Modelling dynamic changes in tissue stiffness with a reversible azobenzene hydrogel

This thesis develops a new tool to study how cells sense and respond to changes in the stiffness of their surroundings. It creates a safe gel that changes stiffness using visible light instead of harmful ultraviolet light. The research shows that stem cells quickly change their shape and behaviour when the surface they grow on becomes softer or stiffer. Older cells had a slower response, which may explain why healing becomes slower with age. Moreover, this work discovers that cells have a form of memory where they remember previous environment stiffness conditions, and this guides their future behaviour through gene modification. These findings inform strategies to program or reset cellular states for tissue engineering and regenerative medicine.