Development of Bioinspired Biphasic Calcium Phosphate Inks for Manufacturing Bone Scaffolds by Robocasting

Robocasting calcium phosphate compounds as a novel approach to creating customized structures with interconnected pores not only overcomes the limitations of traditional fabrication methods of calcium phosphate substitutes but also boosts the potential for bone tissue regeneration. The ink development is a key step in 3D printing. In this study, different inks consisting of magnesium- and sodium-doped carbonated hydroxyapatite, β-tricalcium phosphate, and Pluronic F-127 were prepared to design biomimetic bone scaffolds. To achieve suitable printability and subsequently, structures with high shape fidelity and appropriate mechanical properties, the selected compositions were evaluated by rheological analysis and mechanical tests. The results demonstrated that the prepared inks exhibited shear thinning behavior, and by increasing the concentration of Pluronic and biphasic calcium phosphate (BCP), more consistent gels were obtained that were able to maintain their shape after printing. The compressive strength of the scaffolds varied in the range of ∼8-60 MPa. The morphology of the sintered scaffolds in the scanning electron microscopy images also showed a dual macro- and micropore-size architecture, which can promote the adhesion of proteins and cell behavior. Our findings indicated that bioinspired BCP scaffolds can be fabricated with relatively high precision for use as cancellous bone substitutes.