Tuneable Time Delay in the Burst Release from Oxidation‐Sensitive Polymersomes Made by PISA

Abstract

The confinement in and the selective release from vesicular structures is an elementary part of biological transport processes and highly attractive for drug delivery systems. Reactive polymersomes represent a versatile artificial cargo carrier system, which can facilitate an immediate release in response to a specific stimulus. The herein presented oxidation-sensitive polymersomes feature a time delayed release mechanism in an oxidative environment, which can be precisely adjusted by either tuning the membrane thickness or partial pre-oxidation. These polymeric vesicles are conveniently prepared by polymerization-induced self-assembly (PISA) allowing the straightforward and effective in situ encapsulation of cargo molecules, as exemplarily shown for fluorescence dyes and functional enzymes. Detailed kinetic studies revealed a critical degree of oxidation causing the destabilization of the membrane, while no release of the cargo is observed beforehand. The encapsulation of glucose oxidase transforms these polymersomes directly into glucose-sensitive vesicles, as small molecules including sugars can passively penetrate their membrane. Considering the ease of preparation, the presented polymersomes represent a versatile platform for the confinement and a burst release of cargo molecules after a precisely adjustable time span in the presence of specific triggers, such as hydrogen peroxide or glucose.