Novel non-ionic block copolymers tailored for interactions with phospholipids

Abstract

The bulk of literature on phospholipid membrane interactions with non-ionic amphiphilic block copolymers deals with ABA triblock copolymers of poly(ethylene oxide)- b-poly(propylene oxide)- b-poly(ethylene oxide). This is partially the result of their commercial availability. In recent years novel block copolymers have been synthesized and their interactions with phospholipids structured as Langmuir monolayers, liposomes, bilayer lipid membranes, tethered bilayers, and living cells have been studied. This review describes some new block copolymers with potential to interact with phospholipids. There is a tremendous progress in synthesis of amphiphilic block copolymers triggered by new controlled polymerization techniques as atom transfer radical polymerization or nitroxide mediated polymerization and by the possibility to ‘click’ preformed blocks together using quantitative reactions of functional endgroups. A special focus is given to novel water soluble amphiphilic triblock copolymers of poly(glycerol monomethacrylate)- b-poly(propylene oxide)- b-poly(glycerol monomethacrylate) and their interactions with phosphatidylcholine lipids. Also block copolymers containing hydrophobic blocks with perfluoroalkyl groups are discussed since they are special in a sense that their fluorophilic blocks are neither hydrophilic nor oleophilic as this is the case for conventional amphiphilic block copolymers. Experimental methods to study block copolymer–phospholipid interactions are summarized and selected results based on special experimental techniques such as isothermal titration calorimetry, infrared reflection absorption spectroscopy and ion conductance are presented. This work is intended to convey a better quantitative understanding of amphiphilic block copolymers used for in vitro and in vivo experiments in medicine and pharmacy.