Cost-effective 3D printing of whey-hydroxyapatite composites for the fabrication of biocarbon-ceramic bone scaffolds with hierarchical porosity

Composite bone scaffolds made of carbonised whey and hydroxyapatite (HA) are presented. The rheological properties of the whey-HA pastes make them suitable for Direct-Ink-Writing (DIW). High-quality printed whey-HA scaffolds with interconnected channels ranging from 100 to 250 μm have been achieved. Through carbonisation, whey acts as a thermoset resin, thus preserving the original shape of the scaffold and resulting in a porous biocarbon with pore sizes from micrometres to nanometres. The carbon phase confers the scaffolds with adequate mechanical properties, attaining compression strength values of 10–14 MPa. The obtained materials exhibit greater bioactivity than a reference scaffold of sintered HA. Biological tests indicate that these materials are biocompatible and promote cell adhesion. The additive manufacturing of biocarbon-HA composites presented here implies a notable improvement in terms of cost-effectiveness, as it reduces the amount of expensive materials required in combination with considerably simpler and less energy-intensive manufacturing processes.