Production of highly porous triphasic calcium phosphate scaffolds with excellent in vitro bioactivity using vacuum-assisted foaming of ceramic suspension (VFC) technique

We produced highly porous triphasic calcium phosphate (CaP) scaffolds, comprising of hydroxyapatite (HA), β-tricalcium phosphate (β-TCP), and α-TCP phases, using vacuum-assisted foaming of a ceramic suspension (VFC) technique. In particular, vigorously foamed CaP green bodies with a composition of ∼60 wt% HA and 40 wt% β-TCP were sintered at relatively high temperatures (1200, 1250, 1300, and 1350 °C) to control the amount of three constituent phases. All the produced samples showed a highly porous structure (porosity ∼ 83.5–84.5 vol%, pore size ∼ 312–338 μm, and interconnection size ∼ 61–74 μm) with a number of microchannels in the CaP walls. However, sintering at relatively high temperatures≥1250 °C induced considerable phase transformation of the β-TCP to α-TCP phases. The presence of the more soluble α-TCP phase in the triphasic CaP scaffolds significantly enhanced the in vitro bioactivity of the porous CaP scaffolds, which was assessed in terms of their apatite-forming ability in simulated body fluid (SBF).