Porous hydroxyapatite scaffolds fabricated from nano-sized powder via honeycomb extrusion

In this study, we have developed hydroxyapatite (HA) scaffolds for synthetic bone graft from nano-sized HA particles using ceramic extrusion. We also demonstrate that these HA scaffolds show enhanced compressive strength (29.4 MPa), whilst possessing large pore sizes (> 600 µm) that are suitable for bone grafting. The extrusion process involved forming a ceramic paste by mixing the HA powder with a binder and distilled water. The ceramic paste was then fabricated using a ram extruder that was fitted with a honeycomb die to impart large, structured pores. Several green bodies were extruded and then subjected to the same drying and thermal debinding treatment. The samples underwent three different sintering temperatures and two varied dwell times, in order to determine the optimum sintering parameters. The scaffolds were then analysed for their chemical, physical, mechanical and biological properties to elucidate the effects of the sintering parameters on extruded HA scaffolds. The resul