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Polymersomes with Rapid K+-Triggered Drug-Release Behaviors

You, Xiang-Ru, Ju, Xiao-Jie, He, Fan, Wang, Yuan, Liu, Zhuang, Wang, Wei, Xie, Rui, Chu, Liang-Yin
ACS Applied Materials & Interfaces 2017 v.9 no.22 pp. 19258-19268
composite polymers, doxorubicin, fluorescein, hydrophilicity, hydrophobicity, intracellular fluids, models, neoplasms, phase transition, polyethylene glycol, potassium, therapeutics
A novel type of smart polymersomes with rapid K⁺-triggered drug-release properties is developed in this work. Block copolymers with biocompatible poly(ethylene glycol) (PEG) as the hydrophilic block and poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (PNB) copolymer as the K⁺-responsive block are successfully synthesized. Because of the presence of 18-crown-6 units, the PEG-b-PNB block copolymers exhibit excellent K⁺-dependent phase-transition behaviors, which show a hydrophilic–hydrophobic state in simulated extracellular fluid and present a hydrophilic–hydrophilic state in simulated intracellular fluid. Polymersomes with regular spherical shape and good monodispersity are prepared by the self-assembly of the PEG-b-PNB block copolymers. Both hydrophilic fluorescein isothiocyanate–dextran and hydrophobic doxorubicin are selected as model drugs and are successfully encapsulated into the PEG-b-PNB polymersomes. After being placed in a simulated intracellular fluid with high K⁺ concentration, the PEG-b-PNB polymersomes immediately disassemble accompanied by the rapid and complete release of drugs. Such K⁺-responsive polymersomes with the desired drug-release properties provide a novel strategy for advanced intracellular drug delivery and release, which can enhance the safety and efficacy of cancer therapy.