One-step method to construct hydroxyapatite scaffolds with 3-D interconnected structure by a novel hydrogel bead porogen process

The different pore sizes of hydroxyapatite (HA) scaffolds with an adjustable network of interconnected pores were constructed by a novel one-step alginate hydrogel bead porogen method. Monodisperse alginate hydrogel beads were manufactured by needle-based droplet method with different sizes of needles and pre-treated with organic solvent exchange to enhance mechanical support and deformability. HA slurry was mixed with alginate hydrogel beads followed by physical squeeze for simultaneous construction of three-dimensional scaffold and interconnected windows. The sizes of interconnected windows of HA scaffolds could be adjusted by changing the compressive force of physical squeeze. Finally, the interconnected HA scaffolds were fabricated after sintering the initial blocks. The advantage of the present approach is that the alginate hydrogel beads could shrink during drying the HA scaffolds and release a small amount of gas during sintering, which avoid cracking of cellular structure.