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Polymer/Iron Oxide Nanoparticle Composites--A Straight Forward and Scalable Synthesis Approach.

Sommertune J, Sugunan A, Ahniyaz A, Bejhed RS, Sarwe A, Johansson C, Balceris C, Ludwig F, Posth O, Fornara A - Int J Mol Sci (2015)

Bottom Line: Multi-core particles were obtained within the Z-average size range of 130 to 340 nm.With the aim to combine the fast room temperature magnetic relaxation of small individual cores with high magnetization of the ensemble of SPIONs, we used small (<10 nm) core nanoparticles.The performed synthesis is highly flexible with respect to the choice of polymer and SPION loading and gives rise to multi-core particles with interesting magnetic properties and magnetic resonance imaging (MRI) contrast efficacy.

View Article: PubMed Central - PubMed

Affiliation: SP, Technical Research Institute of Sweden, Box 5607, SE-114 86 Stockholm, Sweden. jens.sommertune@sp.se.

ABSTRACT
Magnetic nanoparticle systems can be divided into single-core nanoparticles (with only one magnetic core per particle) and magnetic multi-core nanoparticles (with several magnetic cores per particle). Here, we report multi-core nanoparticle synthesis based on a controlled precipitation process within a well-defined oil in water emulsion to trap the superparamagnetic iron oxide nanoparticles (SPION) in a range of polymer matrices of choice, such as poly(styrene), poly(lactid acid), poly(methyl methacrylate), and poly(caprolactone). Multi-core particles were obtained within the Z-average size range of 130 to 340 nm. With the aim to combine the fast room temperature magnetic relaxation of small individual cores with high magnetization of the ensemble of SPIONs, we used small (<10 nm) core nanoparticles. The performed synthesis is highly flexible with respect to the choice of polymer and SPION loading and gives rise to multi-core particles with interesting magnetic properties and magnetic resonance imaging (MRI) contrast efficacy.

No MeSH data available.


Related in: MedlinePlus

Real and imaginary components of the AC susceptibility versus frequency of samples A and B (left y-scale), and FeraSpin™-R (right y-scale) at room temperature. No magnetic relaxation peak is observed for samples A and B. As a comparison, a commercial multi-core sample, FeraSpin™-R from nanoPET (right scale), shows a well-developed relaxation peak, indicating a Brownian relaxation frequency in the range of 1 kHz.
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ijms-16-19752-f009: Real and imaginary components of the AC susceptibility versus frequency of samples A and B (left y-scale), and FeraSpin™-R (right y-scale) at room temperature. No magnetic relaxation peak is observed for samples A and B. As a comparison, a commercial multi-core sample, FeraSpin™-R from nanoPET (right scale), shows a well-developed relaxation peak, indicating a Brownian relaxation frequency in the range of 1 kHz.

Mentions: In Figure 9, χ′ and χ″ are shown versus frequency at room temperature for Samples A and B and compared to a commercially available multicore sample, FeraSpin™-R (from nanoPET Pharma GmbH, Berlin, Germany). Samples A and B show almost identical response with a constant χ′ and χ′ʹ being close to zero in the whole measured frequency range up to 10 MHz. This is typical of fast Néel relaxation where the excitation frequency is much smaller than the Néel relaxation frequency (=1/(2πτN), where τN is the Néel relaxation time). From previous measurements on similar iron oxide nanoparticles we conclude that these results are in agreement with the TEM data of nanocrystal sizes in the range of 8–9 nm. The value of χ′, normalized with the iron concentration, are the same for sample A and B, indicating almost the same nanocrystal size distribution and intrinsic saturation magnetization of sample A and B which are consistent with the TEM and magnetization versus field analysis. As expected, the ACS versus frequency data of the core nanocrystals (data not shown) also did not show any features in the entire range of frequencies.


Polymer/Iron Oxide Nanoparticle Composites--A Straight Forward and Scalable Synthesis Approach.

Sommertune J, Sugunan A, Ahniyaz A, Bejhed RS, Sarwe A, Johansson C, Balceris C, Ludwig F, Posth O, Fornara A - Int J Mol Sci (2015)

Real and imaginary components of the AC susceptibility versus frequency of samples A and B (left y-scale), and FeraSpin™-R (right y-scale) at room temperature. No magnetic relaxation peak is observed for samples A and B. As a comparison, a commercial multi-core sample, FeraSpin™-R from nanoPET (right scale), shows a well-developed relaxation peak, indicating a Brownian relaxation frequency in the range of 1 kHz.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581323&req=5

ijms-16-19752-f009: Real and imaginary components of the AC susceptibility versus frequency of samples A and B (left y-scale), and FeraSpin™-R (right y-scale) at room temperature. No magnetic relaxation peak is observed for samples A and B. As a comparison, a commercial multi-core sample, FeraSpin™-R from nanoPET (right scale), shows a well-developed relaxation peak, indicating a Brownian relaxation frequency in the range of 1 kHz.
Mentions: In Figure 9, χ′ and χ″ are shown versus frequency at room temperature for Samples A and B and compared to a commercially available multicore sample, FeraSpin™-R (from nanoPET Pharma GmbH, Berlin, Germany). Samples A and B show almost identical response with a constant χ′ and χ′ʹ being close to zero in the whole measured frequency range up to 10 MHz. This is typical of fast Néel relaxation where the excitation frequency is much smaller than the Néel relaxation frequency (=1/(2πτN), where τN is the Néel relaxation time). From previous measurements on similar iron oxide nanoparticles we conclude that these results are in agreement with the TEM data of nanocrystal sizes in the range of 8–9 nm. The value of χ′, normalized with the iron concentration, are the same for sample A and B, indicating almost the same nanocrystal size distribution and intrinsic saturation magnetization of sample A and B which are consistent with the TEM and magnetization versus field analysis. As expected, the ACS versus frequency data of the core nanocrystals (data not shown) also did not show any features in the entire range of frequencies.

Bottom Line: Multi-core particles were obtained within the Z-average size range of 130 to 340 nm.With the aim to combine the fast room temperature magnetic relaxation of small individual cores with high magnetization of the ensemble of SPIONs, we used small (<10 nm) core nanoparticles.The performed synthesis is highly flexible with respect to the choice of polymer and SPION loading and gives rise to multi-core particles with interesting magnetic properties and magnetic resonance imaging (MRI) contrast efficacy.

View Article: PubMed Central - PubMed

Affiliation: SP, Technical Research Institute of Sweden, Box 5607, SE-114 86 Stockholm, Sweden. jens.sommertune@sp.se.

ABSTRACT
Magnetic nanoparticle systems can be divided into single-core nanoparticles (with only one magnetic core per particle) and magnetic multi-core nanoparticles (with several magnetic cores per particle). Here, we report multi-core nanoparticle synthesis based on a controlled precipitation process within a well-defined oil in water emulsion to trap the superparamagnetic iron oxide nanoparticles (SPION) in a range of polymer matrices of choice, such as poly(styrene), poly(lactid acid), poly(methyl methacrylate), and poly(caprolactone). Multi-core particles were obtained within the Z-average size range of 130 to 340 nm. With the aim to combine the fast room temperature magnetic relaxation of small individual cores with high magnetization of the ensemble of SPIONs, we used small (<10 nm) core nanoparticles. The performed synthesis is highly flexible with respect to the choice of polymer and SPION loading and gives rise to multi-core particles with interesting magnetic properties and magnetic resonance imaging (MRI) contrast efficacy.

No MeSH data available.


Related in: MedlinePlus