Cubic anisotropic Co and Zn substituted ferrite nanoparticles as multimodal magnetic agents

The use of magnetic nanoparticles as theranostic agents for the detection and treatment of cancer diseases has been extensively analyzed in the last few years. In this work, cubic-shape cobalt and zinc-doped iron oxide nanoparticles with edge lengths in the range from 28 to 94 nm are proposed as negative contrast agents for magnetic resonance imaging and to generate localized heat by magnetic hyperthermia, obtaining high values of transverse relaxation coefficients and specific adsorption rates. The applied magnetic fields presented the suitable characteristics for the potential validation of the results into the clinical practice in all cases. Pure iron oxide and cobalt and zinc substituted ferrites have been structural and magnetically characterized, observing magnetite as the predominant phase and weak ferrimagnetic behavior at room temperature, with saturation values even larger than those of bulk magnetite. The coercive force increased due to the incorporation of cobalt ions while zinc substitution p...