(A) ζ-potential of GUVs and GUVs incubated with P181, P407, P338 and P188 for less than 3 hours. (B) Time-lapse of leakage of Alexa 488, measured as a decrease in the relative fluorescence intensity, I/I0, upon perfusion of P188, P338, P407 and P181 at Δπ = 23 ±2 mOsm.