Theoretical studies to elucidate the influence of magnetic dipolar interactions occurring in the magnetic nanoparticle systems, for biomedical applications

International Conference on Applied Sciences 2015

Osaci, M.^1 ; Cacciola, M.^2

Politehnica University of Timisoara, Department of Electrical Engineering and Industrial Informatics, Vasile Parvan str., no. 1-2, Timisoara

300223, Romania^1

University Mediterranea of Reggio Calabria, DICEAM, Via Graziella Feo di Vito, I-89100, Italy^2

关键词: Biomedical applications;    External magnetic field;    Magnetic dipolar interactions;    Magnetic moment orientations;    Nanoparticle concentrations;    Orientational distributions;    Spherical nanoparticles;    Technological applications;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/106/1/012004/pdf
DOI  :  10.1088/1757-899X/106/1/012004

来源: IOP

【 摘 要 】

In recent years, the study of magnetic nanoparticles has been intensively developed not only for their fundamental theoretical interest, but also for their many technological applications, especially biomedical applications, ranging from contrast agents for magnetic resonance imaging to the deterioration of cancer cells via hyperthermia treatment. The theoretical and experimental research has shown until now that the magnetic dipolar interactions between nanoparticles can have a significant influence on the magnetic behaviour of the system. But, this influence is not well understood. It is clear that the magnetic dipolar interaction intensity is correlated with the nanoparticle concentration, volume fraction and magnetic moment orientations. In this paper, we try to understand the influence of magnetic dipolar interactions on the behaviour of magnetic nanoparticle systems, for biomedical applications. For the model, we considered spherical nanoparticles with uniaxial anisotropy and lognormal distribution of the sizes. The model involves a simulation stage of the spatial distribution and orientation of the nanoparticles and their easy axes of magnetic anisotropy, and an evaluation stage of the Néel relaxation time. To assess the Néel relaxation time, we are going to discretise and adapt, to the local magnetic field, the Coffey analytical solution for the equation Fokker-Planck describing the dynamics of magnetic moments of nanoparticles in oblique external magnetic field. There are three fundamental aspects of interest in our studies on the magnetic nanoparticles: their spatial & orientational distributions, concentrations and sizes.