Preparation and in vitro apatite-forming ability of porous and non-porous titania microspheres

Abstract

Porous and non-porous titania microspheres with the anatase or rutile phase were successively prepared by the sol-gel process followed by heat treatment at various temperatures. The pore size of the prepared microspheres was effectively controlled by incorporating silica nanoparticles of different diameters. The apatite-forming ability of the microspheres was investigated in a simulated body fluid, with ion concentrations nearly equal to those of human blood plasma. Results indicated that the titania microspheres with either anatase or rutile structure induced the formation of calcium phosphate compounds (CaPs) on the microsphere surface. The deposition of CaPs was more pronounced on the TiO2 microspheres calcined at 600°C (anatase structure) and 800°C (rutile structure), compared to that calcined at 500°C (anatase structure). Additionally, anatase micro-spheres with smooth surface and low specific surface area favored the formation of CaPs, compared to porous microspheres. This indicates that nanoscale pores do not essentially favor apatite formation. © 2013 The Ceramic Society of Japan. All rights reserved.