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

Abstract

Reactive polymersomes represent av ersatile artificial cargo carrier system that can facilitate an immediate release in response to aspecific stimulus.The herein presented oxidation-sensitive polymersomes feature at ime-delayed release mechanism in an oxidative environment, whichc an be precisely adjusted by either tuning the membrane thickness or partial pre-oxidation. These polymeric vesicles are conveniently prepared by PISA allowing the straightforwarda nd effective in situ encapsulation of cargo molecules,asshown for dyes and enzymes.Kinetic studies revealed acritical degree of oxidation causing the destabilization of the membrane,w hile no release of the cargo is observed beforehand. The encapsulation of glucose oxidase directly transforms these polymersomes into glucose-sensitive vesicles,a ss mall molecules including sugars can passively penetrate their membrane. Considering the ease of preparation, these polymersomes represent av ersatile platform for the confinement and burst release of cargo molecules after ap recisely adjustable time span in the presence of specific triggers,s uch as H 2 O 2 or glucose.

RAFT-mediated polymerization-induced self-assembly (RAFT-PISA): current status and future directions

“…The encapsulated GOx not only retained its activity but also transformed the hybrid vesicle into glucose-responsive nanoreactors that can undergo self-degradation by converting glucose to H 2 O 2 . 247 …”

“…With the addition of glucose, H 2 O 2 was generated by GOx catalysis, leading to the full disassembly of vesicles. 247 …”

“…The CO 2 -responsive nature of the PDMAEMA block allowed the triggered release of silica nanoparticles under mild conditions. 244 Recently, more cargo species have been encapsulated into PISA-prepared vesicles, including enzymes, dyes and drugs, 35,36,[245][246][247] and the activity of the encapsulated species were investigated. For example, Gibson and O'Reilly et al reported the permeability of PHPMA vesicle membranes by showing the encapsulated enzyme remained active while inside the vesicles.…”

“…Similarly, thioether-containing monomer N-acryloylthiomorpholine (NAT) was used to prepare oxidation-responsive nanoparticles via PISA. 246,247 Brendel et al synthesized poly(Nacryloylmorpholine) (PNAM)-based macro-CTA for the dispersion polymerization of NAT, and the obtained biocompatible spherical micelles exhibited different diameters. Upon exposure to H 2 O 2 , the oxidation of thioether moiety led to a gradual increase in the hydrophilicity of the core and the ultimate disassembly.…”

ROS‐Sensitive Polymer Micelles for Selective Degradation in Primary Human Monocytes from Patients with Active IBD

“…The presence of thioether groups after disintegration have also been confirmed in a subsequent study on the polymer oxidation. [ 40 ] A further delay is now observed when the micelles were incubated in 10% FBS medium with 1 mol H 2 O 2 , as the fluorescence intensity was only reduced by around 65% after 2 h (Figure S2B, Supporting Information). It is interesting to note that no change is observed, if the loaded micelles are kept in the medium without H 2 O 2 .…”