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

Abstract

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 sponge Euplectella 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 enhanced in vitro and in vivo bone-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.

Effect of inositol on the thermally induced crystallization and phase evolution of amorphous calcium phosphate

“…Owing to their different physicochemical properties and accompanying biological characteristics, α-TCP is the major constituent of several kinds of calcium phosphate cements (CPCs) while β-TCP serves in bio-ceramics and composites. [18][19][20] It has been widely accepted that α-TCP is the first crystalline phase obtained by heating ACPs, even though α-TCP was thought to be the high-temperature phase. This phenomenon is explained by the Ostwald step rule, 21 which suggests that the thermodynamically less stable phase can be obtained first during the crystallization process with further transformation to the phase with higher stability.…”

Prestrain Programmable 4D Printing of Nanoceramic Composites with Bioinspired Microstructure

“…The shear force can align anisotropic nanomaterials (e.g., nanosheets, nanofibers) in the ink, leading to microstructured struts with anisotropic functions and great mechanical properties. [29][30][31][32] In this work, the Al 2 O 3 nanosheets were assembled to form the concentric cylinder structure in the nozzle of a circular cross-section during the extrusion process (Figure 1a). Subsequently, the printed lattices were immersed into the CaCl 2 solution so that SA could cross-link and play the role of binder between the nanosheets.…”

“…In addition, regulating the composition ratio, changing the printing speed to manipulate the shear force, and incorporating a third phase are also approaches to control the struts structures. [30][31][32] Herein, we have proposed a facile and versatile method to control the strut microstructures, which can potentially augment the structure controllability of 3D printing and even endow the 3D printed lattices with more outstanding performances (e.g., liquid transportation, negative Poisson's ratio effect, etc.). Despite some progress on printable soft inorganic composites, 3D/4D printed flexible nanoceramicbased composites with extremely high inorganics content have never been reported.…”

3D-Printing for Critical Sized Bone Defects: Current Concepts and Future Directions

“…Kazemi et al investigated a strontium-substituted β-TCP and bioactive glass scaffold seeded with rabbit BMSCs and revealed robust osteoinductive properties and osseointegration into the defect, as evidenced by the lack of a clear border between the remaining scaffold material and new bone [ 103 ]. Additional in vivo studies have investigated the role of scaffolds as treatments for rabbit femoral condyle defects [ 104 , 105 ], as well as 6 mm rabbit and rat femoral shaft defects [ 106 , 107 , 108 ]. The results of these studies indicate that scaffolds generated by robocasting have sufficient biomechanical strength and cell adhesion/proliferation properties to support bone regeneration in weight-bearing limbs but the efficacy of this technique needs to be evaluated in clinically relevant animal models.…”