A new approach to fabricate bioactive silica binary and ternary hybrid microspheres

Bioactive microspheres represent an extremely developing field in biomedical applications, such as bone tissue engineering and bone pathologies (metabolic bone disease, trauma or bone cancer). Their innate osteogenic properties have turned them to biomaterials with improved added value. The aim of this study was to prepare binary and ternary hybrid silica microspheres with enhanced bioactive properties according to our previous synthetic procedure. In brief, the synthetic approach based on the emulsifier free-emulsion polymerization method, by which polystyrene (PS) microspheres were produced and used as core template for the sol-gel coating method. During the coating reaction an inorganic shell was fabricated by silane and phosphate precursors (tetraethoxysilane, trimethylphosphate). The final microspheres were treated by different catalyst concentrations, during the coating process, which resulted in the formation of diffused voids (a porous-like structure). The in vitro bioactivity of the resultant microspheres was studied by treatment in simulated body fluids (SBF). The bioassay evaluation indicates the deposition of a bone-like apatite layer on microspheres' surface with enhanced bioresorbability, which verifies their bioactivity and permits their application in the treatment of bone pathologies.