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Her Topic of Materials' Days 2010:
Magnetic nanoparticles for biomedical applications
The development and application of modern magnetic materials requires a basic
understanding of the magnetization processes that determine the magnetic properties. This
can be obtained through preparation of novel magnetic systems, complex characterization
methods and simulations.
Nanostructured magnetic systems are playing a great role in material science nowadays
because of the large range of possible applications. Magnetic nanoparticles commonly used
in medicine are in the size range from several to hundreds of nanometers. The only
possibility to see and be able to predict the behavior of a single particle is through
Magnetic nanoparticles offer attractive possibilities as contrast agents because of the Néel –
relaxation. The particles show resonance behavior in a time - varying magnetic field. The
MRI relies on the counterbalances between the small magnetic moment of a hydrogen
proton and the extremely large number of hydrogen atoms in biological tissue. The presence
of magnetic nanoparticles in biological tissue influences the relaxation times. The contrast
enhancement due to the magnetic particles is related to the fact that we are shortening the
relaxation time T2.
Another attractive application is the magnetic cancer hyperthermia treatment. The potential
of hyperthermia and thermal ablation in cancer therapy has been well noted. Temperatures
between 42°C and 46°C lead to inactivation of norma l cellular processes, whereas above
46°C, extensive necrosis occurs. The inability to d eposit effective doses of heat in a tumor
without applying similar heat on surrounding tissues has prevented widespread clinical use.
Magnetic nanoparticles responding to alternating magnetic fields provide a novel approach
for the direct thermal ablation of tumor cells.