Magnetic Colloidal Fluids: Dynamics and Applications
Vortragender: Prof. Dr. Rolf Hempelmann, Physikalische Chemie, Universität des SaarlandesMo. 19.05.2008 (16:00-17:00), H 16, NW II
Ferrite nanoparticles with sphere-like or rod-like shapes are prepared by wet chemical methods. For electrostatical stabilization they can be covered with silica shells. Rod-like nanoparticles with variable aspect ratio, due the strong effect of their magnetic form anisotropy, can easily be aligned in magnetic fields as shown by SAXS. Via depolarized light scattering experiments the rotational diffusion is investigated. Due to superparamagnetic relaxation, magnetic nanoparticles absorb energy from radiofrequency fields; for the system Mn1-xZnxFe2O4 from corresponding heating curves the Curie temperatures have been deduced. Due to ferromagnetic resonance magnetic nanoparticles absorb energy from microwave fields; for dispersions in adhesives this effect can be utilized for bond-on-command applications. For application in biological organisms, these magnetic nanoparticles have been functionalised with the polysaccharide dextran. As a model chemotherapeutic drug doxorubicin, due to its auto fluorescence, has subsequently been bonded to the particles. The uptake efficiency of the modified ferrite particles into T lymphocytes was verified by fluorescence and confocal microscopy. Work on the dynamic magnetic drug release is in progress now.
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