INVESTIGADORES
MENDOZA ZELIS Pedro
congresos y reuniones científicas
Título:
The physics behind magnetic hyperthermia
Autor/es:
M. B. FERNÁNDEZ VAN RAAP; F. H. SÁNCHEZ; G. A. PASQUEVICH; P. MENDOZA ZÉLIS; S. STEWART; M. E. DE SOUSA; I. J. BRUVERA; C. LABORDE; P. GIRARDIN
Lugar:
La Plata
Reunión:
Conferencia; HK 2010 - Humboldt Kolleg; 2011
Institución organizadora:
Physics Department - Faculty of Exact Sciences National University of La Plata
Resumen:
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Magnetic
nanoparticles (MNP) are multifunctional objects which show growing
interest in biomedical applications for both diagnosis and therapy.
Due to their nanometric size they can interact with living cells and
can be internalized. The MNPs locate in intracellular membrane bound
vesicles known as endosomes. Localization at the nanoscale is clearly
seen by electron microscopy. Once internalized, the functionality of
these magnetic agents is exported into the cells. The MNP magnetic
moment acts as a mediator and allows non invasive long distance
manipulation.In
fact, they are used as agents for various strategies like:
enhancement in magnetic resonant imaging, selective cell separation,
drug delivery and local heat dissipation. In
the latter, named magnetic hyperthermia, temperature increase is
achieved when the MNP is subjected to an alternating magnetic field
in the radio frequency range. The heating power is governed by the
mechanisms of magnetic energy dissipation for single-domain particles
(Brown and Néel relaxations) and is highly sensitive to MNP
properties like size, magnetic anisotropy, and saturation
magnetization; to solvent viscosity, and to the magnetic field
frequency f and amplitude H0. The
MNP power lost can be improved increasing both f and H0,
but this rise is limited by physiological issues i.e there is a
maximum value of the product f H0 to
which human bodies can be exposed without discomfort. MNP are
subjected to other restrictions aside to biocompatibility and
toxicity. Even local hyperthermia offers numerous advantages as a
novel cancer therapy; however, it requires for small tumours a
remarkably high heating power of more than 1 kWg−1 for
heat agents. In
the present talk the current state of knowledge in nanoparticle
properties, their internalization and magnetic intracellular
hyperthermia in discussed.