Hybrid vesicles resulting from the combined self-assembly of amphiphilic copolymers and phospholipids have attracted particular interest over the last years. Such assemblies may be viewed as advanced vesicular structures compared to their liposomes and polymersomes forerunners as the best from the two systems can be combined (chemical versatility and mechanical stability from polymeric membrane, bio-functionality and permeability from lipidic membrane) and can be used in many applications: nano-reactors for enzymatic reactions, artificial biomimetic cell membrane, etc. Previous works in our group have allowed determining key parameters for the formation of unilamellar hybrid vesicles from micrometric to nanometric sizes (phospholipids fluidity, hydrophobic length mismatch, phospholipids mass fraction, etc.). Triblock copolymer PEO-b-PDMS-b-PEO use until now have however shown some limitations: unexpected mechanical stability of the hybrid vesicles with lysis strains below those of liposomes. This may be due to the architecture of the copolymer which is at the origin of a mix of U-shape (hairpin) or extended chain conformations inside the membrane. To insure a bilayer conformation, in analogy to phospholipid in liposomes, a series of diblock PDMS-b-PEO has been synthesized. The obtained diblock copolymer can form very easily nanosized and microsized polymersomes with tunable membrane thickness and high mechanical stability. Finally, the mixing with phospholipid leads to large hybrid unilamelar vesicles (LHUVs) and giant hybrid unilamelar vesicles (GHUVs). We modulated the copolymer molar mass and the lipid fraction to tune both the membrane structuration (homogeneous membrane, phase separation, budding) and the membrane properties (mechanical strength, fluidity). Finally we obtained vesicles with a high tunability of the membrane properties in order to overcome most of the present limitations in the field of liposomes/polymersomes.

Hybrid polymer/lipid vesicles made from amphiphilic block copolymer poly(dimethylsiloxane)-b-poly(ethylene oxide) as cell-membrane-mimic: Formation, structure, and membrane properties

2019 Spring National Meeting

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