“…[51,53,56,61] Developing hydroxyapatite (HA) particles with a magnetic core or doping HA or β-tricalcium phosphate (β-TCP) with transition metal ions has been the most explored approaches to attain CaP-based powders with magnetic properties. [52,57,60,63,139,155,202,[205][206][207][208][209][210][211] By combining the biocompatible and bioactive properties of hydroxyapatite (HA) with the magnetic properties of pure magnetite, it is possible to obtain Fe 3 O 4 /HA core-shell NP of increased therapeutic value and with a greater application potential as a suitable platform for the construction of multifunctional and bimodal magnetic-theranostic carriers, for clinical oncology and novel MRI contrast agents. [57,58,174,177,179,212,213] However, it should be kept in mind that the formed shell may have a thickness greater than the core size, which may result in the decrease of the saturation magnetization of the magnetic material.…”