Fabrication of hydroxyapatite with highly ordered macroporous frame by colloidal templating method

Three-dimensional, highly ordered macroporous frame of hydroxyapatite has been fabricated via a template-assisted colloidal processing technique. In the present method, colloidal template was first prepared with SiO2 spheres by gravitational sedimentation, which was then infiltrated with hydroxyapatite precursor prepared by the sol–gel process. The resulting hydroxyapatite replicated the three-dimensionally ordered macroporous structure of SiO2 template. Modified by H2O2, the SiO2 spheres could be packed into better ordered templates. After removal of the template by immersing in NaOH solution, the well-ordered macroporous frame made from HA was obtained. The arrangement of the pore structure was hexagonal close-packed and pore sizes could be controlled by changing the sizes of SiO2 spheres. The resulting highly ordered macroporous frame of hydroxyapatite could have potential applications in the biomedical field.