Synthesis and self-assembly of poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)and their oxidation-sensitive polymersomes

Amphiphilic block copolymers poly(ethylene glycol)-block-poly(N-3-(methylthio)propyl glycine)(PEGb-PMeSPG)were synthesized via ring-opening polymerization of N-3-(methylthio)propyl glycine Nthiocarboxyanhydride(MeSPG-NTA)initiated by amino-terminated PEG.The self-assemblies of three PEG-b-PMeSPG copolymers with different PMeSPG block lengths were first prepared by nanoprecipitation method using THF and DMF,respectively,as the organic solvent,and their morphologies were studied by Cryo-EM and DLS.To prepare polymersomes loaded with glucose oxidase(GOx),double emulsion method followed by extrusion treatment was employed.The oxidation-responsive disruption of polymersomes was achieved upon the introduction of glucose because of the oxidants generated insitu by GOx/glucose.

Helical supramolecular nanorods via sequential meticulous tailoring of noncovalent interaction and light irradiation

Polymers are widely recognized to entail random conformations in good solvent governed by the need for achieving the highest entropy to reach thermodynamic equilibrium.In this context,it remains grand challenging to directly arrange them into ordered conformation as building blocks for further self-assembling into hierarchal structures.Herein,we report a simple yet viable strategy to progressively assemble rationally designed azobenzene-containing alternating copolymer(i.e.,poly(binaphthylspacer-azobenzene-alt-hexaethylene glycol),denoting P(BNPSAzo-alt-EG_(6))_(24))into helical supramolecular nanorods.Specifically,P(BNPSAzo-alt-EG_(6))_(24) chains in good solvent are firstly self-assembled into helical single molecular micelles in good solvent via intramolecular π-π interaction between binaphthyl groups as well as between azobenzene moieties.Subsequently,by simply introducing water into the solution that is allowed to dwell for a certain period of time,single molecular micelles are selfassembled into well-defined vesicles.Finally,these isotropic vesicles could be further transformed into anisotropic helical supramolecular nanorods with enhanced aggregate-induced emission(AIE)capability driven by repeated,light-triggered cistrans isomerization of azobenzene moieties with the retention of π-π interacted binaphthyl groups.This study highlights a facile route to yielding morphology-rich,functional assemblies from a single polymer via judiciously exploiting non-covalent interaction and light of different wavelength as highly effective trigger in a non-invasive manner for potential applications in controlled release and fluorescent labelling.