title: Effects of PEO-PPO-PEO triblock copolymers on phospholipid membrane integrity under osmotic stress.
abstract: The effects of PEO-PPO-PEO triblock copolymers, mainly Poloxamer 188, on phospholipid membrane integrity under osmotic gradients were explored using giant unilamellar vesicles (GUVs). Fluorescence leakage assays showed two opposing effects of P188 on the structural integrity of GUVs depending on the duration of their incubation time. A two-state transition mechanism of interaction between the triblock copolymers and the phospholipid membrane is proposed: an adsorption (I) and an insertion (II) state. While the triblock copolymer in state I acts to moderately retard the leakage, their insertion in state II perturbs the lipid packing, thus increasing the membrane permeability. Our results suggest that the biomedical application of PEO-PPO-PEO triblock copolymers, either as cell membrane resealing agents or as accelerators for drug delivery, is directed by the delicate balance between these two states.
authors.affiliation: Department of Chemistry, the Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Jia-Yu
authors.initials: JY
authors.lastname: Wang
authors.forename: Jaemin
authors.initials: J
authors.lastname: Chin
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Marks
authors.forename: Ka Yee C
authors.initials: KY
authors.lastname: Lee
mesh_terms: D008856:Microscopy, Fluorescence; D009995:Osmosis; D010743:Phospholipids / Q000737:chemistry*; D020442:Poloxamer / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry*; D011409:Propylene Glycols / Q000737:chemistry*; D053835:Unilamellar Liposomes / Q000737:chemistry*
chemical_list: C116176:PEO-PPO-PEO; D010743:Phospholipids; D011409:Propylene Glycols; D053835:Unilamellar Liposomes; D020442:Poloxamer; D011092:Polyethylene Glycols