Preparation of highly interconnected porous hydroxyapatite scaffolds by chitin gel-casting

In this study, a simple and effective method for producing highly interconnected porous hydroxyapatite (HA) scaffolds was developed by combining gel-casting, particle-leaching and extrusion techniques. Chitin (CT) sol was used to disperse HA particles and wax spheres were introduced as porogens for their excellent deformability. In extrusion process, the accumulated wax spheres in point-to-point contact can transform into surface-to-surface contact by means of the extrusion pressure. Thus, the obtained porous HA scaffolds exhibited an interconnected channel network after leaching out of the porogens. The results showed that the scaffolds prepared by different size of wax spheres exhibited nearly the same volumetric porosity of about 86%, while the compressive strengths decreased as the pore size increased. Therefore, the method developed can be used to effectively tailor the pore size of HA scaffolds while maintaining a high porosity. The highly porous HA scaffolds with excellent interconnectivity are expected to be a promising bone substitute in clinical practice.