3D printing of sponge spicules-inspired flexible bioceramic-based scaffolds

Bioceramics are widely used in bone tissue repair and regeneration due to their desirable biocompatibility and bioactivity. However, the brittleness of bioceramics results in difficulty of surgical operation, which greatly limits their clinical applications. The spicules of the marine spongeEuplectella aspergillum(Ea) possess high flexibility and fracture toughness resulting from concentric layered silica glued by a thin organic layer. Inspired by the unique properties of sponge spicules, flexible bioceramic-based scaffolds with spicule-like concentric layered biomimetic microstructures were constructed by combining two-dimensional (2D) bioceramics and 3D printing. 2D bioceramics could be assembled and aligned by modulating the shear force field in the direct ink writing (DIW) of 3D printing. The prepared spicules-inspired flexible bioceramic-based (SFB) scaffolds differentiated themselves from traditional 3D-printed irregular particles-based bioceramic-based scaffolds as they could be adaptably compressed, cut, folded, rolled and twisted without the occurrence of fracture, significantly breaking through the bottleneck of inherent brittleness of traditional bioceramic scaffolds. In addition, SFB scaffolds showed significantly enhancedin vitroandin vivobone-forming bioactivity as compared to conventional β-tricalcium phosphate (β-TCP) scaffolds, suggesting that SFB scaffolds combined both of excellent mechanical and bioactive characteristics, which is believed to greatly promote the bioceramic science and their clinical applications.