Engineering of ion permeable planar membranes and polymersomes based on β-cyclodextrin-cored star copolymers

For polymersome-based nanoreactor purposes, we herein present the synthesis and characterization of well-defined star amphiphilic copolymers composed of a beta-cyclodextrin (βCD) core and seven poly(butylene oxide)-block-polyglycidol (PBO-PGL) arms per side (βCD-(PBO-PGL)₁₄). The self-assembly behavior of 14-armed βCD-(PBO-PGL)₁₄ and PGL-PBO-PGL (linear analogues without the βCD segment) was investigated using scattering techniques for comparison. The morphologies, including vesicles and micelles, are governed by the hydrophobic-to-hydrophilic (weight) ratio, regardless of the polymer architecture (linear or star). Interestingly, despite notable differences in polymer conformation, the produced supramolecular structures were evidenced to be fairly similar on the structural point of view. We subsequently investigated the ion permeability of the membranes of the self-assemblies focusing on the impact of the presence of βCD. The results demonstrated that the βCD-containing vesicular membranes are less permeable to H⁺, compared with βCD-free vesicular membranes. The presence of βCD in planar membranes also influences the K⁺Cl^- permeability to some extent. Thus, βCD-containing membranes can be considered as potential candidates in designing nano-containers towards applications where precise changes in environmental pH are required.