“…Hydrogels have several uses for tissue engineering. They can be used as a soft 3D ECM‐like environment, [ 115 , 119 , 226 , 227 , 228 , 229 , 230 , 231 , 232 , 233 , 234 , 235 , 236 , 237 , 238 , 239 ] as a 3D matrix filler inside porous scaffolds, [ 240 ] as components of bioinks, [ 34 , 121 , 187 , 222 , 241 , 242 , 243 , 244 , 245 , 246 ] as thin membranes which may be microstructured to produce alignment of cells, [ 126 , 247 ] or as source material to develop porous scaffolds. [ 23 , 248 , 249 ] For the first three uses, cytocompatible gelation is essential, as the cells are introduced into the hydrogel liquid solution before the hydrogel solidifies.…”