Bone Tissue Regeneration Monitoring Using Magnetic Scaffold via Microwave Imaging: a feasibility assesment

Magnetic scaffolds (MagS) are the combination of traditional biomaterials (e.g., polymers, bioceramics, bioglasses) and magnetic nanoparticles (MNPs) [1]. MagS are multifunctional devices that can be controlled, in a remote and noninvasive way, by an external static or dynamic electromagnetic (EM) field. Among possible applications of MagS we can mention hyperthermia of deep-seated tumors, or enhanced drug delivery, as well as alternative diagnostic approaches. Also, MagS can play a disruptive role in tissue engineering (TE), enabling the magnetic guidance of tissue repair by using very low frequency $(1-100 \mathrm{~Hz})$ or pulsed EM fields. However, MagS are mostly developed as bone substitutes for TE applications [1], [2]. Even though MagS are intrinsically a theranostic tool, their potential is highly underestimated. In particular, limited efforts have been spent to assess monitoring capabilities of MagS for the follow up of bone tissue regeneration. A preliminary analysis on the signal level variations that can be observed during hyperthermia treatments and during bone regeneration are reported in [3] and [4], respectively. Therein, a 1D model based on the transmission line formalism and initial guideline to design a monitoring device were provided.