Polymersomes: Tough Vesicles Made from Diblock Copolymers

TLDR

Polymer EO40‑EE37 has a molecular weight several times higher than typical phospholipids in natural membranes. Amphiphilic diblock copolymers were used to form vesicles, which were then characterized by micromanipulation. Polymersomes exhibit bending and area‑expansion moduli comparable to lipid membranes yet are nearly an order of magnitude tougher, withstand greater areal strain before rupture, and are at least ten times less permeable to water, indicating a new class of synthetic thin‑shelled capsules.

Abstract

Vesicles were made from amphiphilic diblock copolymers and characterized by micromanipulation. The average molecular weight of the specific polymer studied, polyethyleneoxide-polyethylethylene (EO 40 -EE 37 ), is several times greater than that of typical phospholipids in natural membranes. Both the membrane bending and area expansion moduli of electroformed polymersomes (polymer-based liposomes) fell within the range of lipid membrane measurements, but the giant polymersomes proved to be almost an order of magnitude tougher and sustained far greater areal strain before rupture. The polymersome membrane was also at least 10 times less permeable to water than common phospholipid bilayers. The results suggest a new class of synthetic thin-shelled capsules based on block copolymer chemistry.