While delivering genes by chemical methods, one popular conjecture about what happens to poly(ethylenimine)/DNA complexes following endocytosis is known as the proton sponge hypothesis, which entails the following steps

(A). PEI/DNA complexes are endocytosed.

(B). V-ATPases will pump protons into the vesicular interior

(C). Water will enter the vesicle to balance the osmotic gradient

(D). The vesicle will swell due to the entry of ions and water, leading to rupture