Biofabrication of engineered tissues by 3D bioprinting of tissue specific high cell-density bioinks.

Bioprinting of high cell-density bioinks is a promising technique for cellular condensation-based tissue engineering and regeneration medicine. However, it is still difficult to create precisely controlled complex structures and organization of tissues with high cell-density bioink-based bioprinting for tissue specific condensation. In this study, we present newly biofabricated tissues from directly assembled, tissue specific, high cell-density bioinks which have been three-dimensionally printed into a photocrosslinkable and biodegradable hydrogel microparticle supporting bath. Three types of tissue specific high cell-density bioinks have been prepared with individual stem cells or stem cell aggregates by incorporation of growth factor-loaded gelatin microparticles. The bioprinted tissue specific high cell-density bioinks in the photocrosslinked microgel supporting bath condense together and differentiate down tissue-specific lineages to form multi-phase tissues (e.g., osteochondral tissues). By changing the growth factors and cell types, these tissue specific high cell-density bioinks enable engineering of various functional tissues with controlled architecture and organization of cells.