Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
11026354 | Journal of Magnetism and Magnetic Materials | 2019 | 18 Pages |
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 (fâ¯=â¯110-990â¯kHz) and amplitude (up to 17â¯kA/m) of the applied alternating magnetic field (AMF). MNP samples with different diameter (dâ¯=â¯10, 14, and 18â¯nm) were used. Our results show that Néel relaxation dominates SAR with negligible contribution from Brownian motion for smaller MNPs (dâ¯=â¯10â¯nm). For the largest MNPs (dâ¯=â¯18â¯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 (16.2â¯kA/m at fâ¯=â¯110â¯kHz), we measured SAR value of 67â¯W/g in solution and 25â¯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.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Matteo Avolio, Andrea Guerrini, Francesca Brero, Claudia Innocenti, Claudio Sangregorio, Marco Cobianchi, Manuel Mariani, Francesco Orsini, Paolo Arosio, Alessandro Lascialfari,