Enhancement of the pore interconnectivity and porosity of calcium phosphate scaffolds by acid-etching method

Abstract

Porous hydroxyapatite (HA)-tricalcium phosphate (TCP) ceramic scaffolds were prepared using a screw-type extrusion method with polymer beads. HA and dicalcium phosphate dehydrates (DCPD) were added at various ratios to obtain different HA/TCP ratios in sintered ceramic scaffolds. To further enhance the pore interconnectivity and porosity, the developed porous ceramic scaffolds were etched with acid solutions. The maximum porosity (∼85%) was observed in the Ca-P scaffold with the lowest HA (∼7%) content. On the other hand, the maximum compressive strength was noted in the scaffolds with the highest HA content (∼85%). X-ray diffraction showed that the extent of the β-TCP to α-TCP phase transformation increased with decreasing HA/DCPD ratio. All HCl-etched scaffolds were observed to generate micropores, which improved the interconnectivity, while biomineralization was found to be the same for both the HCl-etched and nonetched scaffolds. In particular, hydrochloric acid etching is a promising method for improving the interconnectivity and porosity of the ceramic scaffolds.