In-situ fabrication of porous hydroxyapatite (HA) scaffolds with dense shells by freezing HA/camphene slurry

Abstract

We fabricated a novel type of porous HA scaffold with a dense shell/porous core structure by freezing a hydroxyapatite (HA)/camphene slurry in-situ. During freezing, the camphene dendrites from the mold wall grew 2-dimensionally by pushing the HA particles into the remaining slurry, which resulted in the formation of a camphene layer/concentrated HA particles layer as the surrounding skin of the sample. After removing the frozen camphene and sintering the HA walls at 1250 °C for 3 h, a dense shell integrated with a porous core was formed in-situ. We prepared two types of porous HA scaffold, a porous HA cylinder with a dense shell and a 3-D HA scaffold, consisting of periodic HA networks with a dense shell/porous core structure. These novel scaffolds would be expected to have improved mechanical integrity due to the use of a dense shell, as well as efficient bone ingrowth inside pores formed in a porous core.