Formation of defined SPIO clusters by continuous flow encapsulation

Superparamagnetic iron oxide nanoparticles (SPIO) can be used to form contrast agents with improved sensitivity and specificity. Their magnetic read-out in MRI or MPI measurements avoids risks which occur from ionizing (CT) or radioactive (PET) radiation. To study the effects of size, shape and surface modifications the used SPIOs have to be monodispers with well defined and reproducible properties. These particles are typically produced by thermal decomposition with diameters only between 5 and 20 nm and only dispersible in non polar solvents. Nanoparticles with larger diameters for improved signal to noise ratio (SNR) lose their superparamagnetic behavior while those produced in water show a lack in crystallinity and monodispersity.