Nature of interactions between PEO-PPO-PEO triblock copolymers and lipid membranes: (I) effect of polymer hydrophobicity on its ability to protect liposomes from peroxidation.
PEO-PPO-PEO triblock copolymers have opposing effects on lipid membrane integrity: they can behave either as membrane sealants or as membrane permeabilizers. To gain insights into their biomembrane activities, the fundamental interactions between a series of PEO-based polymers and phospholipid vesicles were investigated. Specifically, the effect of copolymer hydrophobicity on its ability to prevent liposomes from peroxidation was evaluated, and partitioning free energy and coefficient involved in the interactions were derived. Our results show that the high degree of hydrophilicity is a key feature of the copolymers that can effectively protect liposomes from peroxidation and the protective effect of the copolymers stems from their adsorption at the membrane surface without penetrating into the bilayer core. The origin of this protective effect induced by polymer absorption is attributed to the retardation of membrane hydration dynamics, which is further illustrated in the accompanying study on dynamic nuclear polarization (DNP)-derived hydration dynamics (Cheng, C.-Y.; Wang, J.-Y.; Kausik, R.; Lee, K. Y. C.; Han S. Biomacromolecules, 2012, DOI: 10.1021/bm300848c).
Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute, University of Chicago, Illinois 60637, USA.
Jia-Yu
JY
Wang
Jeremy
J
Marks
Ka Yee C
KY
Lee
D000327:Adsorption; D000578:Amidines / Q000737:chemistry; D001672:Biocompatible Materials; D002151:Calorimetry; D057927:Hydrophobic and Hydrophilic Interactions; D008027:Light; D015227:Lipid Peroxidation; D008081:Liposomes / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011409:Propylene Glycols / Q000737:chemistry*; D012542:Scattering, Radiation; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D000578:Amidines; D001672:Biocompatible Materials; D008081:Liposomes; C116176:PEO-PPO-PEO; D010743:Phospholipids; D011409:Propylene Glycols; D013501:Surface-Active Agents; D014867:Water; D011092:Polyethylene Glycols; C046728:2,2'-azobis(2-amidinopropane)