Highly porous hydroxyapatite scaffolds with elongated pores using stretched polymeric sponges as novel template

This study reports a simple way of improving the compressive strength of highly porous hydroxyapatite (HA) scaffolds by adopting elongated polymeric sponges as a novel template. In this method, as-received polymeric sponges with isotropic pores were stretched uniaxially to 50% elongation at 200 °C for 2 h, and then coated with a HA slurry. The HA-coated sponges were heat-treated at 800 °C for 3 h to remove the polymeric sponges and at 1250 °C for 3 h to sinter the HA walls. The fabricated samples showed a highly anisotropic pore structure with elongated pores parallel to the direction of the elongation of the polymeric sponge. This simple method allowed a highly porous scaffold to have a high compressive strength of 3.8 ± 0.1 MPa at a porosity of 76% when tested parallel to the direction of pore elongation.