BIOACTIVE GLASS-CERAMIC/MESOPOROUS SILICA COMPOSITE SCAFFOLDS FOR BONE GRAFTING AND DRUG RELEASE

This work is focused on the development of an implantable system coupling bone regeneration and drug release ability. Specifically, ordered mesoporous silica spheres (MCM-41) were loaded onto a bioactive glass-ceramic scaffold. The macroporous scaffolds were prepared using fluoroapatite containing glass-ceramic (Fa-GC) powders and polyethylene (PE) particles of two different sizes. Fa-GC was prepared by a traditional melting-quenching route and was ground and sieved to obtain powders below 30 pm which were mixed with PE particles and then pressed in order to obtain crack-free green samples. The "greens" were thermally treated to remove the organic phase and to sinter the Fa-GC powders. Composite systems were then prepared by soaking the scaffold into the MCM-41 synthesis batch. The samples were characterized through X-Ray Diffraction, morphological observations, density measurements, mechanical tests and in vitro tests. Ibuprofen was used as model drug for uptake and delivery analysis of the system. Composite scaffolds combining the Fa-GC bioactive behaviour with the drug uptake-delivery properties of MCM-41 silica micro/nanospheres were successfully obtained. In comparison with the MCM-41-free scaffold, the adsorption capacity of composite scaffolds was 10 times enhanced and the drug release behaviour was highly affected by MCM-41 mesophase inside the scaffold.