Fig.9 Characteristic of biomimicking trilayer scaffolds containing a 3D bioprinted BMSC-laden hydrogel layer. (A) An optical image of 3D printed GelMA/Gel hydrogel. (B) Optical images and (C) fluorescence images of 3D bioprinted BMSC-laden hydrogel. (D) Live/dead assay results of BMSCs in trilayer scaffolds after culturing for 1, 3 and 7 days. (E) Cell survival rates of BMSCs in trilayer scaffolds after culturing for 1, 3 and 7 days. (F) Shape morphing of a trilayer scaffold from the planar shape to tubular structure when cultured at 37 ℃. (The red layer in the scaffold was the 3D bioprinted BMSC-laden hydrogel layer.) (G) CLSM images showing the 3D distribution of BMSCs in trilayer scaffolds after scaffold shape morphing at 37 ℃.