All chemicals were from Sigma-Aldrich. Samples were prepared as indicated in the main text and as follows: we first dispersed PEG (20 kDa at 2.5, 5 and 10%) in 1-octanol by heating and shaking samples at 80°C to fully solubilize the polymer. PVA (Mowiol 4-88, 31 kDa, ref 31381) was weighted and water was added to get a 10% concentration, this stock solution was further heated at 70°C for 1H and shaken overnight with a magnetic stirrer. Both bPEI 14% and PVPone 10% were also weighted, hydrated with pure water and shaken overnight with a magnetic stirrer, without heating solutions.