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. (C) 2011 Elsevier B.V. All rights reserved.