Hybrid nanocomposites with magnetic activation for advanced bone tissue engineering

This chapter deals with recent and innovative approaches in the field of bone tissue regeneration. After a brief introduction on tissue engineering, bone biology and on the traditional strategies currently adopted in the field of bone repair, the chapter focuses on the applications of hybrid magnetic nanocomposite materials in bioengineering and regenerative medicine, as well as on the design, preparation and characterization of three-dimensional (3D) magnetic scaffolds obtained through innovative rapid prototyping technologies such as 3D fiber deposition technique, that offers the fascinating opportunity to develop morphologically-controlled structures with tailored mechanical and mass transport properties. Over the past years, the basic principles of magnetism and magnetic materials have been widely used in many interesting medical applications such as drug and gene delivery, hyperthermia treatment of tumors and radionuclide therapy, magneto-mechanical stimulation or activation of cell-constructs and mechanosensitive ion channels, magnetic cell-seeding procedures and controlled cell proliferation and differentiation. The possibility to extend these concepts to tissue engineering has opened an exciting wide research area of interest. Magnetic scaffolds should be considered as a potential alternative to bone graft substitutes with attractive new performances; they can be manipulated by means of magnetic force gradients in order to attract magnetized cells, increasing scaffold-cell loading efficiency, or bioaggregates (i.e., vascular endothelial growth factor, VEGF), stimulating angiogenesis and bone regeneration, they can also be employed as hyperthermia agents able to deliver thermal energy to targeted bodies (i.e., tumors) or as devices in chemotherapy or radiotherapy. Finally, the possibility to employ magnetic forces for achieving an efficient scaffold fixation is also briefly discussed.