There is a need to recapitulate the native complexity of bone structure within engineered 3D structures with tailored biological and mechanical properties. In this study, we suggest an innovative cell-printing process, supplemented with core/shell nozzle and co-cultured/mono-cultured methods, to achieve 3D osteon-like structures through cell-laden bioinks using an extrusion-based 3D bioprinter in one-step. In this study, vascularization promoting and osteogenic bioinks were developed based on different concentration of GelMA-alginate hydrogels with the incorporation of hydroxyapatite nanoparticles. These hydrogels were chosen due to their suitable mechanical stability, swelling ratio, and printability. To obtain a core/shell osteon-like structure (CSBP), we used a vascularization bioink combined HUVECs in the core region, and used osteogenic- MC3T3-E1 cells-laden bioinks in the shell region. Pure gelatin was concentration in all bioinks to support both of core and shell structures during 3D bioprinting. Coreco-cultured osteon-like structure (CCBP) was fabricated through co-culturing of HUVECs and MC3T3 cells within bioink in the core region.
