Particle-Size Distribution of Dextran- and Carboxydextran-Coated Superparamagnetic Nanoparticles for Magnetic Particle Imaging

During the last few years, nanosized super-paramagnetic materials based on iron-oxide, so called SPIOs, became more and more interesting due to an increasing variety of applications from cancer therapy to contrast enhancement in magnetic resonance imaging. Superparamagnetic iron-oxide based contrast agents like Resovist™ had been widely established in radiological imaging of the reticuloendothelial system. Recently, a novel imaging technique called magnetic particle imaging (MPI) has been proposed for determination of the spatial distribution of iron-oxide nanoparticles. In first publications of MPI, Resovist™ plays a key role. Unfortunately, however, Resovist™ has been withdrawn by Bayer Schering Pharma in the end of 2008. Therefore, the analysis of an acceptable surrogate agent is presented in this paper. By means of dynamical light scattering and magnetic particle spectroscopy it will be demonstrated that dextrancoated iron oxide nanoparticles can be synthesized with similar particle size distribution and analogous magnetic properties compared to the carboxydextran-coated Resovist™.