To model spatiotemporal CellµEnvs, biosignaling fields can be developed ; using scalar values (e.g. temperature, diffusing chemicals or electric potentials), vectors (e.g. velocities 448 ), and tensors (e.g. mechanical stresses ). As each cells emits and receives signals, their individual contribution can be added or subtracted to the field. For instance, such "sources" and "sinks" can be localized in 3D and signal patterning devices . 3D cultures are influenced by their scaffold's composition 469 , porosity, topography 310 , functionalization, degradation and release of signals . CellµEnv engineering use techniques such as coated beads, soft lithography 471 , gradients 472 , bioprinting 473 , optogenetics and magnetic fields 475 . To grow larger tissues, bioreactors and microfluidic channels help oxygen and nutrients supply, as well as waste and dead cells removal 477 . Finally, mechanical signals can be tuned by materials stiffness and viscoelasticity or using pressure chambers and shear forces . Using these techniques, tissue engineering can control the biosignaling field to regulate organoid long-term cultures 479 . Self-microfabrication benefits from continuous improvements in CellµEnvs characterization, modeling and engineering to support future material-producing organoid development.