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.
|Titolo:||In-gel study of the effect of magnetic nanoparticles immobilization on their heating efficiency for application in Magnetic Fluid Hyperthermia|
|Parole Chiave:||Magnetic Fluid Hyperthermia; Magnetic nanoparticles; Superparamagnetism; Specific Absorption Rate; Relaxation times; Brownian motion|
|Settore Scientifico Disciplinare:||Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)|
|Data di pubblicazione:||2018|
|Digital Object Identifier (DOI):||10.1016/j.jmmm.2018.09.111|
|Appare nelle tipologie:||01 - Articolo su periodico|