Magnetic Nanoparticles Adapted for Specific Biomedical Applications

Magnetic nanoparticles are used in different biomedical applications, whereby each application requires specific particle properties. To fulfil these requirements, particle properties have to be optimized by means of variation of crystal structure, particle size, and size distribution. To this aim, improved aqueous precipitation procedures for magnetic iron oxide nanoparticle synthesis were developed. One procedure focused on cyclic growth of magnetic nanoparticles without nucleation of new particle cores during precipitation. The second novel particle type are magnetic multicore nanoparticles, which consist of single cores of about 10 nm forming dense clusters in the size range from 40 to 80 nm. Their highest potential features these multicore particles in hyperthermia application. In our in-vivo experiments, therapeutically suitable temperatures were reached after 20 seconds of heating for a particle concentration in tumor of 1 % and field parameters of H = 24 kA/m and f = 410 kHz. This review on our recent investigations for particle optimization demonstrates that tuning magnetic properties of magnetic nanoparticles can be obtained by alteration of their structure, size, and size distribution. This can be realized by means of control of particle size during synthesis or subsequent size dependent fractionation. Here developed particles show high potential for biomedical applications.