Finally, the cells seeded on top the constructs presented statistically significant higher area compared to the cells within the hydrogels at all timepoints. 3D printed GelMA-Carbopol structures for dynamic tissue modeling. Many organs in the human body, like the heart or lungs, are constantly subjected to cyclic mechanical stress, making 3D printing bioinks that result in stretchable hydrogel structures attractive for dynamic tissue modeling. GelMA-CBP show tunable mechanical properties and excellent stretchability, opening the door to building dynamic tissue biomimetic constructs. To assess GelMA-CBP constructs as mimetics that can undergo cyclic mechanical stress and result in relevant biological cell readouts, we 3D printed dog-bone meshes using 5%GelMA-0.5%CBP-0.5%LAP inks and cultured 3T3 fibroblasts on top of them. A cell and tissue (CaT) stretcher 6 was used to subject the cells to uniaxial stretching for 24 h with cycles between 0 and 20% strain at a frequency of 0.33 Hz (Figure ).