Recent studies on magnetic nanoparticles (MNPs) used for Magnetic Fluid Hyperthermia treatments have shown that Brownian rotation is suppressed when they are confined within a cell. To investigate this effect we conducted a systematic study of the Specific Absorption Rate (SAR) of colloidal suspensions of MNPs in water and gels at different agarose concentration. SAR measurements were conducted by varying the frequency (f=110–990 kHz) and amplitude (up to 17 kA/m) of the applied alternating magnetic field (AMF). MNP samples with different diameter (d=10, 14, and 18 nm) were used. Our results show that Néel relaxation dominates SAR with negligible contribution from Brownian motion for smaller MNPs (d=10 nm). For the largest MNPs (d=18 nm) we observed a more significant SAR decrease in gel suspensions as compared to those in solution. In particular, when applying AMFs as the ones used in a clinical setting (16.2 kA/m at f=110 kHz), we measured SAR value of 67 W/g in solution and 25 W/g in gel. This experimental finding demonstrates that investigation of MNPs properties should be conducted in media with viscosity similar to the one found in mammalian tissues.

In-gel study of the effect of magnetic nanoparticles immobilization on their heating efficiency for application in Magnetic Fluid Hyperthermia / Avolio, Matteo; Guerrini, Andrea; Brero, Francesca; Innocenti, Claudia; Sangregorio, Claudio; Cobianchi, Marco; Mariani, Manuel; Orsini, Francesco; Arosio, Paolo; Lascialfari, Alessandro. - In: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS. - ISSN 0304-8853. - STAMPA. - 471:(2019), pp. 504-512. [10.1016/j.jmmm.2018.09.111]

In-gel study of the effect of magnetic nanoparticles immobilization on their heating efficiency for application in Magnetic Fluid Hyperthermia

Guerrini, Andrea;Innocenti, Claudia;Sangregorio, Claudio;Lascialfari, Alessandro
2019

Abstract

Recent studies on magnetic nanoparticles (MNPs) used for Magnetic Fluid Hyperthermia treatments have shown that Brownian rotation is suppressed when they are confined within a cell. To investigate this effect we conducted a systematic study of the Specific Absorption Rate (SAR) of colloidal suspensions of MNPs in water and gels at different agarose concentration. SAR measurements were conducted by varying the frequency (f=110–990 kHz) and amplitude (up to 17 kA/m) of the applied alternating magnetic field (AMF). MNP samples with different diameter (d=10, 14, and 18 nm) were used. Our results show that Néel relaxation dominates SAR with negligible contribution from Brownian motion for smaller MNPs (d=10 nm). For the largest MNPs (d=18 nm) we observed a more significant SAR decrease in gel suspensions as compared to those in solution. In particular, when applying AMFs as the ones used in a clinical setting (16.2 kA/m at f=110 kHz), we measured SAR value of 67 W/g in solution and 25 W/g in gel. This experimental finding demonstrates that investigation of MNPs properties should be conducted in media with viscosity similar to the one found in mammalian tissues.
2019
471
504
512
Avolio, Matteo; Guerrini, Andrea; Brero, Francesca; Innocenti, Claudia; Sangregorio, Claudio; Cobianchi, Marco; Mariani, Manuel; Orsini, Francesco; Arosio, Paolo; Lascialfari, Alessandro
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1350696
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