Figure 3.

Schematic diagram and typical experimental results of (a) material extrusion-based freeform 3D printing (adapted with permission from Wu et al. ³⁴ ), (b) cell-laden ink extrusion-based freeform 3D printing (adapted with permission from Noor et al. ⁷⁷ ), (c) cell construct-based freeform 3D printing (adapted with permission from Norotte et al. ⁸⁰ ), (d) photodegradation-based freeform 3D printing (adapted with permission from Arakawa et al. ⁸⁵ ), and (e) projection stereolithography-based freeform 3D printing (adapted with permission from Thomas et al. ⁸⁸ ).