Pluripotency marker Oct4 was still expressed 1 week after 3D bioprinting the iPSCs with iChons in conditioned DEF medium, and the diminishing of Oct4 was seen after chondrogenic differentiation. (A) Western blot of cells before printing in the primary chondrocytes passage 1 before irradiation, in hESCs (human embryonic stem cell line SA121 passage 17), and in chondrocyte-derived iPSC line A2B in DEF xeno- and feeder-free passage 31 or DEF feeder-free culture at passage 17. No expression of pluripotency markers was detected in the chondrocyte cultures. β-Actin was used in the western blot analysis to show equal loading. (B) Immunohistochemistry for Oct4 and nuclei DAPI 1, 4 and 6 weeks after printing the iPSCs with iChons and maintaining the samples in iPSC medium for the first week, followed by the induction of chondrogenic differentiation (the scale bar represents 50 μm).