Injectable nano-structured silicon-containing hydroxyapatite microspheres with enhanced osteogenic differentiation and angiogenic factor expression

Abstract Injectable bioactive ceramics with excellent osteogenesis play important roles in bone regeneration field. In this study, we creatively fabricated the injectable nano-structured silicon-containing hydroxyapatite (Si-HAp) microspheres in diameter of 70–100 µm via hydrothermal treatment of calcium silicate (CaSiO 3 ) microspheres in Na 3 PO 4 aqueous solution. The fabricated Si-HAp microspheres were constructed by nano-rods with a diameter of 100 nm and length up to 1.5 µm. Comparing with the pure HAp microspheres, the obtained nano-structured Si-HAp microspheres exhibited excellent protein loading properties and sustained protein release capacities. Most importantly, the Si-substitution could apparently enhance the proliferation, osteogenic differentiation and the genes expression of angiogenic factors of rat bone marrow mesenchymal stem cells (rBMSCs). These all indicated that the nano-structured Si-HAp microspheres fabricated via hydrothermal transformation method might be used as promising injectable bioactive biomaterials and drug deliveries for bone regeneration.