Self healing material

This project should represent the process of self-healing material. I would like to have a short animation describing the 4 steps present in the image attached. There should be a material (called hydrogel) and a knife (step 1); this knife should move and create a crack in the hydrogel (step 2). To heal the material, it should be subject to a stimulus (step 3) that allow the material to return to the initial state (step 4)