanoparticles were encapsulated with silica to form the core/shell Mn0.2Co0.8Fe2O4/SiO2 (MCFS). The phase composition, morphology, particle size, and saturation magnetization of the encapsulated nanoparticles were studied using X-ray diffraction (XRD), high resolution-transition electron microscopy (HR-TEM), and vibrating sample magnetometer (VSM). HR-TEM images indicated that particle size of the nanoparticles ranged from 15 to 40 nm, and VSM measurements showed that Ms of uncoated and coated samples were 65.668 emu/g and 61.950 emu/g and the Hc values were 2,151.9 Oe and 2,422.0 Oe, respectively. The effects of metal concentration, solution pH, contact time, and adsorbent dose of the synthesized nanoparticles on lead (Pb2+) ions removal from an aqueous solution were investigated. Based on Langmuir isotherm model, the results for peak adsorption capacity of the adsorbent under optimal conditions was 250.5 mg/g and 247 mg/g for MCF and MCFS, respectively. We concluded that Pb2+ adsorption occurred via a chemisorption mechanism based on the analysis of adsorption kinetics. The adsorbents displayed consistent adsorption efficiencies following three cycles of regeneration, indicating that these magnetic nanoparticles are promising candidates for wastewater purification.

scholarly journals The Effect of Electrode Topography on the Magnetic Properties and MRI Application of Electrochemically-Deposited, Synthesized, Cobalt-Substituted Hydroxyapatite

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 200 ◽  
Author(s):  
Wei-Chun Lin ◽  
Chun-Chao Chuang ◽  
Chen-Jung Chang ◽  
Ya-Hsu Chiu ◽  
Cheng-Ming Tang
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Titanium Dioxide ◽  
Magnetic Nanoparticles ◽  
Cobalt Oxide ◽  
Crystal Size ◽  
Image Contrast ◽  
Potential Candidate ◽  
Hydroxyapatite Nanoparticles ◽  
Mri Image

Magnetic nanoparticles are used to enhance the image contrast of magnetic resonance imaging (MRI). However, the development of magnetic nanoparticles with a low dose/high image contrast and non-toxicity is currently a major challenge. In this study, cobalt-substituted hydroxyapatite nanoparticles deposited on titanium (Ti-CoHA) and cobalt-substituted hydroxyapatite nanoparticles deposited on titanium dioxide nanotubes (TNT-CoHA) were synthesized by the electrochemical deposition method. The particle sizes of Ti-CoHA and TNT-CoHA were 418.6 nm and 127.5 nm, respectively, as observed using FE-SEM. It was shown that CoHA can be obtained with a smaller particle size using a titanium dioxide nanotube (TNT) electrode plate. However, the particle size of TNT-CoHA is smaller than that of Ti-CoHA. The crystal size of the internal cobalt oxide of CoHA was calculated by using an XRD pattern. The results indicate that the crystal size of cobalt oxide in TNT-CoHA is larger than that of the cobalt oxide in Ti-CoHA. The larger crystal size of the cobalt oxide in TNT-CoHA makes the saturation magnetization (Ms) of TNT-CoHA 12.6 times higher than that of Ti-CoHA. The contrast in MRIs is related to the magnetic properties of the particles. Therefore, TNT-CoHA has good image contrast at low concentrations in T2 images. The relaxivity coefficient of the CoHA was higher for TNT-CoHA (340.3 mM−1s−1) than Ti-CoHA (211.7 mM−1s−1), and both were higher than the commercial iron nanoparticles (103.0 mM−1s−1). We showed that the TNT substrate caused an increase in the size of the cobalt oxide crystal of TNT-CoHA, thus effectively improving the magnetic field strength and MRI image recognition. It was also shown that the relaxivity coefficient rose with the Ms. Evaluation of biocompatibility of CoHA using human osteosarcoma cells (MG63) indicated no toxic effects. On the other hand, CoHA had an excellent antibacterial effect, as shown by E. coli evaluation, and the effect of TNT-CoHA powder was higher than that of Ti-CoHA powder. In summary, TNT-CoHA deposited electrochemically on the TNT substrates can be considered as a potential candidate for the application as an MRI contrast agent. This paper is a comparative study of how different electrode plates affect the magnetic and MRI image contrast of cobalt-substituted hydroxyapatite (CoHA) nanomaterials.

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