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The influence of colloidal parameters on the specific power absorption of PAA-coated magnetite nanoparticles.

Piñeiro-Redondo Y, Bañobre-López M, Pardiñas-Blanco I, Goya G, López-Quintela MA, Rivas J - Nanoscale Res Lett (2011)

Bottom Line: The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR).A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found.These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

View Article: PubMed Central - HTML - PubMed

Affiliation: Applied Physics and Physical Chemistry Departments, University of Santiago de Compostela, Santiago de Compostela, 15782, Spain. manuel.banobre@usc.es.

ABSTRACT
The suitability of magnetic nanoparticles (MNPs) to act as heat nano-sources by application of an alternating magnetic field has recently been studied due to their promising applications in biomedicine. The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR). With this aim, the SAR of magnetic dispersions containing superparamagnetic magnetite nanoparticles bio-coated with polyacrylic acid of an average particle size of ≈10 nm has been evaluated separately by changing colloidal parameters such as the MNP concentration and the viscosity of the solvent. A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found. These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

No MeSH data available.


Related in: MedlinePlus

Evolution of the specific absorption rate (SAR) of Fe3O4@PAA NPs dispersions with solvent viscosity, η, under an external AC magnetic field of B = 15 mT and ν = 308 kHz. Solid line is a guide for the eye.
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Figure 4: Evolution of the specific absorption rate (SAR) of Fe3O4@PAA NPs dispersions with solvent viscosity, η, under an external AC magnetic field of B = 15 mT and ν = 308 kHz. Solid line is a guide for the eye.

Mentions: Figure 4 shows the evolution of SAR for PAA-coated magnetite ferrofluids with viscosity. Different values of viscosity ranging from 1 to 90 mPa s were achieved by using different solvents (water, ethylene glycol, 1-2-propanediol and poly-ethylene glycol). It is important to mention that the magnetite concentration was kept constant in all the samples, which showed a very good stability for all the solvents used. The effect of changing the solvent viscosity reveals that Brownian relaxation contribution is also significant in small SPM nanoparticles. A slight SAR increase from 36.5 to 37.3 W g-1 takes place as the solvent viscosity increases from η = 1 mP s (water) to η = 17 mP s (ethylene glycol). However, the use of solvents of higher viscosities causes significant SAR decreases. This tendency agrees with theoretical predictions [10] and experimental results found in dextran-coated magnetite ferrofluids, where a maximum SAR is observed in the interval of 1 < η < 3 mP s [24].


The influence of colloidal parameters on the specific power absorption of PAA-coated magnetite nanoparticles.

Piñeiro-Redondo Y, Bañobre-López M, Pardiñas-Blanco I, Goya G, López-Quintela MA, Rivas J - Nanoscale Res Lett (2011)

Evolution of the specific absorption rate (SAR) of Fe3O4@PAA NPs dispersions with solvent viscosity, η, under an external AC magnetic field of B = 15 mT and ν = 308 kHz. Solid line is a guide for the eye.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211476&req=5

Figure 4: Evolution of the specific absorption rate (SAR) of Fe3O4@PAA NPs dispersions with solvent viscosity, η, under an external AC magnetic field of B = 15 mT and ν = 308 kHz. Solid line is a guide for the eye.
Mentions: Figure 4 shows the evolution of SAR for PAA-coated magnetite ferrofluids with viscosity. Different values of viscosity ranging from 1 to 90 mPa s were achieved by using different solvents (water, ethylene glycol, 1-2-propanediol and poly-ethylene glycol). It is important to mention that the magnetite concentration was kept constant in all the samples, which showed a very good stability for all the solvents used. The effect of changing the solvent viscosity reveals that Brownian relaxation contribution is also significant in small SPM nanoparticles. A slight SAR increase from 36.5 to 37.3 W g-1 takes place as the solvent viscosity increases from η = 1 mP s (water) to η = 17 mP s (ethylene glycol). However, the use of solvents of higher viscosities causes significant SAR decreases. This tendency agrees with theoretical predictions [10] and experimental results found in dextran-coated magnetite ferrofluids, where a maximum SAR is observed in the interval of 1 < η < 3 mP s [24].

Bottom Line: The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR).A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found.These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

View Article: PubMed Central - HTML - PubMed

Affiliation: Applied Physics and Physical Chemistry Departments, University of Santiago de Compostela, Santiago de Compostela, 15782, Spain. manuel.banobre@usc.es.

ABSTRACT
The suitability of magnetic nanoparticles (MNPs) to act as heat nano-sources by application of an alternating magnetic field has recently been studied due to their promising applications in biomedicine. The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SAR). With this aim, the SAR of magnetic dispersions containing superparamagnetic magnetite nanoparticles bio-coated with polyacrylic acid of an average particle size of ≈10 nm has been evaluated separately by changing colloidal parameters such as the MNP concentration and the viscosity of the solvent. A remarkable decrease of the SAR values with increasing particle concentration and solvent viscosity was found. These behaviours have been discussed on the basis of the magnetic relaxation mechanisms involved.PACS: 80; 87; 87.85jf.

No MeSH data available.


Related in: MedlinePlus