The samples of the enhanced Marangoni flow were prepared by depositing droplets of pep1 (5 mM) in acetate buffer (pH 4.8, 25 mM, 0.3 M NaCl) on a parafilm substrate or on a glass slide, underneath a syringe filled with ethanol and capped with a metal needle (0.7 mm diameter). As the volume decreased, the needle was lowered to keep a relatively constant distance from the solution's interface.