Magneto‐Thermal Release from Nanoscale Unilamellar Hybrid Vesicles

Abstract

Abstract Hybrid vesicles of lipid and amphiphilic block copolymer combine the biological and functional versatility of lipid delivery systems with the mechanical stability and robustness of polymersomes. While studies of hybrid systems for ease of characterization have focused on giant vesicles, most encapsulation and release applications require nanoscale (large) unilamellar vesicles. We investigate the structure and physical characteristics important for thermal actuation of vesicle‐forming blends of saturated phospholipid, polybutadiene‐ b ‐poly(ethylene oxide) and thermoresponsive polyisoprene‐ b ‐poly( N ‐isopropylacryl amide) that are additionally loaded with hydrophobic superparamagnetic nanoparticles in the vesicle membrane and resized to large unilamellar vesicles. Lipid/diblock copolymer hybrid vesicles are shown to be the most efficient option to trigger release of encapsulated compounds by application of an external magnetic field causing local hyperthermia. This superiority is shown to depend on the controlled formation of nanoscale lipid domains in the hybrid vesicle membrane and the efficient loading of hydrophobic nanoparticles into the diblock copolymer membrane that retains its stability.