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

To meet the increasing demand for bone scaffolds, advancements in 3D printing have significantly impacted 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 considerable challenges. To address these issues, we explored 3D bioceramic printing using a sanitizer-based hydrogel. Collagen, a primary component of the bone extracellular matrix (ECM), was combined with alpha-tricalcium phosphate (alpha-TCP) to create the bioceramic ink. The sanitizer-based hydrogel was chosen as the gel bath due to its carbopol content, which provides hydrogel-like support, and ethanol, which coagulates collagen and maintains the integrity of the 3D-printed structure. The alpha-TCP/collagen bioceramic ink was printed within the sanitizer-based hydrogel, then collected, immersed in ethanol, and finally submerged in phosphate-buffer saline to initiate a self-setting reaction that converted alpha-TCP into calcium-deficient hydroxyapatite. The results demonstrated that complex ceramic/ECM structures could be successfully printed in the sanitizer bath, exhibiting excellent mechanical characteristics. Additionally, scaffolds printed in the sanitizer bath showed higher levels of cell growth and osteogenic activity compared to those produced with only alpha-TCP in an open-air environment. This bioceramic printing approach has a strong potential for constructing complex scaffolds with enhanced osteogenic potential for bone regeneration.