Support-less 3D bioceramic/extracellular matrix printing in sanitizer-based hydrogel for bone tissue engineering

Abstract To meet the growing demand for bone scaffolds, 3D printing has made significant advancements in bone tissue engineering. However, the materials used must closely mimic the biological components and structural characteristics of natural bone tissue. Additionally, constructing complex, oblique structures presents significant challenges. To address these issues, we explored 3D bioceramic printing using a sanitizer-based hydrogel. Collagen, a major component of the bone extracellular matrix (ECM), was combined with alpha-tricalcium phosphate (α-TCP) to create the bioceramic ink. The sanitizer-based hydrogel was chosen as the gel bath because it contains Carbopol, which provides hydrogel-like support, and ethanol, which coagulates collagen and preserves the 3D-printed structure. The α-TCP/collagen bioceramic ink was printed in the sanitizer-based hydrogel, then collected, washed in ethanol, and finally submerged in phosphate buffer saline (PBS) to initiate a self-setting reaction, transforming α-TCP into calcium-deficient hydroxyapatite (CDHA). The results demonstrated that complex ceramic/ECM structures could be printed in the sanitizer bath and exhibited excellent mechanical characteristics. Furthermore, scaffolds printed with a sanitizer bath showed higher levels of cell growth and osteogenic activity compared to scaffolds produced with only α-TCP in an open-air environment. This proposed bioceramic printing approach has the potential to construct complex scaffolds with strong osteogenic potential for bone regeneration.