Most experiments were carried out at 25 C using premium treated capillaries purchased from NanoTemper Technologies. For some experiments we used custom-treated regular capillaries (NanoTemper Technologies), prepared by cleaning them in the PDC-32G Basic Plasma Cleaner (Harrick Plasma) for 3 minutes followed by silanization in 0.013% dichlorodimethylsilane (Sigma-Aldrich) diluted in trichloroethylene for 30 min. The capillaries were dried by a gentle spin in a tabletop microcentrifuge followed by blotting with kimwipes from one end. After coating with silane, the dried capillaries were treated with 1% Pluronic F-127 solution in MilliQ for 7 min and then dried again by centrifugation and heating at 37 C overnight.