How preparation and modification parameters affect PB‐PEO polymersome properties in aqueous solution

Abstract

The effect of formation and modification methods on the physical properties of polymersomes is critical for their use in applications relying on their ability to mimic functional properties of biological membranes. In this study, we compared two formation methods for polymersomes made from polybutadiene-polyethylene oxide diblock copolymers: detergent-mediated film rehydration (DFR) and solvent evaporation (SE). DFR-prepared polymersomes showed a three times higher permeability compared to SE-prepared polymersomes as revealed by stopped-flow light scattering. SE-prepared polymersomes broke down faster to structures <50 nm diameter when processed with extrusion, which was more pronounced at 5 mg mL 21 , compared to 10, 20, and 25 mg mL 21 . Our results indicate that the bilayer of SE-prepared polymersomes has a lower apparent fluidity. We also investigated the role of n-octyl-b-D-glucopyranoside (OG), a detergent typically used for reconstitution of membrane proteins into lipid bilayers. Specifically, we compared dialysis and biobeads for OG removal to investigate the influence of these methods on bilayer conformation and polymer rearrangement following detergent removal. There was no significant difference found between method, temperature, or time within each method. Our findings provide insight on how biocompatible polymersome production affects the physical properties of the resulting polymersomes.

Selecting analytical tools for characterization of polymersomes in aqueous solution

“…This is conrmed in other studies. 3,135,136 The zeta potential is a measure of the electrostatic repulsion between particles. Particles with a zeta potential >30 mV or <À30 mV will repel each other and thereby avoid aggregation, where they will aggregate in the intermediate range.…”

Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis

“…Block copolymers are of considerable scientific and technological interest due primarily to their inherent ability to form well-defined nanoscale structures in both melts − and solutions. − Additionally, their chemically dissimilar blocks, and consequently microdomains, provide beneficial property combinations such as mechanical rigidity and ion transport in, for example, poly­[(methyl methacrylate)- b -(1-[(2-methacryloyloxy)­ethyl]-3-butylimidazolium bis­(trifluoromethanesulfonyl)­imide)] diblock copolymers − or amphiphilicity in poly­[butadiene- b -(ethylene oxide)] diblock copolymers. − The formation of nanoscale structures is driven largely by interblock thermodynamic incompatibility, expressed as χ i‑j N , where χ i‑j is the Flory–Huggins interaction parameter between the i and j species, and N denotes the number of statistical repeat units along the copolymer backbone. In melts possessing sufficient incompatibility, the copolymer composition ( f i , the number fraction of i units in the copolymer) primarily dictates interfacial packing and, hence, morphological characteristics.…”