Fabrication and characterization of bioactive calcium silicate microspheres for drug delivery

The calcium silicate (CaSiO3, CS) microspheres with diameter of 75–100 μm were fabricated by a spray-drying method. A new bone-like apatite layer fully covered the surface of the fabricated CS microspheres after soaking in simulated body fluid (SBF), suggesting the excellent activity of the material in inducing apatite deposition. The ionic extracts of CS microspheres promoted the proliferation of human osteoblast-like cells (MC3T3-E1). In addition, the porous structures of the CS microspheres resulted in favorable drug loading and sustained release property. Our study indicates that the fabricated multifunctional CS microspheres are a promising drug delivery system as an injectable bioactive filling material for bone-regeneration.