Synthesis and characterization of SiO2–CaO–P2O5 hollow nanospheres for biomedical applications

A ternary system of SiO2–CaO–P2O5 hollow nanospheres has been successfully prepared by sol–gel method using polystyrene (PS) nanospheres as template. The inorganic shell was produced using tetraorthosilicate (TEOS) as the silica source and tri-calciumphospate as calcium and phosphorus sources, respectively. The positive surface charge of the template and the [template]/[TEOS] ratio were the key parameters for the creation of a stable primary inorganic network and the further growth of the shell. The removal of the polymeric core through a thermal treatment procedure created an inner void space with mean diameter 250 nm while the outer mean diameter was 330 nm.

► Fine hollow SiO2-CaO-P2O5 nanospheres via core-shell synthesis.
► Structure stability was observed even though the layer was very thin.
► Nanospheres with thinner layer showed transparent at the SEM micrographs.