Some variations of the invention provide a bioink composition for 3D bioprinting, comprising: nanocellulose in the form of nanocellulose crystals, nanocellulose fibrils, or preferably a combination thereof； alginate that is ionically crosslinkable in the presence of an ionic crosslinking agent； and water. The nanocellulose-alginate bioinks have favorable rheological, swelling, and biocompatibility properties for extrusion-based bioprinting. It is experimentally demonstrated that nanocellulose-alginate bioinks with human nasoseptal chondrocytes enable cartilage bioprinting at high resolution. The disclosed nanocellulose has been proven to be compatible with cell survival and proliferation； to possess nanoscale and microscale architectures mimicking the native extracellular environment, encouraging differentiation and tissue formation； and to have ideal rheological properties to allow extrusion 3D bioprinting. Bioink with a unique blend of crystal and fibril nanocellulose produces a very stable construct volume in culture.
