Supplementary Figure 1.

HAc-Alg/CaP scaffold directly printed on a glass slide. Left: one layered structure of the scaffold, Right: three-layered structure of the scaffold. During 3d printing, the HAc-Alg ink with (NH4)2HPO4 was deposited on the surface of a glass slide, followed by UV crosslinking. The printed scaffolds were treated in CaCl2 solution for physical crosslinking of alginate and mineralization. The one-layer scaffold could maintain its meshed structure. However, for a scaffold with multi-layered structure, the top layers were collapsed during printing, being merged with the bottom layers.