Cosurfactant-Induced Disorder in Polymersome Membrane Enhances Diffusion of Cargo Molecules

Giant polymersomes are widely used as artificial cells due to their resemblance to natural cells; however, their intrinsically low membrane permeability remains a major limitation for applications such as drug delivery and bioreactors. Here, we report a microfluidic approach to fabricate permeable polymersomes using PB-b-PEO as a macromolecular surfactant and oleyl alcohol as a cosurfactant. Incorporation of the cosurfactant into the membrane induces membrane structural disorder in polymer packing, leading to enhanced membrane permeability. Using advanced nuclear magnetic resonance (NMR) spectroscopy, we directly probe the heterogeneity within polymersome membranes, representing membrane-level investigation in giant polymersomes. Comparison with polymersomes exhibiting tightly packed polymer assemblies reveals pronounced differences in the lateral mobility and permeability of the membrane. Our results demonstrate how subtle changes in formulation translate into distinct membrane structures, establishing a molecular basis for the rational design of polymersomes with tailored permeability.