“Tailored design of multifunctional mesoporous bioactive glasses for bone tissue engineering applications”

Master Thesis in Biomedical Engineering “Tailored design of multifunctional mesoporous bioactive glasses for bone tissue engineering applications” Carla Migneco (DISAT- Politecnico di Torino) Abstract The research in the field of BGs has rapidly evolved in the last decades, reaching excellent performances in terms of biocompatibility and bio-stimulation of regeneration processes. Although many applications based on BGs have been already successfully developed, these materials are still of primary interest not only in applications in contact with hard tissues, but also in soft tissue repair. The BG evolution is also very impressive, evolving from the original melt-derived to the sol-gel BGs. The sol-gel technique further increased the potential of BGs. In fact, bioactive glasses realized by sol-gel synthesis are characterized by higher specific surface area which is directly connected to higher bioactivity performances. Sol-gel technique, coupled with supramolecular self-assembling processes allows the realization of bioactive glasses characterized by a highly ordered mesoporous texture, with pores ranging between 2 and50 nm. The technological potential of MBGs in biomedicine has been recognized to be enormous: their ultrahigh specific surface area, in fact, is able to induce fast reaction rates in biological fluids, leading to an excellent interaction with the biological environment and thus optimizing regenerative effect. One of the most appealing features of MBGs, is the possibility of material functionalization, including drugs or biomolecules loading with specific therapeutic action. Drug delivery is certainly one of the hot topics of actual biomedical research thanks to its enormous potential in patient specific therapies and active targeting. Moreover, the compositional flexibility of BGs can be also exploited for the realization of doped devices that should present additional functions, as antibacterial effects. The present experimental activity deals with the design of mesoporous bioactive glasses based on a complex six-oxide composition in the system SiO2-P2O5-CaO-MgO-Na2O-K2O, named as 47.5B, designed at the Department of Applied Science and Technology of Politecnico di Torino. Previous studies showed that both melt-derived and sol-gel bioactive glasses based on 47.5B system exhibited excellent reactivity in Simulated Body Fluid and an exceptional apatite-forming ability. Here, the design and development of mesoporous bioactive glasses (MBGs) based on the optimization of the composition of 47.5B system was carried out. The role of each precursor in the wet synthesis was deeply investigated in relation to the introduction of the structure directing agent, Pluronic-P123.The obtained sampled have been analysed and characterized using Differential Thermal Analysis (DTA), X-Ray Diffraction and BET analysis. Sol-gel 47.5B system was used as control system for the present study. In addition, a preliminary study on lithium-doped mesoporous bioactive glasses has been carried out, with particular emphasis on the design of a multifunctional biomaterial for the treatment of periodontal diseases, able to induce specific responses at the interface, including osteo-induction, anti-inflammation and cementogenic differentiation.