Deformation Modes of Giant Unilamellar Vesicles Encapsulating Biopolymers

The shapes of giant unilamellar vesicles (GUVs) enclosing polymer molecules at relatively high concentration, used as a model cytoplasm, significantly differ from those containing only small molecules. Here, we investigated the effects of the molecular weights and concentrations of polymers such as polyethylene glycol (PEG), bovine serum albumin (BSA), and DNA on the morphology of GUVs deflated by osmotic pressure. Although small PEG (MW 10% (w/w), PEG with MW > 6000 induces budding and pearling transformation at above 1% (w/w). Larger PEG frequently induced small buddings and tubulation from the membrane of mother GUVs. A similar trend was observed with BSA, indicating that the effect is irrelevant to the chemical nature of polymers. More surprisingly, long strands of DNA (>105 bp) enclosed in GUVs induced budding transformation at concentrations as low as 0.01–0.1% (w/w). We expect that this molecular size dependency arises mainly from the...