Additive manufacturing of advanced bioceramics from emulsions based on preceramic polymer

Additive manufacturing (AM) is an emerging technology increasingly used to produce scaffolds composed of bioactive glass and bioceramics. Layer-by-layer deposition of material leads to a high efficiency realization of 3D structures with nanometer precision. Particularly, masked stereolithography technique, with the use of LED light and a LCD screen subdivided into pixel, allows to obtain porous scaffolds with a good resolution and with an unmatched speed. In this specific case this technique has been used to produce porous scaffolds with two differently designed geometries, one corresponding to a gyroid and one to a modified gyroid with holes. The final aim is to manufacture wollastonite-diopside (CaSiO3-CaMg(SiO3)2) bioactive glass-ceramic scaffolds, with chemical, physical and mechanical properties similar to bone tissue, which can be used for personalized repairing of diseased or damaged bone tissue and the stimulation of its own regeneration. For the realization of CaO-MgO-SiO2 composition, it has been used a preceramic silicon polymer (H44) and precursor hydrated salts of magnesium and calcium (Ca(NO3)‧4H2O and Mg(NO3)2⸱6H2O). The salts are nanodispersed in liquid phase in a photosensitive resin by ultrasonic emulsification. This study has the purpose to identify the optimal temperature and atmosphere (air or nitrogen gas) to use for heat-treatment of printed scaffolds, which allows the development of wollastonite-diopside glass-ceramic structures and which, combined with the appropriate geometry, brings to the most suitable physical and mechanical properties of the samples.