Tunable iron-based contrast agent for efficient Magnetic Fluid Hyperthermia in Magnetic Resonance Imaging and Magnetic Particle Imaging

In recent years our research group has focused on the study of the biomedical applications of magnetic nanoparticles for therapy and diagnosis (theranostics) of tumor pathologies on animal models. Considering diagnostics, the tomographic and molecular imaging techniques able to detect small quantities of iron (an essential component of magnetic nanoparticles used for biomedical purposes) during in vitro and in vivo experiments were of great interest to the group. For these purposes the techniques mainly used were Nuclear Magnetic Resonance (MRI) and Magnetic Particle Imaging (MPI), able to provide a high morphological tomographic resolution (MRI) and the ability to observe small quantities of iron both in vitro on cells and in vivo on murine models. Considering therapy, magnetic nanoparticles able to produce magnetic hyperthermia were mostly studied. Magnetic hyperthermia is a term used for the generation of heat by nanoparticles once subjected to the application of alternating external magnetic fields. Specifically, one of the main research interests of the group in the last four years was to study, characterize and apply, in breast cancer models (MDA-MB-231 and 4T1) both in vitro and in vivo, nanoparticles with a peculiar magnetic phase transition. These particles have proved able to undergo a magnetic phase transition as a function of the temperature variation, after applying external alternating magnetic fields. In this way it was possible to alter their ability to generate heat. This class of nanoparticles has demonstrated to be an important turning point in the panorama of magnetic hyperthermia in the preclinical field, as they were able to self-regulate the temperature variation produced by the application of external alternating magnetic fields thus preventing the possibility of damaging healthy tissues in the immediate surrounding of the pathological tissues. A wide variety of investigation techniques was adopted to characterize the nanoparticles used for experimental purposes. In particular, techniques such as infrared spectroscopy, X-Ray powder diffraction, dynamic light scattering and transmission electron microscopy have made it possible to understand the physico-chemical nature of the hyperthermia mediators used in the subsequent experimental phase. The application of hyperthermia for in vitro and in vivo experimentation was then observed by means of MRI and MPI investigations subsequently compared with the histological results obtained from the staining of the tissues involved in the studies (typically tumor tissues and the main organs involved in the bioaccumulation of nanoparticles such as the liver, kidneys and spleen). Overall, the in vitro and in vivo results were as relevant as being the subject of a scientific publication and a further future publication currently being finalized, confirming the concrete possibility of their future application in the biomedical clinical field.