To begin with, vesicles containing a calcium chelator EGTA are mixed with an alginate macromer solution. As alginate can be crosslinked in the presence of divalent cations, calcium ions are added to form the hydrogel network. Upon compression of the hydrogel, the vesicles embedded within the hydrogel matrix undergo deformation, increasing membrane tension to form pores and potentially rupture, releasing the internal EGTA. Since EGTA has a much lower dissociation constant (Kd = 1.1 × 10 -7 M) than that of alginate macromers (Kd = 2 × 10 -4 and 1 × 10 -3 M for mannuronic acid and guluronic acid, respectively) for calcium, the released EGTA reversibly and competitively binds to the calcium that crosslinked the hydrogel and ultimately degrades the hydrogel.