Thermo- and oxidation-responsive supramolecular vesicles constructed from self-assembled pillar[6]arene-ferrocene based amphiphilic supramolecular diblock copolymers

Novel thermo- and oxidation-responsive supramolecular polymeric vesicles in water were constructed from amphiphilic supramolecular diblock copolymers at 37 °C via pillar[6]arene-ferrocene based host–guest interaction, in which the host polymer was pillar[6]arene-terminal-modified poly(N-isopropylacrylamide) (PNIPAM-P[6]) synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization and the guest polymer was ferrocene-terminal-modified methoxy-poly(ethylene glycol) (mPEG-Fc). The host polymer formed micelles in water at 25 °C, and upon addition of guest mPEG-Fc, a hydrophilic supramolecular diblock copolymer PNIPAM-P[6] ⊃ mPEG-Fc was formed, which could become amphiphilic when heated to 37 °C and further self-assembled into supramolecular polymeric vesicles. The resulting vesicles exhibited good thermo- and oxidation-responsiveness, due to the solubility of the host polymer at different temperatures and the oxidation of the ferrocene moiety of the guest polymer, respectively. More importantly, the supramolecular polymeric vesicles could be further applied in the encapsulation of an anticancer drug (doxorubicin hydrochloride) and its controlled release in response to temperature and oxidizing agents.