Fig. 15.

4D bioprinting of cartilage tissues.(a–d) DLP of silk-based bilayer bending scaffolds: (a) schematic illustration of the DLP 4D bioprinting process, (b) self-folding process during in vitro culture (scale bars = 1 mm), (c) implantation of the 4D bioprinted cell-laden scaffolds for repairing resected trachea. Reproduced with permission [70]. Copyright 2020, Elsevier B.V. (d–g) 4D bioprinting of bilayer cell-laden scaffolds containing a HAT layer and a AHAT layer: (d) schematic of the 4D bioprinting process using these two inks, (e) Live/Dead images of the cell-laden scaffolds at different time points, (f) schematic and confocal images of the bent cell-laden scaffolds, wherein cells in the top AHAT layer were labeled green and those in the bottom AHAT layer labeled purple, (g) representative hematoxylin-eosin staining images of the scaffolds at different time points during culture. Reproduced with permission [135]. Licensed under a Creative Commons CC BY license.